Download - Biology Experiment Book Cover - PDST biology book for publication.pdf · • Manipulation of apparatus • Followinginstructions • Observation • Recording • Interpretationof

Contents Record of Experimental Work Unit 1 ...................................................................................................... 4

Record of Experimental Work Unit 2 ...................................................................................................... 5

Record of Experimental Work Unit 3 ...................................................................................................... 6

Skills and Hints ........................................................................................................................................ 7

Conduct a qualitative test for starch ...................................................................................................... 8

Conduct a qualitative test for a reducing sugar .................................................................................... 12

Conduct a qualitative test for protein .................................................................................................. 16

Conduct a qualitative test for fat .......................................................................................................... 20

Identify any five fauna and any five flora using simple keys. ............................................................... 25

Identify and use various apparatus required for collection methods in an ecological study. .............. 31

Conduct a quantitative study of plants and animals of a sample area of the selected ecosystem...... 36

Investigate any three abiotic factors present in the selected ecosystem, as listed in syallabus …......45

Be familiar with and use the light microscope ..................................................................................... 51

Prepare and examine one animal cell, unstained and stained, using the light microscope ................ 56

Prepare and examine one plant cell, unstained and stained, using the light microscope .................. 60

Investigate the effect of pH on the rate of enzyme activity ................................................................. 68

Investigate the effect of temperature on the rate of enzyme activity ………………………………………….… 74

Investigate the effect of heat denaturation on the activity of an enzyme ........................................... 80

Prepare an enzyme immobilisation and examine its application ......................................................... 85

Conduct any activity to demonstrate osmosis ..................................................................................... 89

Investigate the influence of light intensity on the rate of photosynthesis ........................................... 94

Prepare and show the production of alcohol by yeast ....................................................................... 101

Isolate DNA from a plant tissue .......................................................................................................... 107

Investigate the growth of leaf yeast using agar plates and controls .................................................. 113

Prepare and examine microscopically the transverse section of a dicotyledonous stem ................. 119

Dissect, Display and Identify a sheep’s heart ..................................................................................... 123

Investigate the effect of exercise on the human pulse rate ............................................................... 128

Investigate the effect of exercise on the breathing rate .................................................................... 133

Investigate the effect of IAA growth regulator on plant tissue .......................................................... 138

Investigate the effects of water, oxygen and temperature on germination ...................................... 147

Use starch agar or skimmed milk plates to show digestive activity during germination................... 152 Visuals for Experiments....................................................................................................................... 156

2

Record of Experimental Work Unit 1

Experiment Title Unit 1

Date Experiment Completed

Date Write up Completed

Questions Completed

Y/N

Testing Food for Starch

Testing Food for Reducing Sugar

Testing Food for Protein

Testing Food for Fat

Identifying Flora and Fauna using

keys.

Identify a variety of Habitats

Identify and use various apparatus

required for collection methods in an

Ecological study.

Quantitative Survey: Plants

Method: _____________________

Quantitative Study: Animals

Method: _____________________

Investigating Abiotic Factors

Factors: 1.

2.

3.

4



Date Experiment

Completed

Date Write up

Completed

Questions

Completed

Y/N

Using the Microscope

Looking at Animal (cheek) Cells

Looking at Plant Cells

pH and Enzyme Activity

Temp and Enzyme Activity

Enzyme Denaturation

Enzyme Immobilsation

Osmosis

Photosynthesis

Fermentation of Alcohol

Isolating DNA

5



Date Experiment

Completed

Date Write up

Completed

Questions

Completed

Y/N

Leaf Yeast Growth

Heart Dissection

Exercise and the Pulse Rate

Exercise and the Breathing Rate

TS of a Dicot Stem

IAA as a Growth Regulator

Germination

Digestive Activity during

Germination

6

Skills and Hints

The skills developed primarily through the practical activities include:

• Manipulation of apparatus

• Following instructions

• Observation

• Recording

• Interpretation of observations and results

• Practical enquiry and application of results

Manipulation of apparatus involves manual dexterity and efficiency for example:

• using appropriate methods in collecting required specimens in an ecological study

• being familiar with and using the light microscope

• dissecting a sheep's heart

• conducting a series of laboratory activities and investigations safely and humanely

Following instructions involves adherence to the instructed or recorded sequence of actions required to carry out an activity e.g. the ability to follow instructions from a practical manual.

Observation is the most important aspect of the scientific method. All knowledge of biology is based on situations in which a biologist observes a particular event and records it. Instruments are used to extend our perceptual limits. Appropriateness, accuracy and completeness of observation need to be practiced, monitored and guided from relevant theoretical criteria.

Recording is another essential aspect of the scientific method. Records are proof of what has been completed in the activity and what can be repeated with similar expected outcomes.

Interpretation of observations and results should ensue from the hypothesis being tested or the investigation undertaken. The final interpretation should be coherent and should explain clearly how your conclusions are reached.

Practical inquiry and application of results e.g. if results are ambiguous, you should consider your results, and where necessary repeat the activity or design a new activity. You should consider the results in a wider context and make suggestions or identify the activity as a scientific paradigm (an activity that serves as a model for further work).

7

Conduct a Qualitative Test for Starch

Date the experiment was completed: _________________ Materials/Equipment/Apparatus:

Procedure/Method:

List steps taken with reasons:

8

Safety/Risks:

Labelled diagram:

Results:

Sample Initial Colour Final Colour Starch Solution Water

Conclusion:

9

Questions on Qualitative Test for Starch: 1. State clearly the aim of this experiment.

__________________________________________________________________________________

__________________________________________________________________________________

2. Name the three chemical elements present in starch.

__________________________________________________________________________________

3. To what food group does starch belong?

__________________________________________________________________________________

4. Name three foods that contain starch.

(i)

_______________________________________________________________________

(ii)

_______________________________________________________________________

(i) _____________________________________________________________________

5. What is the function of starch in the diet?

__________________________________________________________________________________

6. Draw a labeled diagram of the apparatus you will use in this experiment.

7. What chemical is used to test for starch?

__________________________________________________________________________________

8. When this chemical is added to starch, what colour change will be observed?

__________________________________________________________________________________

9. Is heat needed?

__________________________________________________________________________________

10

10. Suggest a control for this experiment.

__________________________________________________________________________________

11. Why do you swirl the solutions in the test tubes?

__________________________________________________________________________________

12. What colour change indicates a positive result?

__________________________________________________________________________________

13. Name an enzyme in the body that breaks down starch.

__________________________________________________________________________________

14. State where in the digestive system this enzyme acts.

__________________________________________________________________________________

15. What is the product of this enzyme’s action?

__________________________________________________________________________________

16. When starch is fully digested, what sub-unit is formed?

__________________________________________________________________________________

17. Name the structure in the gut through which this sub-unit is absorbed.

__________________________________________________________________________________

18. Name the blood vessel that connects the small intestine to the liver.

__________________________________________________________________________________

11

Conduct a Qualitative Test for a Reducing Sugar


Procedure/Method:


12

Safety/Risks:

Labelled diagram:

Results:

Sample Initial Colour Final Colour Glucose Solution Water

Conclusion:

13

Questions on Qualitative Test for a Reducing Sugar:

1. Give one example of

a monosaccharide ____________________________________________________________

a disaccharide _______________________________________________________________

a polysaccharide _____________________________________________________________

2. Give one example of a reducing sugar and state its function in the body

Name: ________________________________________________________________________

Function: ______________________________________________________________________

3. What reducing sugars did you use in this experiment?

__________________________________________________________________________________

4. What did you use as a control?

__________________________________________________________________________________

5. What reagent did you use?

__________________________________________________________________________________

6. Did you need to use heat and if so, how did you heat the solution?

__________________________________________________________________________________

7. When Benedict’s reagent is added to a reducing sugar and heated, what colour change occurs?

__________________________________________________________________________________


__________________________________________________________________________________

9. Was there a colour change in the control?

__________________________________________________________________________________

14

10. If you used a mortar and pestle in this experiment what was its function?

__________________________________________________________________________________

__________________________________________________________________________________

11. If sucrose was used with the reagent, what result would you expect? Explain your answer.

__________________________________________________________________________________

__________________________________________________________________________________

12. By what process are reducing sugars made in plants?

__________________________________________________________________________________

13. State a use for the benedicts test in the biology laboratory

__________________________________________________________________________________

How to remember this experiment!

“Pope Benedict with his sweet tooth takes a hot bath in his brick red house”

15

Conduct a Qualitative Test for Protein


Procedure/Method:


16

Safety/Risks:

Labelled diagram:

Results:

Sample Initial Colour Final Colour Protein Solution Water

Conclusion:

17

Questions on Qualitative Test for Protein: 1. Name the chemical elements present in a protein.

__________________________________________________________________________________

2. Name 3 foods that contain protein.

__________________________________________________________________________________

__________________________________________________________________________________

3. What are the products of the digestion of protein?

__________________________________________________________________________________

4. Give one example of a structural protein and one example of a metabolic protein.

__________________________________________________________________________________

__________________________________________________________________________________

5. State one reason that your body needs protein.

__________________________________________________________________________________

6. What chemical(s) is used to test for protein?

__________________________________________________________________________________

7. When this chemical(s) is added to protein, what colour change is observed?

__________________________________________________________________________________

8. Suggest a control for this experiment?

__________________________________________________________________________________

9. State 2 precautions you should consider before carrying out this experiment.

__________________________________________________________________________________

__________________________________________________________________________________

18

10. What 2 chemicals make up the biuret reagent?

_________________________________________________________________________________

11. Was heat needed for this test?

_________________________________________________________________________________

12. Name an enzyme that acts on protein in the body and the product formed.

_________________________________________________________________________________

13. Of what sub-unit are proteins made?

_________________________________________________________________________________

14. Name the infolding in the small intestine through which these sub-units are absorbed.

_________________________________________________________________________________

15. Name the blood vessel by which these sub-units are transported to the liver.

_________________________________________________________________________________

16. Excess of these sub-units are converted to _____________________by a process called

_________________________ in the liver.

17. To which group of molecules do enzymes belong? _________________________________________

18. State one reason that your body need protein

___________________________________________________________________________________

19. Name the element, other than carbon, hydrogen and oxygen, which is always found in protein

__________________________________________________________________________________

20. Name two foods in which you found protein.

_________________________________________________________________________________

19

Conduct a Qualitative Test for Fat


Procedure/Method:


20

Safety/Risks:

Labelled diagram:

Results:

Sample Translucent Spot Before Drying After Drying Oil Water

Conclusion:

21

Questions on Qualitative Test for Fat: 1. Name the 3 chemical elements present in fat.

