Year 10 Science

Doctor! Doctor!

Rāhinā te tekau ma rua Poutū-te-rangi.

• SLO’s & KW’s.

• Post box activity; what do we already know about the human body & nutrition?

SLO’s• Recall word equations for photosynthesis and respiration.• Describe the structure and role of different food types in

the body.• Relate the structure of different teeth to their function.• Give the names of the digestive organs.• Indicate where the parts of the human digestive system

are found in the body.• Describe the process of digestion occurring in the gut.• Test food samples to determine which food types are

present.• Identify the feeding role of a species.• Distinguish between different types of adaptations for

feeding.• Recall the different feeding relations found in a community.• Interpret food chains and food webs.• Outline how energy flows through an ecosystem.

Homework

• Keep a food diary for the next 3 days.

Rātū te tekau ma toru Poutū-te-rangi

• Key words 16.

• Check food diaries.

• Why do we need energy?

• What’s in our food?

You need energy!

• But where does the energy come from?

• Photosynthesis!

• CO2 + H2O + λ C6H12O6 + O2

Respiration

• The process of breaking down calories for energy (ATP).

A man walks into a bar and asks for a glass of energy.

The bar tender say’s “that will be 80p”.

C6H12O6 + 6O2 → 6CO2+ 6H2O + 2880 kJ

Food types

• Foods contain 4 main parts; carbohydrates, sugars, protein & fat.

• Different foods contain different proportions of each.

• Carry out the food test experiment to determine the contents of some foods.

Food groups.

• As a growing young person, a balanced diet now, will help you reach a healthy adult size.

• Good food choices become habit and set you up for life.

• Lets look at the food pyramid and your food diary.

Why must I eat all that green stuff?

• Carbohydrates (bread/cereal); energy

• Protein (meat/egg); muscle building

• Fat (oils); energy and to keep warm

• Vitamins (fruit/vege); needed to keep metabolism going.

• Calcium (dairy); bone strength

• Iron (meat); allows oxygen to move around the body.

Rāpare te tekau ma whā Poutū-te-rangi

• Keywords 712.

• Review food diary exercise.

• Calculate your daily intakes.

Caloric needs.

• Average Calorie Needs Each Day

• Boys 11-14 years; 2500

• Boys 15-18 years; 3000

• Girls 11-18 years; 2200

The exercise factor.

• The more you do, the more calories you need.

• Washing the dog 238 cal/hour

• Painting a wall 342 cal/hour

Now…

• Use your food diary’s to calculate your caloric intake and food groups.

• http://www.thecaloriecounter.com/

• How well did you do?

Rāmere te tekau ma rima Poutū-te-rangi

• QQ- keywords 712.

• Junk monkey’s; junk food & you.

• Homework-Ex 18.04

Food for thought.

• Lets look at the ‘Junk Monkeys’ programme.

http://www.youtube.com/watch?v=Bcqw5Uds378

Rāhinā te tekau ma iwa Poutū-te-rangi

• Mark homework Ex18.04

• Energy in a peanut experiment.

• How does your body use energy?

• What is a GI?

I want to know…

• How much chemical potential energy is contained in 1 honey roasted peanut.

• How might I find this out?

Energy in a peanut experiment.

Results

• Mass of water x rise in temp x 4.2

How does your body use energy?

• Your body must break the bonds between the atoms in your body, in order to access the chemical potential energy.

• Every time you break a bond, you released energy (respiration).

• The longer the molecular chain, the more energy you can gain from it.

• However, your body uses different foods in different ways.

G.I.

• The glycaemic index is a measure of how fast your body can use a certain food.

• Pure sugar can be broken down very fast as it is a small molecule.

• This means you gain short term energy.

• Long chains, such as proteins and complex carbohydrate, take much longer to break down.

• These give us sustained energy.

Time

Amount of energy

Coco popsWeetbix

What does this mean to us?

• A sugary cereal for breakfast, gives a short burst of energy, but we quickly use the sugar and soon we begin to feel tired & hungry.

• A cereal rich in complex carbohydrates, gives us a longer, slower flow of energy, so we feel fuller and more energetic until morning tea.

My personal crusade.

This cereal is sold to teenagers as a healthy option for breakfast; it is not (unless you are an actual triathlete).

It is packed full of sugar and the serving amount is 40g (about 1/2c), most teens end up eating 2-3 times that amount.

What has fewer calories?

• 2 cheese omelettes.

• 1 large piece of cake.

• Hash browns with ham & cheese, a glass of milk and a kiwifruit.

• A large waffle with berries & yoghurt.

• 2 banana muffins & a coffee.

Rātū te rua tekau Poutū-te-rangi

• Homework check.

• Food testing.

Food testing.

• We will now carry out an experiment to determine the starch, glucose, protein and fat contents, of 6 common foods.

• Test; bread, milk, biscuit, apple, potato and cereal.

