northgate gcse science. knowledge organiser …name_____ teaching set_____ northgate gcse science....
TRANSCRIPT
Name_____________________________
Teaching set_______________________
Northgate GCSE Science.
Knowledge Organiser Biology.
This booklet contains questions from topics that are covered in
Biology. This is to be used throughout your GCSE to help you
consolidate your learning, and aid your revision. Use it to help
learn the definitions of common scientific terms. You can get
family members to test your knowledge, make quizzes, games
or flashcards.
As part of your homework mini quizzes will pop up during
lesson time based on the information inside this booklet.
The GCSE textbooks and other digital resources are available
online. www.Kerboodle.com. Your username is your initial and
surname e.g. jsmith and the institution code is po7. You may
also wish to use SAM learning for revision purposes.
Key to using this guide.
If you are entered into triple science you will need to know all of the knowledge
If you are entered into combined science you do not need to revise sections in bold.
If you are entered into combined science foundation you do not need to revise information
in italics.
B1- You and your genes.
1 What are gametes? Sex cells (e.g. eggs and sperm)
2 Name the form of cell division that
produces gametes.
Meiosis
3 Describe the cells produced by meiosis. There are four, haploid daughter cells that are
genetically different to each other.
4 What is a genome? A complete set of chromosomes/full set of DNA
5 Describe the structure of DNA Two strands in a double helix, joined together by
complementary bases with weak hydrogen bonds
between each other.
6 How do the bases in DNA pair up? Adenine with Thymine, Cytosine with Guanine (A with
T, C with G)
7 What is the complementary strand of DNA
if one strand has the base sequence
GTAATC?
CATTAG
8 What is a gene? A section of DNA with the instructions for making a
single protein.
9 When extracting DNA from fruit, what is
the role of the detergent solution?
It breaks down the membranes around the cell and the
nucleus.
10 When extracting DNA from fruit, what
substance is used to precipitate DNA?
(ice-cold) ethanol
11 What are alleles? Different versions of the same gene
12 What is an organism’s genotype? The alleles inside an organism (e.g. Bb).
13 What is a phenotype? What an organism looks like (as a result of its genotype)
14 Describe the genotype BB Homozygous dominant
15 State the sex chromosomes contained
within a male and a female body cell.
Male = XY. Female = XX.
16 Draw a Punnett square to show that your
chance of being born a girl was 50%
17 Define mutation. A change in a gene that results in a new allele.
18 When does mutation usually occur? During cell division.
19 How often will a mutation lead to a change
in the phenotype of an organism? Why?
Very rarely. Most characteristics are the result of more
than one gene.
20 What is the human genome project? A project to map all 3.3 billion complementary bases in
a full set of 46 human chromosomes.
21 State two ways that information about a
person’s genome could be useful in medicine?
1. Identifying their risk of developing certain diseases.
2. Identifying which medicines will work best for them.
22 What causes genetic variation? Sexual reproduction and mutation
23 What defines data for discontinuous
variation?
The data can only take a limited set of values (e.g.
colour, sex)
24 What do we call variation where the data
collected can be any value in a range?
Continuous variation
25 What name do we give the bell-shaped
curve that continuous data for variation
often forms?
A normal distribution
26 What happens to DNA if there is a point
insertion?
The inserted nucleotide will change the rest of the DNA
strand by shifting it along. The triplet codes will change
and the protein may not work.
27 What happens to DNA if there is a point
deletion?
The deleted nucleotide will change the rest of the DNA
strand by shifting it up. The corresponding triplet
codes will change, and the protein may not work.
28 What is a Eukaryote? It is a cell which has a nucleus to contain genetic
information, such as plants and animal cells.
29 What is a Prokaryote? It is a cell which does NOT have a nucleus to contain
genetic information, such as bacteria.
30 What are proteins? Proteins are strings of amino acids that perform specific
functions in an organism. They include enzymes and
structural proteins.
31 What are functional proteins? Those that carry messages or are receptors such as
hormones.
32 What are structural proteins? Those that give structure to the cells, such as collagen.
33 What determines which protein is made? A DNA triplet codes for a specific amino acid. The order
of bases in DNA, determines the order of the amino
acids.
34 How is a protein made? The two strand DNA unzips and acts as a template to
make mRNA.
mRNA then moves into cytoplasm
A Ribosome then reads the mRNA and attaches the
correct amino acids in sequence.
35 What is mRNA? Messenger RNA, single strand of nucleotides but
instead of thymine (T) like DNA it uses uracil (U), which
still pairs with adenine (A)
36 What is the structure of a DNA nucleotide? Phosphate, deoxyribose, base
37 What is the part of DNA called that does
not code for a protein?
non-coding DNA
38 What is cystic fibrosis? A genetic disorder caused by a faulty CFTR gene. It is a
recessive disorder.
39 What are the symptoms of cystic fibrosis? Causes problems with breathing and digestion, cells
make more mucus which blocks lungs. This causes
breathlessness and chest infections. Mucus blocks
enzymes from the pancreas so people cannot digest
their food properly and are short of nutrients.
40 What is an amniocentesis test? Amniotic fluid is taken using a syringe, it contains some
foetal cells.
41 What are the benefits and risks of
amniocentesis testing?