__________________________________________________________________________________

2. Name 3 foods that contain fat.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

3. What are the products of the digestion of fats?

__________________________________________________________________________________

4. Where is fat stored in animals?

__________________________________________________________________________________

5. What will you use to test for the presence of fat?

__________________________________________________________________________________

6. What result will indicate the presence of fat?

__________________________________________________________________________________

7. Suggest a control in this experiment.

__________________________________________________________________________________

14. Name and give an example of the two states of fat at room temperature.

__________________________________________________________________________________

15. Name an enzyme that acts on fat.

_________________________________________________________________________________

16. What are fats broken down to in the body?

__________________________________________________________________________________

22

17. Into what structure are the digested end products absorbed?

__________________________________________________________________________________

18. This structure is part of what system?

__________________________________________________________________________________

19. Through what blood vessel does fat re-enter the blood stream?

__________________________________________________________________________________

20. State a role of fat in the body.

__________________________________________________________________________________

21. In what way do fats differ from carbohydrates in terms of their elements?

__________________________________________________________________________________

22. In what structure are phospholipids located?

__________________________________________________________________________________

23. State the difference between a lipid and a phospholipid

__________________________________________________________________________________

23

Skills for Food Tests

Skill Achieved 1. Following Instructions Familiarise yourself with all procedures

before starting Follow your step by step method Listen to your teacher’s instructions

2. Manipulation of apparatus

Fill and empty the pipette Set up the water bath Use the test-tube holder safely Use the timer accurately Label the tubes correctly Swirl the tubes

3. Observation Observe a colour change Note the appearance of the translucent spot Appreciate the significance of heat in the Test for Sugar Notice the effect of swirling

4. Recording Write up the procedure Record colour change/translucent spot Tabulate results Compare with controls

5. Interpretation Draw reasonable conclusions about foods tested from your observations and results

6. Application Become aware of any other application(s) of what you learned in this activity

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label the test tubes as appropriate Work in an organised and efficient manner Clean up after the practical activity

Hints for Food Tests

• To quickly dry the brown paper in the fat test place it on a radiator for a minute or two.

• Filter paper may be used instead of brown paper in the fat test.

• When carrying tubes a test-tube holder tends to be better than a tongs.

• When using Benedict’s reagent it is essential to use the qualitative rather than quantitative type to obtain a brick-red colour with a reducing sugar

24

Ecology: Identify any five fauna and any five flora using simple

keys. Identify a variety of habitats within the selected ecosystem


Procedure/Method:

(a) To identify fauna and flora


(b) To identify a variety of habitats in the ecosystem


25

Safety/Risks:

Results table:

Organism identified: Identifying feature(s): Habitat:

Organism identified: Identifying feature(s): Habitat :Organism identified





26







Conclusion:

27

Skills for Identifying Flora and Fauna


before starting Follow your step by step method Listen to the teacher’s instructions


Use identification keys to identify flora Use identification keys to identify fauna Use a hand lens correctly Handle the organisms with care

3. Observation Observe a variety of habitats Note the features of both flora and fauna Notice adaptations of organisms Observe the effect of using a hand lens

4. Recording Write up the procedure Draw a map/sketch of the ecosystem Tabulate results

5. Interpretation Draw reasonable conclusions about the flora and fauna present in the habitat(s) observed from your observations and results

6. Application Become aware of any other application(s) of what you learned in this activity for examples the use of key in a diagnosing tree to diagnose disease

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Work in an organised and efficient manner Leave the area as you found it

Hints for Identifying Flora and Fauna using a key:

• Although it is not on the syllabus, it is sometimes useful to have students make a dichotomous key using objects they already know, e.g. lab equipment or photos of known animals. This helps them to understand how a key works.

• Collect fauna using appropriate apparatus to help the identification process, e.g. a net. • When using a dichotomous key, always read both descriptions in the couplet even if the first

one seems to be the logical one. If a choice is not clear, follow both options. If two answers are still possible, follow both alternative paths until an answer becomes clear.

• Avoid guessing the measurements of the specimen. Use a calibrated scale. A section of a metre stick may be photocopied onto an acetate sheet and held on a clipboard for easy access during your fieldwork

• Hold small animals in a clear plastic con tainer, not glass.

• Use a good quality hand lens, one with a 10x magnification

28

Questions on Identifying Flora and Fauna:

1. Use the following key to identify each of these animals. Write down each letter and the animal it represents in your answer book.

1. Jointed legs present ………………………………………….… 2 Jointed legs absent ……………………………………………..….… 3 2. Three pairs of jointed legs….……………………….………....... Diving beetle

Four pairs of jointed legs……………………..………………...… Water mite 3. Body divided into segments……………………….………....... Leech

Body not divided into segments……………………….....…… 4 4. Shell present ….……………………………………………........……. Pond snail

Shell absent ............................................................…... 5 5. Ring of tentacles around the mouth……….………………… Hydra

No tentacles……………………………………………………..….…… 6 6. Flat body with eye spots………………………………………..…. Planarian

Round body with pointed ends ………………………..……… Nematode

2. In ecological studies what is a key?

__________________________________________________________________________________

__________________________________________________________________________________

3. How is a key used?

__________________________________________________________________________________

__________________________________________________________________________________

29

4. What are the main characteristics that you used to identify plants in the habitat studied?

__________________________________________________________________________________

__________________________________________________________________________________

5. Name one animal that you identified in your ecosystem.

__________________________________________________________________________________

6. State two features that this animal had to allow you to identify it

__________________________________________________________________________________

__________________________________________________________________________________

7. How were you able to identify animals that you found in an ecosystem?

__________________________________________________________________________________

8. What is meant by the term fauna? ____________________________________________

9. What is meant by the term flora? _____________________________________________

30

Ecology: Identify and use various apparatus required for collection

methods in an ecological study.


Procedure:

1. In the tables below name the equipment that you are going to use to collect fauna from the habitats in the ecosystem you are studying

2. Draw a sketch of the equipment 3. Describe how the equipment is used to collect the organism 4. Name the type of organism collected using the equipment

Name of equipment Diagram

How used • • •

Organism(s) collected




31










Safety/Risks:

32

Results:

Name of organism (5 plants and 5 animals)

Habitat (where found) in the ecosystem

A structural adaptation you observed

Collection apparatus used

Conclusion:

33

Skills for Collection Apparatus:

Skill Achieved

1. Following Instructions Familiarise yourself with all procedures before starting Follow your step by step method Listen to the teacher’s instructions


Identify collection apparatus appropriate to the ecosystem you are studying Use each piece of apparatus appropriately

3. Observation Note the use of each piece of apparatus Identify each piece of apparatus used Identify the organisms collected

4. Recording Write up the procedure Draw diagrams of apparatus Tabulate results

5. Interpretation Draw reasonable conclusions about the range of organisms in your habitat and the suitability of equipment for collection of organisms from your observations and results


7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label as appropriate Carefully return any collected fauna to where they were found Leave the area as you found it

Hints for Collection Apparatus:

• Mark the mouthpiece on your pooter with coloured tape to avoid sucking the wrong tube • When setting pitfall traps, make sure there are no gaps between the rim of the trap and

the edge of the hole. • After collecting pitfall traps, fill in the holes with soil. • When using a beating tray, it is important not to disturb the vegetation to be

investigated until you are ready to apply the vigorous shake. • If a pitfall trap is being used for capture-recapture, bait could be used. • When using a plankton net, it is necessary to draw it through the water for a distance of

approximately 250m. • When setting small mammal traps, ensure they are stable and the chamber is sloped to

prevent water running in. • Bedding and bait should be placed in small mammal traps.

34

Questions on Collection Apparatus: 1. List 5 pieces of equipment you used to study an ecosystem

__________________________________________________________________________________

__________________________________________________________________________________

2. What is ecology?

__________________________________________________________________________________

3. What is meant by environment?

__________________________________________________________________________________

4. What is an ecosystem?

__________________________________________________________________________________

5. Can you name some ecosystems?

__________________________________________________________________________________

6. What is the biosphere?

__________________________________________________________________________________

7. What is a habitat?

_________________________________________________________________________________

8. What is a community?

__________________________________________________________________________________

9. All organisms are adapted to live successfully in their ecosystem/habitat. Adaptations can be

(a) Structural, (b) Competitive or (c) Behavioural. Distinguish between these 3 categories of

adaptations by explaining each one and name one organism and its adaptation for each category.

(a) Structural Adaptation

__________________________________________________________________________________

_________________________________________________ ________________________________

Organism name _______________________________ Adaptation _____________________

(b) Competitive Adaptation

__________________________________________________________________________________

_________________________________________________ ________________________________

Organism name _______________________________ Adaptation ____________________

(c) Behavioural Adaptation

__________________________________________________________________________________

__________________________________________________________________________________

Organism name _______________________________ Adaptation ____________________

35

Ecology: Conduct a quantitative study of plants and animals of a

sample area of the selected ecosystem (a)

Transfer results to tables, diagrams, graphs, histograms, or any other relevant mode. Identify possible sources of error in such a study.

The syllabus requires that students carry out 1 quantitative method for 2 plants and 1

quantitative method for 2 animals

Method 1: FREQUENCY or % FREQUENCY – suitable for plants or sessile animals (e.g. limpets) Date the experiment was completed: _________________ Materials/Equipment/Apparatus:

Procedure/Method for PLANTS and sessile ANIMALS (e.g. limpet)

Frequency or % Frequency


Labelled diagram:

36

Results: when using a frame quadrat

If percentage frequency is required use formula:

% Frequency = Frequency x 100 Transfer your result to labelled bar chart:

Possible sources of error.

Safety/Risks:

thrownquadratsofNoorganismcontainingquadratsofNo

Frequency.

.=

Organism 1 2 3 4 5 6 7 8 9 10 Total Frequency % FrequencyQuadrat throw

37

Ecology: Conduct a quantitative study of plants and animals of a sample area of the selected ecosystem (b)

Transfer results to tables, diagrams, graphs, histograms, or any other relevant mode. Identify possible sources of error in such a study.