Results

Food Starch Glucose Protein Fat

Bread X X X

Milk X X

Biscuit X

Apple X X X

Potato X X X

Cereal X X

Rāpare te rua tekau ma rua Poutū-te-rangi

• KW 712

• Analysis of the food experiment.

• Food 4 thought- game.

Carbohydrate foods.

• Bread & biscuit; wheat based.

• Cereal; rice based.

• Potato; store of starch for the plant.

Glucose foods.

• Biscuit & cereal; refined cane sugar.

• Apple; fructose sugar (naturally occurring in the fruit).

Protein foods.

• Milk; Casein protein.

• Meat; many different protein’s from an animal.

• Beans & legumes; complete proteins (all essential amino acids present)

Amount of energy

Time

Fat foods.

• Deep fried foods & high fat meats (bacon, sausage); high in saturated fats, not heart healthy.

• Natural fats; olive oil, nuts, heart healthy fats (unsaturated).

Rāmere te rua tekau ma toru Poutū-te-rangi

• Full keywords.

• The digestive system.

Right now you’ve eaten…

• What happens in digestion?

• http://www.school.ebonline.co.nz/lm/animations/odigesi001d4/product.html

• http://www.mhhe.com/biosci/genbio/virtual_labs/BL_16/BL_16.html

Step 1; teeth.

• Incisor; bite• Canine; rip & tear• Molar; grind• Tongue; form a ball of

food to swallow.

Step 2; the salvia.

• Three pairs of salivary glands are connected to the mouth. Their job is to release saliva. Saliva consists mainly of water and it moistens the food so that it sticks together in a ball called a bolus that can be easily swallowed. Saliva also contains an enzyme called ptyalin, which starts to break down starch into simpler sugars.

Step 3; the oesophagus.

• Once food is swallowed, it is carried down through the oesophagus to the stomach. The oesophagus is lined with muscles that contract to force food along. This is known as peristalsis.

Step 4; the stomach

• Swallowed food may spend up to several hours in the stomach. During this time, hydrochloric acid and the enzyme pepsin chemically digest the food. The hydrochloric acid is strong enough to kill any bacteria that may have been on the food. It also provides the acid conditions needed for pepsin to break proteins into amino acids.

Rāpare te rua tekau ma iwa Poutū-te-rangi

• Mark Ex18.03

• Digestive system continued…

Step 5; duodenum

• In the duodenum, bile from the liver and pancreatic juice from the pancreas are mixed with the food. Bile is slightly basic and so neutralises the stomach acid. It also breaks down lipids into tiny particles. The pancreatic juice contains three enzymes: amylase, which digests starch, trypsin, which digests proteins and a lipase which digests fats

Step 6; small intestine.

• Glucose, amino acids, some fatty acids and glycerol are able to diffuse through the walls of the small intestine and be absorbed into the bloodstream.

Villi

Step 7; large intestine.

• The material moving from the small intestine to the large intestine, or colon, contains a lot of water along with the indigestible materials. Water is removed from this material and reabsorbed by the body in the colon.

Step 8; rectum.

• The semi-solid material from the colon is stored in the rectum. This material is periodically passed out of the anus as faeces.

Rāmere te toru tekau Poutū-te-rangi

• Project time!

Project

• You are to create a PowerPoint presentation, describing the movement of food through the digestive system.

• You must explain what happens at each stage.

• Grades will also be given for your presentation of the PowerPoint to the class.

Rātū te toru Paenga-whāwhā.

• Complete the worksheet / mindmap to help you revise.

1 C

2 E

3 A

4 I

5 H

6 J

7 K

8 B

9 D

10 L

11 F

12 G

Q1

Answers.

• Q2. Energy in, energy out.

• How many calories should a 15 year old boy eat per day? 3,000

• How many calories should a 15 year old girl eat per day? 2,200

Q3. What are the 5 main food groups and how any serves should you have of each per day? Complete the food pyramid to answer the question.

Q4. Draw and describe the function of the 3 types of human teeth.

Incisor; biteCanine; rip & tearMolar; grind

• Q5. For each stage of digestion describe what happens to the food molecule.

• Ingestion: Food is chewed by the teeth, moistened with salvia and molecule begin to be digested.

• Digestion: Molecules are broken down.

• Absorption: Molecules pass into the blood.

• Assimilation: Molecules used in body chemistry.

• Egestion: Waste molecules pass from body.

Q6.

Q7. Food testing; complete the table.

Test Chemical Positive

Starch Iodine Blue-black

Glucose Benedicts Orange

Fat Water + ethanol

Cloudy

Protein NaOH + CuSO4 Purple

Q13.1 F

2 K

3 G

4 D

5 A

6 B

7 E

8 L

9 I

10 C

11 J

12 H

Rāpare te rima Paenga-whāwhā.

• Test day!

• Have a great holiday