The syllabus requires that students carry out one quantitative method for 2 plants and one

quantitative method for 2 animals

Method 2: % Cover – suitable for ‘cover’ plants (e.g. grass) or abundant sessile animals (e.g. barnacles) Date the experiment was completed: _________________ Materials/Equipment/Apparatus:

Procedure/Method for PLANTS and sessile ANIMALS (e.g. barnacle)

% Cover


Labelled diagram:

38

Results: when using a 25-point gridded quadrat Transfer results to tables, diagrams, graphs, histograms, or any other relevant mode. A pie chart is a good way to display these results Possible sources of error.

Safety/Risks:

Organism Name 1 2 3 4 5 6 7 8 9 10

Total no. of Hits Total Points % Cover

e.g. Grass 250250

Quadrat throw

100int.Τ

.% ×=spoofnootal

hitsofNoCover

39

Ecology: Conduct a quantitative study of plants and animals of a sample area of the selected ecosystem (c)

Transfer results to tables, diagrams, graphs, histograms, or any other relevant mode. Identify possible sources of error in such a study. The syllabus requires that students carry out any one quantitative method for 2 plants and any

one quantitative method for 2 animals.

Method 3: Capture/recapture method. Suitable for some animals e.g. snails Date the experiment was completed: _________________ Materials/Equipment/Apparatus:

Procedure/Method for animals

Capture/recapture


40

Labelled diagram: Results for Capture/Recapture method:

Name of animal

Method of capture Method of marking Number captured and marked – first time Number of animals captured – second time Number of the recaptures i.e. those that were marked when caught at the second time

Population = Number caught 1st time x number caught 2nd time

Number that were recaptured (i.e. marked) Population range can be measure by repeating the activity a few more times. The population range is between the lowest and the highest number calculated Possible sources of error.

Safety/Risks:

41

Skills for Quantitative Studies:




Identify apparatus appropriate to the ecosystem you are studying Use each piece of apparatus appropriately for estimating numbers of flora and fauna

3. Observation Observe the distribution of organisms in an ecosystem Observe a variety of habitats within an ecosystem Note the use of each piece of apparatus Identify each piece of apparatus used Identify the different species present at various times

4. Recording Write up the procedure Draw a diagram if necessary Tabulate results

5. Interpretation Draw reasonable conclusions from your observations and results


7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label apparatus as appropriate Ensure not to mark any fauna so that they will become more obvious to prey Leave the area as you found it

Hints for Quantitative Studies:

• Mark off the sample area by using poles with string or flags or by other visible markers e.g. trees,

paths, rocks, etc.

• Throw a small object over your shoulder to select a random sample point.

• Place the quadrat down carefully so that the animals are not disturbed allowing you to count

them.

• Pour water onto the ground in the quadrat to get the slugs and earthworms to come to the surface

where they can be seen and counted.

• In the capture-recapture technique, use poster paints to mark animals, as this paint will wear off

after a short time. This will reduce their chance of being preyed upon.

42

Questions on Quantitative Studies in Ecology:

1. Distinguish between a qualitative and quantitative ecological survey. __________________________________________________________________________________

__________________________________________________________________________________

2. What is meant by percentage cover in an ecological survey of an ecosystem?

__________________________________________________________________________________

__________________________________________________________________________________

3. In the case of a named plant describe how you estimated the percentage cover of this plant in

the ecosystem that you studied.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

4. Describe how you recorded your results of the above experiment

_________________________________________________________________________________

_________________________________________________________________________________

5. Suggest a possible source of error in your study

_________________________________________________________________________________

_________________________________________________________________________________

6. What is a quadrat?

__________________________________________________________________________________

7. Why were the quadrat sites chosen randomly?

__________________________________________________________________________________

__________________________________________________________________________________

8. How did you ensure that the quadrat sites were chosen randomly?

__________________________________________________________________________________

__________________________________________________________________________________

43

9. Why would you use ten quadrat throws instead of one?

__________________________________________________________________________________

__________________________________________________________________________________

10. What is the frequency of clover if it is present in 45 out of 50 randomly thrown quadrats?

__________________________________________________________________________________

__________________________________________________________________________________

11. When carrying out a quantitative study why might you use a line transect instead of a quadrat?

__________________________________________________________________________________

__________________________________________________________________________________

12. Why is the quadrat method not always suitable for estimating the numbers of animals in a

habitat?

__________________________________________________________________________________

__________________________________________________________________________________

44

Investigate any three abiotic factors present in the selected

ecosystem, as listed in syllabus.

Relate results to choice of habitat selected by each organism identified in your ecological study.


Procedure/Method:

Abiotic Factor 1 – Name:




45



Safety/Risks:

Labelled diagrams of apparatus:

Name: Name: Name:

46

Results chart – complete for at least 3 factors appropriate to your selected ecosystem Factor Apparatus or method used Result (include units)

Soil temperature range Air temperature range Water temperature range Soil pH Average wind speed Light Intensity % air in soil

% water in soil

Results related to choice of habitat selected by identified organisms

Conclusion:

Organism Name Habitat Abiotic Factor affecting suitability for organism

Daisy Open grassland area Daisy favours high light intensity habitat

47

Skills for Abiotic Factors:




Use each piece of apparatus appropriately

3. Observation Observe the distribution of organisms in an ecosystem Observe a variety of habitats within an ecosystem Note the link between the abiotic factors and the organism’s choice of habitat

4. Recording Write up the procedure Draw a diagram if necessary Tabulate the result



7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label diagrams as appropriate Work in an organised and efficient manner Leave the area as you found it

Hints:

• If you have data logging equipment use it to measure salinity, dissolved oxygen, pH and temperature.

• Relate the distribution of the organisms to the abiotic factors

48

Question on Abiotic Factors: 1. What is meant by the term Abiotic factor?

___________________________________________________________________________

___________________________________________________________________________

2. How would you investigate a named abiotic factor other than temperature or pH?

Abiotic Factor _______________________________________________________________

How Investigated

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

3. In relation to the ecosystem you have studied describe how two named organisms are

adapted to the abiotic factors present?

Organism 1 _________________________________________________________________________

How Adapted

__________________________________________________________________________________

Organism 2 ________________________________________________________________________

How Adapted

__________________________________________________________________________________

__________________________________________________________________________________

4. Referring to the abiotic factors in the ecosystem list any three and the scientific units

used to measure the quantity

Abiotic Factor Units

49

5. When measuring some factors it is important to measure them over a period of time and get a range of measurements. Name 2 abiotic factors where a range of measurements should be made (a) ________________________ (b)________________________ Why do you think that this is important? ________________________________________________ _________________________________________________________________________________ 6. When measuring some factors it is important to measure them over a period of time and get an average reading. Name 2 abiotic factors where the range of readings should be taken (a) ____________________________ (b)________________________ Why do you think that this is important? ________________________________________________ __________________________________________________________________________________ 7. How might the wind speed affect an ecosystem and what grows there? _______________ __________________________________________________________________________________ 8. How might the light intensity affect an ecosystem and what grows there?______________ __________________________________________________________________________________

50

Be familiar with and use the light microscope


Procedure/Method:


51

Safety/Risks:

Labelled diagram:

Results: Formula for Magnification: Magnification of the Objective lens x Magnification of the Eyepiece lens

Eyepiece Lens Objective Lens Total Magnification X 1 X 4 X4 X 15 X10 1000

Conclusion:

52

Skills for Using the Microscope




Provide a light source Rotate nosepiece so that the low power objective lens is being used first Place the slide on the stage Use the stage clips to hold the slide Use the coarse adjustment wheel Use the iris diaphragm Use the fine adjustment wheel Use the high power objective lens Refocus using the fine adjustment wheel

3. Observation See a clear image Appreciate the importance of the correct placement of the slide Notice the effect of magnification See the effect of adjusting the iris diaphragm Appreciate the use of the coarse adjustment wheel Appreciate the use of the fine adjustment wheel

4. Recording Write up the procedure Name each piece of the microscope Draw labelled diagrams of your observations


6. Application Become aware of any other application(s) of what you learned in this activity for example using the microscope to view other cell types

7. Organisation Exercise caution for your personal safety and for the safety of others Label as appropriate Work in an organised and efficient manner Clean up after the practical activity

Hints for using the microscope:

• Clean the lenses of the microscope using lens tissue • To locate small objects e.g. single cells, reduce the light intensity by closing the iris

diaphragm and traverse the slide methodically • A common mistake is to have too much light coming through the specimen particularly

when viewing under low power. Opening or closing the iris diaphragm will vary the light intensity.

53

Questions on using the Microscope:

1. Name the parts labeled 1- 9 on the diagram of the light microscope and give the function for

each part :

Name Function

1

2

3

4

5

6

7

8

9

2. What apparatus was needed for this experiment?

__________________________________________________________________________________

__________________________________________________________________________________

3. Name one other type of microscope:

__________________________________________________________________________________

54

4. State one advantage of the microscope you have named:

__________________________________________________________________________________

__________________________________________________________________________________

5. When using the light microscope, which objective lens will you rotate into place first?

_________________________________________________________________________________

6. If you think that more or less light is required to view the slide what part of the microscope

will you adjust?

________________________________________________________________________________

7. How do you change the magnification?

__________________________________________________________________________________

8. How do you calculate the total magnification?

__________________________________________________________________________________

9. State one precautions you should consider before carrying out this experiment: Note:

precautions are steps that will help the experiment work well. They are not safety risks.) One

example is given – give another.

Precaution: Clean the lens with lens tissue before use

a) ______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

55

Prepare and examine one animal cell, unstained and stained, using

the light microscope (X100, X400)


Procedure/Method:


56

Safety/Risks:

Labelled diagram:

Results: Draw a labelled diagram of what you saw under the microscope:

Unstained Cheek Cell Under Low Power Unstained Cheek Cell Under High Power

57

Stained Cheek Cell Under Low Power Stained Cheek Cell Under High Power

Conclusion:

58

Skills for Animal Cells

Skill Achieved 1. Following Instructions

Familiarise yourself with all procedures before starting Follow step by step method Listen to the teacher’s instructions


Use the light microscope effectively Use the inoculating loop to gather cheek cells Transfer the sample to the slide Cover the sample with water Apply the cover slip Apply the stain from the dropper Gently wash excess stain off the sample

3. Observation Locate cells View cells under different magnification Differentiate between cells and debris Appreciate the limitation of the unstained preparation Appreciate the value of the stained preparation

4. Recording Write up the procedure Name each piece of apparatus used Draw a label led diagram


6. Application Become aware of any other application(s) of what you learned in this activity for example using other stains to view cell parts

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label as appropriate Work in an organised and efficient manner Clean up after the practical activity

Hints:

• Gloves should be worn when using stains. • Place the slides on a rack over a small tray when staining to avoid spillages on the

desk. • Ethanoic acid (10%) may be used on the unstained animal cell to highlight the

nucleus. Ethanoic acid is not a stain.

59

Questions on Animal Cells: 1. Why did you use methylene blue when examining cheek cells under the microscope?

__________________________________________________________________________________

__________________________________________________________________________________

2. Outline the differences between a plant and animal cell

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

3. State one precaution that you should consider before carrying out this experiment:

(ii) ________________________________________________________________________

________________________________________________________________________

4. What is a tissue?

__________________________________________________________________________________

__________________________________________________________________________________

5. In the space provided, draw a typical animal cell, and label the following parts:

-Cell membrane -Cytoplasm

-Nucleus -Nuclear pores

-Ribosome -Mitochondrion

-DNA

60

6. Describe briefly how you will obtain a sample of human cheek cells

__________________________________________________________________________________

__________________________________________________________________________________

7. Why is a mounted needle used?

__________________________________________________________________________________

8. Outline how you applied the stain to the slide

__________________________________________________________________________________

__________________________________________________________________________________

9. Why is a cover slip placed on the slide?

__________________________________________________________________________________

__________________________________________________________________________________

61

Prepare and examine one plant cell, unstained and stained, using

the light microscope (X100, X400)


Procedure/Method:


62

Safety/Risks:

Labelled diagram:

Results: Draw a labelled diagram of what you saw under the microscope:

Unstained Plant Cell Under Low Power Unstained Plant Cell Under High Power

63

Stained Plant Cell Under Low Power Stained Plant Cell Under High Power

Conclusion:

64

Skills for Plant Cells

Skill Achieved 1. Following

Instructions Familiarise yourself with all procedures before starting Follow step by step method Listen to the teacher’s instructions


Use the light microscope Remove some of the onion epidermis Transfer small pieces of the epidermis to water in the petri dish Put a piece of the epidermis in a drop of water on the slide Apply the cover slip Draw the iodine across under the cover slip, using the filter paper Gently wash excess stain off the sample

3. Observation Locate the epidermis between the fleshy leaves of the onion Locate cells under the microscope View cells under different magnification Appreciate the limitations of the unstained preparation Appreciate the value of a stained preparation

4. Recording Write up the procedure Name each piece of apparatus used Draw a label led diagram


6. Application Become aware of any other application(s) of what you learned in this activity for example using different magnifications and microscope types to identify different organelles and cell processes such as mitosis


Hints:

• Gloves should be worn when using stains. • Place the slides on a rack over a small tray when staining to avoid spillages on the

desk. • Cut small pieces of the onion epidermis while still on the onion. • Multiple nucleoli (two) may be seen in onion nuclei.

65

Questions on Plant Cells: 1. Why are stains often used when examining cells under the microscope?

__________________________________________________________________________________

__________________________________________________________________________________

2. State one precaution you should consider before carrying out this experiment:

(i) ___________________________________________________________________________

______________________________________________________________________________

3. What was the source of the plant cells used in this experiment?

__________________________________________________________________________________

4. State why it is necessary to store the sample in water until you are ready to proceed:

__________________________________________________________________________________

5. Complete the following table:

Name: Function:

Absorbent paper

Iodine

6. Describe briefly how you will obtain a sample of plant cells.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

7. Why do you place a drop of water on the slide before adding the sample on it?

__________________________________________________________________________________

__________________________________________________________________________________

8. Describe how you place the cover slip on the slide.

__________________________________________________________________________________

__________________________________________________________________________________

9. Outline how you use the microscope to examine the cells.

__________________________________________________________________________________

__________________________________________________________________________________

66

__________________________________________________________________________________

__________________________________________________________________________________

10. Which objective lens will you use first to view the cells?

__________________________________________________________________________________

11. What holds the slide in place on the stage?

__________________________________________________________________________________

12. State two features of these cells that indicate that these are plant cells

__________________________________________________________________________________

13. How did you focus the microscope correctly to view the sample?

__________________________________________________________________________________

67

Investigate the effect of pH on the rate of enzyme activity


Procedure/Method:


68

Safety/Risks:

Labelled Diagram

Results:

pH of Buffer Solution Initial Volume (cm3) Final Volume (cm3) Volume of Foam (cm3)

Conclusion:

69

Plot a graph of the rate of Enzyme Activity (i.e. the volume of foam after a stated time) on the Y axis against the pH on the x axis. Label the axes.

70

Skills for pH of Enzymes


before starting Follow step by step method Listen to the teacher’s instructions


Maintain constant temperature (25 °C) in the beaker Obtain enzyme extract Use the syringe correctly Use and read the graduated cylinder correctly Measure pH correctly Use the timer Use the electronic balance

3. Observation Appreciate the use of washing-up liquid Note the evolution of bubbles in the mixture Note the rise of foam in the cylinders Note the colours on the pH papers before and after dipping in solutions if using

4. Recording Write up the procedure Record the volume of foam per unit time Tabulate the results Record the pH in each cylinder Draw a graph with labelled axes


6. Application Become aware of any other application(s) of what you learned in this activity for example in our digestive systems


Hints for pH for enzymes:

• Besides celery there are many other good sources of catalase. Liver is the best source but radish and potato are also good. These can be used chopped. To prepare celery extract, chop 3 stalks and macerate them in a blender in 100 cm3 of distilled water. Filter through coffee filter. If using liver, macerate 5 g in 100 cm3 of distilled water and strain through a household sieve. Use 1 cm3 of these extracts in each cylinder. Increase this volume if activity is low.

• Enzyme preparations lose activity very quickly. Therefore, the enzyme extract must be prepared immediately before use.

• If enzyme activity is high, e.g. when using liver, use larger cylinders.

71

Questions on the effect of pH on enzyme activity: 1. What is an enzyme?

__________________________________________________________________________________

__________________________________________________________________________________

2. Name the enzyme you used and give its source

__________________________________________________________________________________

__________________________________________________________________________________

3. Name the substrate for this enzyme

___________________________________________________________________________________

4. List 3 factors that affect enzyme activity

___________________________________________________________________________________

5. Sketch a graph to show the effect of pH on enzyme activity

6. How would the graph differ for a stomach enzyme?

___________________________________________________________________________________

___________________________________________________________________________________

7. What factors are kept constant during this experiment?

___________________________________________________________________________________

___________________________________________________________________________________

72

8. How is each factor is kept constant?

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

9. How is the rate of enzyme activity measured?

___________________________________________________________________________________

___________________________________________________________________________________

10. How did you know at which pH the enzyme worked best?

___________________________________________________________________________________

___________________________________________________________________________________

11. What is the optimum pH for the enzyme you used?

_________________________________________________________________________________

12. Enzymes are specific. What is meant by specificity of an enzyme?

_________________________________________________________________________________

_________________________________________________________________________________

13. Explain the biological basis for adding enzymes added to some washing powder

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

73

Investigate the effect of temperature on the rate of enzyme activity


Procedure/Method:


74

Safety/Risks:

Labelled diagram:

Results:

Temperature (oC) Initial Volume (cm3) Final Volume (cm3) Volume of Foam (cm3)

Conclusion:

75

Plot a graph of the rate of Enzyme Activity (i.e. the volume of foam after a stated time) on the Y axis against the temperature on the X axis. Label the axes.

76

Skills for Effect of Temperature of Enzymes

Skill Achieved 1. Following Instructions Familiarise yourself with all procedures before

starting Follow step by step method Listen to the teacher’s instructions


Prepare the enzyme source Use the syringe, thermometer, graduated cylinder correctly Use the electronic balance accurately Set up and maintain the water baths Use the test-tube holder Use the timer

3. Observation Appreciate the use of washing-up liquid Note the evolution of bubbles in the mixture Note the rise of foam in the cylinders

4. Recording Write up the procedure Record the temperature each time Record the volume of foam Tabulate the results Draw a graph with labelled axes


6. Application Become aware of any other application(s) of what you learned in this activity for example in baking


Hints for Effect of Temperature of Enzymes • A more accurate value for optimum temperature may be obtained by carrying out

the investigation at more than the minimum five temperatures. • Enzyme preparations lose activity very quickly. Therefore, the enzyme extract must

be prepared immediately before use. • Liver is the best source of catalase but celery, radish and potato are also good. • If activity is high, e.g. when using liver, use larger cylinders.

77

Questions on the effect on temperature on enzyme activity:

1. What is an enzyme? _______________________________________________________________

__________________________________________________________________________________

2. Name the enzyme you used and give its source.

__________________________________________________________________________________

__________________________________________________________________________________

3. Name the substrate for this enzyme.

__________________________________________________________________________________

4. List 3 factors that affect enzyme activity.

__________________________________________________________________________________

__________________________________________________________________________________

5. Sketch a graph to show the effect of temperature on enzyme activity.


__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

78

7. How is each factor kept constant?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________


__________________________________________________________________________________

__________________________________________________________________________________

9. How did you know at which temperature the enzyme worked best ?

__________________________________________________________________________________

__________________________________________________________________________________

10. What is the optimum temperature range for the enzyme you used?

__________________________________________________________________________________

79

Investigate the effect of heat denaturation on the activity of an

enzyme


Procedure/Method:


80

Safety/Risks:

Labelled Diagram

Results:

Boiled Enzyme

Unboiled Enzyme

Height of Foam

Enzyme Active

Yes/No

Conclusion:

81

Skills for Heat Denaturation of Enzymes




Prepare the enzyme source Use the syringe, thermometer, graduated cylinder correctly Use the electronic balance accurately Set up and maintain the water baths Use the test-tube holder Use the timer

3. Observation Note the presence or absence of foam

4. Recording Write up the procedure Record the temperature each time Record the volume of foam Tabulate the results Draw a graph with labelled axes


6. Application Become aware of any other application(s) of what you learned in this activity for example different temperatures required for plant and animal enzymes to work

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label diagrams as appropriate Work in an organised and efficient manner Clean up after the practical activity

Hints for Denaturation • Enzyme preparations lose activity very quickly. Therefore, the enzyme extract must

be prepared immediately before use. • Liver is the best source of catalase but celery, radish and potato are also good. • If activity is high, e.g. when using liver, use larger cylinders.

82

Questions on heat denaturation and enzymes: 14. What is an enzyme?

__________________________________________________________________________________

__________________________________________________________________________________

15. Name the enzyme you used and give its source

___________________________________________________________________________

___________________________________________________________________________

16. Name the substrate for this enzyme

__________________________________________________________________________________

17. List 3 factors that affect enzyme activity

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________


__________________________________________________________________________________

__________________________________________________________________________________

19. How is each factor kept constant?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________


__________________________________________________________________________________

___________________________________________________________________________

21. Explain the biological basis for adding enzymes to some washing powders.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

22. Give a detailed account of how enzymes work, referring in your answer to their

specificity.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

83

23. During an experiment of temperature v rate of enzyme activity, the following results

were obtained. Temp. oC 10 20 30 40 50 60 70

Rate of reaction ml/min. 3 17 34 29 10 0 0

(i) Draw a graph for the above data on the graph paper below

(ii) What is the optimum temperature for the enzyme? __________________________________

(iii) Estimate, from your graph, the rate of reaction at 26OC. _______________________________

(iv)Estimate, from your graph, the temperature that yields a rate of 30ml/min of product. ______

Graph of temperature v rate of enzyme activity

Labelled Diagram

84

Prepare one enzyme immobilisation and examine its application


Procedure/Method: A: Preparing the Immobilised Enzyme


B: Application (Using the Immobilised Enzyme)


85

Safety/Risks:

Labelled diagram:

Results:

Free Enzyme Immobilised Enzyme

Time Taken for product to appear

Turbidity of Solution (Is it cloudy or clear?)

Conclusion:

86

Skills for Enzyme Immobilisation:

Skill Achieved 1. Following Instructions Familiarise yourself with all procedures before starting

Follow step by step method Listen to the teacher’s instructions


Use the balance and time Use a graduated cylinder to measure volumes Prepare solutions and mixtures Draw the mixture of alginate solution and yeast suspension into the syringe Release the mixture drop by drop into the calcium chloride solution Transfer the beads to the separating funnel Filter and rinse the beads with distilled water Set up the separating funnels Use a thermometer and a funnel Use glucose test strips to test for glucose

3. Observation Note the clarity of both sucrose solutions See beads forming Observe any colour change using glucose test strips Compare the turbidity of both end products

4. Recording Write up the procedure Draw a label led diagram Tabulate the results Record the time


6. Application Become aware of any other application(s) of what you learned in this activity for example in biotechnology

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Work in an organised and efficient manner Clean up after the practical activity

Hints for Enzyme Immobilisation

• Sodium alginate solution is best prepared by adding the powder to agitated water, rather than vice versa to avoid the formation of clumps.

• To avoid beads blocking the separating funnel, a plastic straw may be inserted into the funnel before adding the beads.

• Only use yeast which does not contain calcium sulphate.

87

Question on Enzyme Immobilisation:

1. What is meant by an immobilised enzyme?

__________________________________________________________________________________

__________________________________________________________________________________

2. Name one way that enzymes can be immobilised.

__________________________________________________________________________________

__________________________________________________________________________________

3. List the 3 chemicals / solutions you used in the experiment and explain the purpose of each.

(i)__________________________________________________________________________

(ii)_________________________________________________________________________

(iii)_________________________________________________________________________

4. Name the enzyme used and its source. ___________________________________________

5. What is the substrate of this enzyme? ____________________________________________

6. Name the product ____________________________________________________________

7. How did you test for the product? State any colour change involved.

__________________________________________________________________________________

8. Give two advantages of using immobilised yeast cells in the production of alcohol.

(i)__________________________________________________________________________

(ii)_________________________________________________________________________

9. What term best describes the shape of an enzyme?

___________________________________________________________________________

10. Lactose free milk is produced using immobilised enzymes. Name the substrate in this case.

__________________________________________________________________________________

88

Conduct any activity to demonstrate osmosis


Procedure/Method:


89

Safety/Risks:

Labelled diagram:

Results: Tube contents Turgidity at

start Turgidity after test period

Mass at start (g) Mass after test period (g)

Sucrose solution

Distilled water

Conclusion:

90

Skills for Osmosis




Soften the tubing in water Tie leak-proof knots Wash off excess sucrose Use the electronic balance Suspend the tubes from the rods

3. Observation Observe the appearance of the tubes at the start Observe the appearance of the tubes at the end of the test period

4. Recording Write up the procedure Tabulate results




Hints for Osmosis:

• Use visking tubing that is about 2 cm wide. • Treacle or golden syrup could be used instead of the 80% sucrose solution. • If using treacle or golden syrup, heat it in a beaker in a hot water bath to

decrease its viscosity. This makes it easier to add to the visking tubing bag. • Syringes could be used to fill the dialysis tubing bags. • Make sure to wash any sucrose solution off the knots.

91

Questions on Osmosis:

1. Define osmosis.

__________________________________________________________________________________

__________________________________________________________________________________

2. Define the term diffusion.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

3. Give an example of osmosis in plants

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________


__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

5. Suggest a reason for using distilled water rather than tap water.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

6. Where was the highest water concentration in your experimental set-up?

__________________________________________________________________________________

__________________________________________________________________________________

7. What represents a semi-permeable membrane?

__________________________________________________________________________________

__________________________________________________________________________________

92

8. Explain what is meant by semi-permeable membrane?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

9. Where was the highest solute concentration in your experimental set-up?

__________________________________________________________________________________

__________________________________________________________________________________

10. Osmosis is a passive process. Explain.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

11. Which substance moves through the cell by osmosis?

__________________________________________________________________________________

12. Water enters the outermost cells of the root by osmosis. What does this tell you about the cell sap of these outermost cells?

__________________________________________________________________________________

__________________________________________________________________________________

13. Osmosis has been described as a special case of diffusion. Explain why

__________________________________________________________________________________

__________________________________________________________________________________

93

Investigate the influence of light intensity on the rate of

photosynthesis


Procedure/Method:


94

Safety/Risks:

Labelled diagram:

95

Results:

Distance from

light source

(cm)

Light Intensity

=

10000/distance2

Trial 1

(No. of

bubbles/

minute)

Trial 2

(No. of

bubbles /

minute)

Average

(No. of

bubbles /

minute)

96

Plot a graph of Light Intensity (x axis) against Rate of Photosynthesis i.e. the number of bubbles produced per minute(y axis)

Conclusion:

97

Skills for Photosynthesis




Carefully use the scissors to cut the end of the plant Place the plant in the boiling tube, cut end pointing upwards Use the metre stick to measure distances of plant from light source Use the thermometer and the timer Use the light meter if you are using one

3. Observation After allowing the plant to adjust, observe a steady stream of bubbles Observe the number of bubbles being released per minute at each distance

4. Recording Write up the procedure Record the distance of the plant from the light source Record the number of bubbles being given off per minute at each distance Record the average number of bubbles being given off per minute at each of the given distances

Record the light intensity or 1/d2 Draw a graph with labelled axis



7. Organisation Exercise caution for your personal safety and for the safety of others Work in an organised and efficient manner Clean up after the practical activity

Hints for Photosynthesis • Use fresh elodea. Try out a few different sprigs of Elodea to see which one is bubbling best

and then use this one for the investigation. • Use a very bright light. • If the bubbles stop, or do not start, cut the stem again and lightly crush between your

fingers. • Keep the pondweed down at the bottom of the boiling tube. If the pondweed tends to

float, it can be weighed down with a paper clip.

98

Questions on Photosynthesis:

1. Give a balanced chemical equation for photosynthesis.

_______________________________________________________________________________

2. Complete the following table:

Requirement: Source:

Light

Carbon dioxide

Water

3. Where in the cell does photosynthesis occur?

__________________________________________________________________________________

4. The factors that affect the rate of photosynthesis include light intensity, temperature and

carbon dioxide concentration. In this investigation which factor will you vary, and how will you

vary it?

Factor:

__________________________________________________________________________________

How:

_________________________________________________________________________________

5. Which factors will you keep constant and how will you keep each of these constant?

Factor:

___________________________________________________________________________

How:

___________________________________________________________________________

Factor:

__________________________________________________________________________

How:

___________________________________________________________________________

6. How will you measure the light intensity?

__________________________________________________________________________________

99

7. Name the plant that you will use in this investigation.

__________________________________________________________________________________

8. Why will you use this plant instead of a land plant?

__________________________________________________________________________________

9. How did you prepare this plant before the experiment?

__________________________________________________________________________________

__________________________________________________________________________________

10. How will you measure the rate of photosynthesis?

__________________________________________________________________________________

11. Why will you place the plant in the water with the cut end of the stem pointing upwards?

_________________________________________________________________________________

12. Each time the light intensity is varied, the rate of photosynthesis cannot be measured

immediately. Why?

_________________________________________________________________________________

_________________________________________________________________________________

13. Explain how you calculated the rate of photosynthesis.

_________________________________________________________________________________

_________________________________________________________________________________

14. Is the experiment kept at a set temperature? Explain.

__________________________________________________________________________________

__________________________________________________________________________________

15. Suggest a way of keeping the plant at the bottom of a test tube during the investigation.

Why is it helpful to do this?

__________________________________________________________________________________

__________________________________________________________________________________

16. If the temperature of the water bath was increased to 45ᵒCelcius. Photosynthesis

would stop. Explain

__________________________________________________________________________________

__________________________________________________________________________________

100

Prepare and show the production of alcohol by Yeast


Procedure/Method: To produce alcohol using yeast


101

Safety/Risks:

Labelled diagram:

Procedure/Method: To show the presence of alcohol


102

Results:

Flask Original Colour of Filtrate

Final Colour of Filtrate Colour Changes

Yeast and Glucose Solution

Control ( no yeast)

Conclusion:

103

Skills for Production of Alcohol by Yeast




Use the graduated cylinder and syringe Use the electronic balance Attach the fermentation locks to the conical flasks Filter the suspension Set and maintain the water bath Use the timer

3. Observation Observe bubbles of carbon dioxide being liberated Observe the effect of filtering Observe colour changes Observe the presence/absence of yellow crystals

4. Recording Write up the procedure Draw a label led diagram Record any colour changes Record the presence/absence of yellow crystals


6. Application Become aware of any other application(s) of what you learned in this activity for example its use in the brewing industry

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Label diagrams as appropriate Work in an organised and efficient manner Clean up after the practical activity

Hints for production of alcohol by yeast

• Immobilised yeast may be used instead of dried yeast - this eliminates the need to filter. • In the iodoform test - Use commercial bleach and add sodium hydroxide if necessary. • Use pure ethanol to observe positive result in the iodoform test. • Use a cork borer when inserting tubing into bungs. • Using long necked conical flasks and setting the incubator at 25 °C would help to prevent

overflow during fermentation. • A Bunsen valve can be used instead of a fermentation lock during fermentation.

104

Questions on Production of Alcohol by Yeast:

1. Yeasts are eukaryotic organisms. What does this mean?

__________________________________________________________________________________

2. To which kingdom does yeast belong? _______________________________________________

3. Yeast cells produce ethanol in a process called: _________________________________________

4. Is this process affected by temperature? ______________________________________________

5. Name a substance that yeast can use to make ethanol. _________________________________ 6. What is the purpose of the glucose in this experiment?

__________________________________________________________________________________

7. What is the purpose of the yeast in this experiment?

_________________________________________________________________________________

_________________________________________________________________________________

8. At what temperature will the flasks be incubated at? ___________________________________

Give a reason for your answer.

__________________________________________________________________________________

__________________________________________________________________________________

9. State one advantage of using immobilised yeast in this experiment.

_________________________________________________________________________________

10. What substance, other than ethanol, is produced during fermentation? _________________________________________________________________________________

11. How could you test for carbon dioxide produced during fermentation?

__________________________________________________________________________________

12. Describe the control that you used in this experiment. __________________________________________________________________________________

__________________________________________________________________________________

105

13. Explain the purpose of a control in a scientific experiment. __________________________________________________________________________________

__________________________________________________________________________________

14. How did you know when fermentation was finished?

_________________________________________________________________________________

_________________________________________________________________________________

15. What chemical(s) did you use to test for the presence of alcohol?

_________________________________________________________________________________

16. Was heat needed in the experiment to test for alcohol?

__________________________________________________________________________________

17. State the colour changes that occurred when you tested for alcohol, if any:

_________________________________________________________________________________

18. Write a word equation for:

Anaerobic respiration in animals:

__________________________________________________________________________________

Anaerobic respiration in yeast:

__________________________________________________________________________________

19. Bioprocessing is often carried out using immobilised cells. Explain the underlined terms. __________________________________________________________________________________

__________________________________________________________________________________

106

Isolate DNA from a plant tissue


Procedure/Method:


107

Safety/Risks:

108

Labelled diagram:

Results:

Conclusion:

Note: Other fruits and vegetables can be used instead of an onion. Kiwis, strawberries are good.

Pineapple juice is a good source of protease.

109

Skills for Isolating DNA




Use the electronic balance Use the water bath, thermometer and timer Use the blender for the correct length of time Filter the mixture into a clean beaker Add the correct amount of protease to the filtrate Trickle the ethanol down the side of the boiling tube Draw out the DNA

3. Observation Accurately read the temperature of the water bath Observe two distinct layers of liquid after the addition of the alcohol Notice a change in viscosity at the interface of the two liquids Notice cloudy matter appearing at the interface of the two liquids Observe the appearance of the DNA

4. Recording Write up the procedure Record the result


6. Application Become aware of any other application(s) of what you learned in this activity for example the use of DNA analysis in forensics and epigenetics


Hints for Isolating DNA

• Some alternatives to onions are: tomatoes, peas, peaches, nectarines and kiwi fruits. • Use a cheap brand of washing-up liquid. However, it is important not to use the

bactericidal washing-up liquid as this causes the breakdown of DNA. • It is vital to blend for no more than three seconds. If the DNA appears fluffy, it was sheared

in the extraction process. It should appear as thin threads. • Industrial methylated spirits may be used as a cheaper alternative to ethanol. • If the DNA remains at the interface, place the boiling tube back into the ice bath. • Other sources of protease include fresh pineapple juice and contact lens solution

110

Questions on DNA:

1. What plant tissue did you use during this experiment? _________________________________

2. Where in a cell is DNA found? _____________________________________________________

3. In the above experiment, particular substances / methods were used to assist in the isolation of the DNA. Give a reason for each of the following:

Substance/Method Reason

Salt

Washing-up liquid

Chopping the plant material

60 degree water bath

Ice cold water bath

4. (i) Why is a blender used? ________________________________________________________________________________

________________________________________________________________________________

(ii) Why is it used for only 3 seconds?

__________________________________________________________________________________

__________________________________________________________________________________

5. Why is a coffee filter is used during the process instead of conventional filter paper? __________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

6.Why is protease used in this experiment?

__________________________________________________________________________________

__________________________________________________________________________________

111

7 The mixture was then filtered. After filtration, where was the DNA of your plant

tissue to be found?

__________________________________________________________________________________

__________________________________________________________________________________

8 How did you make the DNA visible? __________________________________________________________________________________ 9 What requirement is needed for the ethanol to work?

__________________________________________________________________________________

10 Describe how you removed the DNA from the test tube. _________________________________________________________________________________ 11 Explain each of the following terms in relation to DNA.

(i) Replication

__________________________________________________________________________________

__________________________________________________________________________________

(ii) Transcription

__________________________________________________________________________________

__________________________________________________________________________________

12 How are the two strands of a DNA molecule joined together?

_________________________________________________________________________________

13 What is ‘junk’ DNA?

__________________________________________________________________________________

112

Investigate the growth of leaf yeast using agar plates and controls


Procedure/Method:


113

Safety/Risks:

Labelled diagram:

Results:

Agar plate Appearance of colonies

Control

Plate with leaves

114

Draw the appearance of the dishes after 3 days

Experimental Dish Control Dish

Conclusion:

115

Skills for Leaf Yeasts

Skill Achieved 1. 2. Following Instructions

Familiarise yourself with all procedures before starting Follow your step by step method Listen to the teacher’s instructions


Label the plates Swab the bench Use the borer Sterilise the forceps and the cork borer Smear the petroleum jelly on the lid Seal the plates Invert and reinvert plates Use the thermometer and the incubator

4. Observation Observe the appearance of the colonies if present Observe any differences between the experiment and the control plates

5. Recording Write up the procedure Record the appearance of the experiment plate Record the appearance of the control plate


7. Application Become aware of any other application(s) of what you learned in this activity for example growing colonies of other fungi


Hints for Leaf Yeast Growth:

• Leaves from common ash, lilac, sycamore, red alder or hawthorn are generally suitable for use in this investigation. Ash leaves are particularly suitable.

• Take leaves from the base of long shoots as these are the older leaves and have been on the tree since spring and the yeasts have had time to colonise and grow.

• After collecting the leaves keep them in a rigid container e.g. a plastic box, to prevent the leaves being crushed and the leaf yeasts from being rubbed off.

• Take care not to get petroleum jelly on the side of the leaf discs from which the spores are to be collected.

• Leaves can be frozen in September and used at a later date

116

Questions on Leaf Yeast:

1. Name the plant you used during this experiment.

__________________________________________________________________________________

2. To which kingdom do yeasts belong?

__________________________________________________________________________________

3. Yeasts are eukaryotic organisms – what does this mean?

__________________________________________________________________________________

4. Distinguish between aseptic and sterile techniques in microbiology

__________________________________________________________________________________

__________________________________________________________________________________

5. Describe how you collected the leaf sample

__________________________________________________________________________________

__________________________________________________________________________________

6. What part of the leaf provided the spores? ____________________________________________

7. How did you ensure that the samples were all of similar size?

__________________________________________________________________________________

8. Agar on its own has no nutrient value. What nutrient was in the agar that you used?

__________________________________________________________________________________

9. Describe how you transferred the yeast to the nutrient medium.

__________________________________________________________________________________

__________________________________________________________________________________

10. Give three precautions you took to prevent contamination of the dishes while setting up the

leaves in the dishes.

(a) _______________________________________________________________________________

(b) _______________________________________________________________________________

(c) _______________________________________________________________________________

11. What control was used?

_________________________________________________________________________________

117

12.

i. How did you attach the leaves to the lid of the dish?

__________________________________________________________________________________

ii. What surface of the leaf faced the nutrient agar? _______________________________________

Why?

_______________________________________________________________________________

iii. Describe what you did after attaching the leaves to the lid.

__________________________________________________________________________________

__________________________________________________________________________________

iv. After incubation what did you observe in the control dish?

_______________________________________________________________________________

v. Give two words to describe the yeast you observed. _____________________________________

13. Yeasts are sensitive to air pollution. If sample A came from a clean air environment and sample B

came from a busy town. Which sample would you expect to yield few colonies and why?

Sample____________________________________________________________________________

Why?

__________________________________________________________________________________

14. How would you safely dispose of the used petri dishes from the above experiment?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

15. The petri dishes that you used are not opened to view the colonies. Why?

__________________________________________________________________________________

__________________________________________________________________________________

118

Prepare and examine microscopically the transverse section of a

dicotyledonous stem (x100, x400)


Procedure/Method:


119

Safety/Risks:

Labelled diagram:

Results:

Conclusion:

X 400 X 100

120

Skills for Preparing a TS of a Dicot Stem


Follow your step by step method Listen to the teacher’s instructions


Use the blade to cut the section Transfer sections using the paintbrush Use the dropper Manipulate the cover slip Use the microscope

3. Observation Observe the appearance of the sections under different magnifications Observe any differences between the sections

4. Recording Write up the procedure Draw and label a tissue plan


6. Application Become aware of any other application(s) of what you learned in this activity such as making TS of LS of other parts of a plant


Hint for Making a TS of a Dicot Stem • A simple microtome may be made from a nut and bolt. Almost remove the bolt from the

nut and fill the hole with hot wax. Place the sample in the wax and allow to cool. Then screw the bolt into the nut, raising the wax and allowing a thin section to be cut.

• Fresh green stems, with no secondary thickening, are easiest to cut. • Keep the stems wet, as turgid material is easier to cut thinly. Cutting under water can

also help with difficult specimens. • All cuts should be made at an internode. • A seeker may be used instead of a paintbrush to transfer the sections from the petri dish to

the microscope slide

121

Questions on Dicot Stem:

1. Define the term cotyledon.

__________________________________________________________________________________

__________________________________________________________________________________

2. Name a dicotyledonous plant _______________________________________________________

3. When using the light microscope, which objective lens will you first?

__________________________________________________________________________________

4. Why will you use a thin slice of stem?

__________________________________________________________________________________

__________________________________________________________________________________

5. Explain how you cut a thin section of stem

__________________________________________________________________________________

__________________________________________________________________________________

6. Name three tissue types in plants, giving the functions of each.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

7. If preparing a slide of a transverse section of a dicotyledonous stem, state the reason why you

used an herbaceous stem rather than a woody one.

__________________________________________________________________________________

__________________________________________________________________________________

8. Why was the stem cut between the nodes?

__________________________________________________________________________________

__________________________________________________________________________________

9. Name two of the tissues that are not vascular tissues.

__________________________________________________________________________________

10. Describe how you examined your section of stem with the microscope

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

122

Dissect, Display and Identify a Sheep’s Heart


Procedure/Method:


123

Safety/Risks:

Labelled diagram:

Results:

Chamber Size

small/large

Wall

thin/thick

Valve type Number of

flaps

Left atrium

Bicuspid

Right atrium

Tricuspid

Left ventricle

Semi-lunar

Right ventricle

Conclusion:

124

Skills for Dissecting a Sheep’s Heart


Follow step by step method Listen to the teacher’s instructions


Use the forceps, scissors and the scalpel Explore using the seeker Flag label the parts of the heart

3. Observation Appreciate the significance of washing the heart Observe the thickness of the left and right sides of the heart and the left and right ventricles Locate the ventral side of the heart Identify the coronary groove and the 4 chambers Observe the position of the main blood vessels Compare the different chamber sizes Identify the septum and the bicuspid valve Locate the chordae tendinae & papillary muscles Observe the tricuspid valve Note the positions of the blood vessels Identify the semi-lunar valve and the openings of the coronary arteries Locate the chordae tendinae and papillary muscles Observe the tricuspid valve Note the positions of the blood vessels going to and coming from the heart Identify the semi-lunar valve Locate the openings of the coronary arteries Examine the parts of the heart

4. Recording Write up the procedure Draw a labelled diagram


6. Application Become aware of any other application(s) of what you learned in this activity for example dissection of another organ


Hints for dissecting the heart: • To locate the blood vessels before cutting:

(a) Insert a rubber tube, attached to a tap, into part of the vena cava and gently turn on the tap. The water comes out through the pulmonary artery.

(b) Repeat this for the pulmonary vein. The water flows out of the aorta. • To show the pathway of blood through a coronary artery, you can inject a dye using a

plastic dropper. • To make flag labels use long pins and paper. Write with a pencil, as ink tends to run.

125

Questions on Heart Dissection:

1. How did you distinguish between the ventral (front) and dorsal (back) surfaces of the heart?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

2. How would you distinguish the left side from the right side of the heart?

__________________________________________________________________________________

__________________________________________________________________________________

3. Name the arteries through which the heart obtains its own blood supply. Are these arteries

visible in the dissected heart?

__________________________________________________________________________________

4. The heart contains cardiac muscle. Explain the meaning of the underlined term.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

5. What conclusions did you draw from the results obtained?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

6. What is the purpose of the semi lunar valve in the heart?

__________________________________________________________________________________

__________________________________________________________________________________

7. What separates the right side of the heart from the left?

__________________________________________________________________________________

8. Which chamber of the heart has the greatest amount of muscle in its wall?

__________________________________________________________________________________

126

9. Why is the wall of the left ventricle considerably thicker than that of the right?

__________________________________________________________________________________

__________________________________________________________________________________

10. What small openings can be found at the base of the aorta just above the semi-lunar valve?

__________________________________________________________________________________

__________________________________________________________________________________

11. Give reasons for the sterilisation of the dissecting equipment after dissection.

__________________________________________________________________________________

__________________________________________________________________________________

12. State the procedure that you followed to expose the semi lunar valve

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

13. Where in your dissection did you find the origin of the coronary artery?

__________________________________________________________________________________

14. State one way in which heart muscle differs from other muscles in the body.

__________________________________________________________________________________

_

127

Investigate the effect of exercise on the human pulse rate


Procedure/Method:


128

Safety/Risks:

Labelled diagram:

Results:

Before

exercise

Trial 1 Trial 2 Trial 3 Total Average

Resting

pulse rate

(beats/min)

Activity Standing Gentle

walking

Brisk walking Running

Pulse rate

(beats/min)

129

Conclusion:

Sit Gentle Walk Brisk Walk Run

Pulse

Rat

e (b

pm)

130

Questions on Pulse Rate investigation:

1. Name two sites on the human body where the pulse can be easily located.

(i)________________________________________________________________________________

(ii)________________________________________________________________________________

2. In which type of blood vessel (artery or vein) can the pulse be detected? Give a reason for your

answer.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

3. Why will you sit still for five minutes before commencing taking measurements?

__________________________________________________________________________________

__________________________________________________________________________________

4. Suggest a reason why you will measure your resting pulse rate three times.

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

5. What do you expect to happen to your pulse rate as you increase the level of activity?

__________________________________________________________________________________

__________________________________________________________________________________

6. Give a reason for your answer.

__________________________________________________________________________________

__________________________________________________________________________________

7. Why is it important that you take readings immediately after each stage of the investigation?

__________________________________________________________________________________

__________________________________________________________________________________

131

8. What factor will you keep constant during this investigation?

__________________________________________________________________________________

9. What factor will you vary during this investigation?

__________________________________________________________________________________

10. If it takes someone a long time to return to their resting pulse rate after exercise, what does this

indicate about their level of fitness?

__________________________________________________________________________________

__________________________________________________________________________________

11. The average rate of breathing of an adult at rest is: ______________________________. The

average pulse rate of an adult human at rest is: _______________________________

12. Complete the following by drawing a line through the incorrect term.

When you exercise, your breathing rate is faster / slower and is deeper / shallower. The lungs /

brain control breathing. When you exercise, you make more oxygen / carbon dioxide. The

amount of this gas builds up in the blood and the lungs / brain detect(s) the rise.

13. What is a pulse?

__________________________________________________________________________________

__________________________________________________________________________________

132

Investigate the effect of exercise on the breathing rate


Procedure/Method:


133

Safety/Risks:

Labelled diagram:

Results:

Before

exercise

Trial 1 Trial 2 Trial 3 Total Average

Resting

Breathing

Rate per min

Activity Standing Gentle

walking

Brisk walking Running

Breathing

rate

(breaths/min)

134

Conclusion:

Sit Gentle Walk Brisk Walk Run

Brea

thin

g Ra

te (b

reat

hs/m

in)

135

Questions on Effect of Exercise and the Breathing Rate:

1. Why will you sit still for five minutes before commencing taking measurements?

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

2. Why will you measure your resting breathing rate three times?

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

3. What do you expect to happen to your breathing rate as you as you increase the level of

activity?

_________________________________________________________________________________

_________________________________________________________________________________

4. Give a reason for your answer.

_________________________________________________________________________________

_________________________________________________________________________________

5. Why is important that you take readings immediately after each stage of the investigation?

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

6. If it takes someone a long time to return to their resting breathing rate after exercise, what does

this indicate about their level of fitness?

_________________________________________________________________________________

_________________________________________________________________________________

7. The average rate of breathing of an adult at rest is: _____________________________________

136

8. Name two sets of muscles used during inhalation.

_________________________________________________________________________________

_________________________________________________________________________________

9. Complete the following by drawing a line through the incorrect term.

When you exercise, your breathing rate is faster / slower and is deeper / shallower. The lungs / brain

control breathing. When you exercise, you make more oxygen / carbon dioxide. The amount of this

gas builds up in the blood and the lungs / brain detect(s) the rise.

137

Skills for measuring effect of exercise on Pulse and Breathing Rates




Use the timer Use the pulse rate meter or data logger if using

3. Observation Find a pulse or observe the breathing rate Observe the effect of exercise on the pulse and breathing rate

4. Recording Write up the procedure Record the pulse and breathing rate before and after various rates of exercise Tabulate results Draw a bar chart


6. Application Become aware of any other application(s) of what you learned in this activity for example the effect of exercise on your body temperature

7. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Work in an organised and efficient manner

Hints for measuring the effects of Exercise on Pulse and Breathing Rates

• It is not essential to undergo each level of exercise for this activity e.g. you may stop at brisk walking.

• The pulse can be felt at various points on the body where the arteries are just under the skin, such as the neck, and wrist.

• The thumb should not be used when measuring the pulse. The thumb has its own pulse and may confuse your count.

• Do not press too hard when feeling for the pulse or you may block it. • Heart recovery time can also be determined while doing this activity. After running, the

pulse is measured and recorded every minute until it returns to resting heart rate. The time taken to return to resting heart rate is known as the heart recovery time.

• To measure breathing rate: breathing in and out once is counted as one breath, so just count the out breaths. Do keep in mind that it is difficult to accurately measure the effect of exercise on breathing as there is a certain degree of voluntary control involved.

138

Investigate the effect of IAA growth regulator on plant tissue Date the experiment was completed: _________________ Materials/Equipment/Apparatus:

Procedure/Method:


139

Safety/Risks:

Labelled diagram:

140

Results:

Concentration

of IAA

(ppm)

Length of roots (mm) Total

Length

(mm)

Average

Length

(mm)

Percentage

stimulation

or inhibition Seed

1

Seed

2

Seed

3

Seed

4

Seed

5

0 (control)

10-4

10-3

10-2

10-1

1

101

102

141

Concentration

of IAA

(ppm)

Length of shoots (mm) Total

Length

(mm)

Average

Length

(mm)

Percentage

stimulation

or inhibition Seed

1

Seed

2

Seed

3

Seed

4

Seed

5

0 (control)

10-4

10-3

10-2

10-1

1

101

102

Result:

Conclusion:

142

Plot a graph of percentage stimulation and inhibition of root and shoot growth against IAA concentration. Put IAA concentration on the X axis and Average length or Percentage stimulation or inhibition on

the Y axis

143

Skills for Investigating the Effect of IAA




Use the syringes and the droppers Carry out a serial dilution Place the seeds on the acetate grids in the dishes Reduce the trapped air around the seeds Spread the cotton wool to absorb the excess solution Put the bases of the dishes in place Secure the dishes with adhesive tape Stand the dishes vertically Use the thermometer

3. Observation Observe the growths of the roots and the shoots Note the difference in lengths of the roots and the shoots in the different solutions

4. Recording Write up the procedure Record the length of the roots and the shoots Calculate the average length of the roots and the shoots Calculate the percentage average stimulation or inhibition of the roots or the shoots by each solution Tabulate the results Draw a graph with labelled axes


6. Application Become aware of any other application(s) of what you learned in this activity such as the effect of rooting powders on cuttings


Hints for Investigating the Effects of IAA • All the dishes containing the same concentration of IAA from the class may be supported in

separate one-litre plastic bottles as shown. • Make acetate grids by photocopying graph paper onto two acetate sheets.

144

Questions on IAA:

1. Name the plant that you used in this experiment _______________________________________

2. What is IAA?

_______________________________________________________________________________

3. What biomolecule would you equate IAA to in an animal? ________________________________

4. Name the plant you used in this experiment. __________________________________________

5. State the location in a flowering plant where a growth regulator is secreted.

__________________________________________________________________________________

6. Why is a control necessary?

__________________________________________________________________________________

__________________________________________________________________________________

7. Why are the acetate grids placed in each petri dish?

__________________________________________________________________________________

__________________________________________________________________________________

8. How would you make up serial dilutions of IAA?

__________________________________________________________________________________

__________________________________________________________________________________

9. How did you ensure that there was sufficient water for the seeds during the experiment?

__________________________________________________________________________________

__________________________________________________________________________________

10. What is a coleoptile?

__________________________________________________________________________________

145

11. Give an example of growth regulators that promotes and inhibit growth

__________________________________________________________________________________

__________________________________________________________________________________

12. The graph below shows the growth response of a stem and a root to varying concentrations of

auxin.

(a) At what concentration of auxin is there maximum root growth? ___________________________

(b) At what concentration of auxin is there maximum stem growth? __________________________

(c) What effect does 10-2 ppm have on root growth? _______________________________________

13. Name A in the diagram below _____________________________________________________

What is the purpose of A in this experiment? _______________________________________

How would you make up solutions of different concentrations from a stock solution of IAA?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

146

Investigate the effects of water, oxygen and temperature on

germination


Procedure/Method:


147

Safety/Risks:

Labelled diagram:

Results:

Dish Germination

A – with oxygen and suitable temperature (no water)

B – with water and oxygen (unsuitable temperature)

C – with water and suitable temperature (no oxygen)

D – with water, oxygen, and a suitable temperature

Conclusion:

148

Skills for Germination




Fill and empty the pipette Set up the water bath Use the test-tube holder safely Use the timer Label the tubes correctly Swirl the tubes

3. Observation Observe the appearance of the seeds at the start of the activity Check the seeds for germination Observe the effect of suitable/unsuitable conditions

4. Recording Write up the procedure Record the development of the seeds


6. Application Become aware of any other application(s) of what you learned in this activity for example the effects of external conditions on plant reproduction


Hints for Germination:

• Radish seeds are recommended, as they usually germinate after 24 hours in ideal conditions. • Some seeds are not easily available all year round. March/April is a good time to buy them. • The cotton wool only needs to be moistened, not saturated. • Ensure that the cotton wool is absorbent. • If access to an incubator is a problem, heating mats, which are available from plant

nurseries, can be used. In the event that neither is available, room temperature will suffice.

149

Questions on Germination:

1. Explain what is meant by seed germination.

__________________________________________________________________________________

__________________________________________________________________________________

2. Why is digestion necessary in a germinating seed?

__________________________________________________________________________________

__________________________________________________________________________________

3. Digestive activity during germination can be demonstrated by using agar plates.

What is an agar plate?

__________________________________________________________________________________

__________________________________________________________________________________

4. An extra food material is added to the agar plate for this demonstration.

Give an example of such an extra food material. _______________________________________

5. What control did you use for this experiment?

__________________________________________________________________________________

__________________________________________________________________________________

8. Describe the results that you obtained in:

1. The experimental plate.

__________________________________________________________________________________

2. The control plate.

__________________________________________________________________________________

9. Why should you cross-reference your results with other groups in the class?

__________________________________________________________________________________

__________________________________________________________________________________

10. Name another factor apart from temperature that might be different in a fridge, compared to

the other three dishes.

__________________________________________________________________________________

__________________________________________________________________________________

150

11. How many seeds are used in each petri dish for this investigation? Give a reason for the number

used

__________________________________________________________________________________

__________________________________________________________________________________

12. What result would you expect to observe after a few days?

__________________________________________________________________________________

__________________________________________________________________________________

13. Explain the need for water, oxygen and temperature during germination

Water:

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Temperature:_______________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Oxygen:___________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

14. Is it the air temperature or soil temperature that controls germination?

__________________________________________________________________________________

__________________________________________________________________________________

15. Give one location in a seed in which food is stored. ____________________________________

16. Name a carbohydrate that you would expect to be present in this food store

______________________________________________________________________________

______________________________________________________________________________

17. Explain the term embryo.

_______________________________________________________________________________

_______________________________________________________________________________

18. Seeds may remain inactive for a period before germination. What term is used to describe this

period of inactivity? _______________________________________________________

151

Use starch agar or skimmed milk plates to show digestive activity during germination


Procedure/Method:


Safety/Risks:

152

Labelled diagram:

Results: Starch Agar Plates

Unboiled: Test with iodine Boiled: Test with iodine Colour Under Seeds Give Description

Skimmed Milk Powder Plates

Unboiled: Test with Biuret Boiled: Test with Biuret Colour Under Seeds Give Description

Conclusion:

153

Skills for digestive activity in seeds




Use the thermometer Label the plates Boil the seeds Use the timer Split the seeds Sterilise the forceps and the seeds Transfer the seeds onto the agar Flood the plates with iodine solution/biuret reagent Pour off the excess iodine solution/biuret reagent

10. Observation Observe the difference between the control and experiment plates Observe the change in the starch/skimmed milk agar Observe the effect of iodine solution/biuret reagent Recognise the benefit of holding the plate up to the light

11. Recording Write up the procedure Draw a labelled diagram for apparatus

12. Interpretation Draw reasonable conclusions from your observations and results Appreciate the importance of leaving the plates for the appropriate time


14. Organisation Exercise caution for your personal safety and for the safety of others Work as part of a group or team Use aseptic technique throughout Work in an organised and efficient manner Clean up after the practical activity

Hints for Digestion of Seeds

• Pre-soak seeds for two days • Take care in moving the agar plates with the seeds, to prevent the seeds from sliding. • Label the tops and bases of the plates and keep the labelling small. • A blunt forceps is preferable to a sharp one as it is less likely to damage the seeds. • A forceps can be used to hold the seed in place while splitting it with the backed blade. • Have labelled petri dishes (‘Raw’ and ‘Boiled’) to hand when splitting the seeds.

154

Questions on digestive activity in seeds:

1. What type of agar plates did you use? ____________________________________________

2. How were the seeds placed on the petri dish?

___________________________________________________________________________

3. What aseptic technique did you use?

___________________________________________________________________________

___________________________________________________________________________

4. What reagent was used to investigate digestive activity? __________________________________

5. How did you dispose of the dishes once the experiment was finished? ______________________

__________________________________________________________________________________

6. In what form is carbohydrate stored in:

(i) humans: ___________________________ (ii) a broad bean: ______________________________

7. State where carbohydrates are stored in:

(i) humans: _________________________ (ii) a broad bean: _______________________________

8. Broad bean is a dicotyledonous, non-endospermic seed. Explain the underlined terms.

__________________________________________________________________________________

__________________________________________________________________________________

9. Maize is a monocotyledonous, endospermic seed. Explain the underlined terms.

_________________________________________________________________________________

10. During the digestive activity of the seed you used, state:

(i) Enzyme: ______________________________________________________________

(ii) Substrate: ____________________________________________________________

(iii) Product(s): ____________________________________________________________

155

Visuals for Experiments

Conduct a quantitative test for fat:

156

Visuals for Experiments

Conduct a quantitative test for protein:

157

Conduct a quantitative test for starch:

158

Conduct a quantitative test for reducing sugar:

159

Ecology - Some Animal Collection Equipment

Mammal Trap

Pitfall Trap

Pooter

Tullgren Funnel

Beating Tray

Insect Net

160

Ecology - Some Abiotic Measurement Equipment Quadrats

Air Thermometer

Soil thermometer

Hygrometer Anemometer

25 Point Grided Quadrat

Frame Quadrat

161

Be familiar with and use the light microscope:

162

Prepare and examine one animal cell using the light microscope:

164

Prepare and examine one plant cell using the light microscope:

166

Investigate the effect of pH on the rate of amylase activity:

168

Investigate the effect of pH on the rate of catalase activity:

170

Investigate the effect of temperature on the rate of catalase activity:

172

Investigate the effect of temperature on the rate of amylase activity:

174

Investigate the effect of heat denaturation on the activity of catalase:

176

Investigate the effect of heat denaturation on the activity of amylase:

178

Prepare one enzyme immobilisation and examine its application:

180

Investigate the influence of carbon dioxide concentration on the rate of photosynthesis:

183

Investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis:

185

Prepare and show the production of alcohol by yeast:

186

Conduct any activity to demonstrate osmosis:

188

Isolate DNA from plant tissue:

189

Investigate the growth of leaf yeast using agar plates and controls:

191

Prepare and examine microscopically the transverse section of a dicotyledonous stem:

192

Investigate the effect of exercise on heart rate:

193

Investigate the effect of exercise on breathing rate:

195

Dissect, display and identify an ox’s or a sheep’s heart:

197

Investigate the effect of IAA Growth regulator on plant tissue:

200

Investigate the effect of water, oxygen and temperature on germination12:

202

Use starch agar or skimmed milk plates to show digestive activity during germination:

203

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