Risks - 0.5% of miscarriage, risk of infection, risk of
incorrect results. False positive and false negative
results
Benefits - Making informed decisions, getting support,
termination of pregnancy
42 What is a chorionic villus test? Cells removed from placenta, made from foetal cells,
2% change of miscarriage, almost no risk of infection.
43 What is a stem cell? Unspecialised cell that can divide and differentiate into
specialised cells.
44 What is genetic engineering? Modifying the genome of an organism to include
desirable characteristics
45 How do you put genes into new cells? 1. Isolate desired DNA and copy it many times.
2. Put the gene into a vector
3. Select cells that have successfully taken up the
vector and grow them on.
46 What is a vector? Used to transfer genes from one organism to another.
A Plasmid (small circular DNA), bacteria or virus can be
used.
47 What is a transgenic organism? An organism that has been modified to include genetic
material from another organism
48 What is PGD? Pre-implantation genetic diagnosis. A cell is removed
from each embryo and tested for harmful genetic
variants, a healthy embryo is then selected and
implanted in the uterus.
B2 - Keeping Healthy
1. What is a communicable disease? A disease caused by a pathogen that can be transferred
between organisms.
2. How could you prevent a communicable
disease from spreading?
Good hygiene to prevent contamination between
people or surfaces. Including effective sanitation,
keeping food in a fridge/freezer, good personal
hygiene, cooking food at correct temperature.
3. What is a non-communicable disease? A disease caused by a person’s lifestyle, environment or genes
4. What is a pathogen? An organism that causes a disease, including viruses,
fungi, bacteria and protists.
5. What is an antigen? A molecule or structure on the surface of a pathogen or
cell.
6. What is an antibody? A protein made to fight infection; each antibody
recognises one specific antigen.
7. What is the function of a white blood cell? To destroy pathogens.
8. State the two ways a white blood cell can
fight infection?
1. Ingest pathogens
2. Make antibodies to stick to the antigen, for the
pathogen to clump together or to tag it for ingestion.
9. What is the role of a memory cell? To remember how to produce specific antibodies to
fight infection from a specific pathogen.
10. What factors increase your chance of heart
disease?
Smoking, a diet high in fat or salt, a high BMI, stress.
11 What factors increase your chance of lung
cancer?
Smoking.
12. Draw a diagram to show how antibodies fit
an antigen.
13. Name types of physical defence in animals
and plants
Animals - skin, mucus and platelets
Plants - waxy cuticle, cell wall.
14. Name types of chemical defence in animals
and plants
Animals - stomach acid, enzymes in tear, mucus, saliva
Plants - antimicrobial substances are made in response
to infection
15. What is Influenza and how is it caused? It is a disease spread by a VIRUS. Spread in droplets of
body fluids, transferred from hands, eyes, mouth, nose.
16. What is Salmonella and how is it caused? It is a disease spread by a BACTERIA. It is spread by
contaminated food and water which is ingested.
17. What is athlete's foot and how is it caused? It is a disease caused by a FUNGUS. It is spread by skin
contact on contaminated surfaces
18. What is malaria and how is it caused? It is a disease caused by a PROTIST, spread by
mosquitoes which bite animals and introduce infected
saliva into the animal’s blood.
19. Why do you only catch some diseases
once?
Your immune system, specifically memory cells,
recognises the pathogen and responds more quickly by
producing antibodies.
20. What is meant by incubation period? The time it takes for the pathogen to multiply enough
to cause symptoms.
21. What is meant by an epidemic? A disease that affects many individuals in a population.
22. What is meant by a pandemic? A disease that spreads over a large area.
23. What is a carcinogen? A substance that can cause cancer by causing damage
to DNA in cells.
24. What is a STI? A sexually transmitted infection (disease) that is passed
from one person to another during sexual intercourse
by contact or exchanging bodily fluids. Can be caused
by viruses or bacteria.
25. What is acquired immune deficiency
syndrome?
AIDS is a disease which affects your body’s ability to fight infection. Caused by HIV (human
immunodeficiency virus)
26. What is the purpose of a vaccination? Vaccinations are given to prevent people or animals
suffering from an illness. Preventing the spread of
disease by herd immunisation.
27. How does a vaccination work? An inactive pathogen is given, by injection, nasal spray
or orally. The body’s immune system recognises the pathogen and produces antibodies. The memory cells
remember the pathogen and how to produce specific
antibodies. The vaccine does not cause the disease
because it is inactive although there may be side effect
for some people, and may not be suitable for everyone
to have.
28. What is herd immunity? Herd immunity works when a high percentage of the
population has been immunised. This protects the
whole community from the spread of a disease.
29. What is HPV? Human papilloma virus, it is a common STI and if
untreated can cause cervical cancer.
30 Describe type II diabetes A person does not produce insulin or no longer
responds to it. Which causes blood sugar levels to rise.
The risk of developing diabetes is increased by obesity.
31. Why would you be prescribed antibiotics? To kill off bacteria from an infection.
32. Describe why is it important to finish the
full course of antibiotics?
Overuse or misuse of antibiotics increases the rate of
development of resistant strains of bacteria. Resistant
bacteria become more common, especially as there will
be less competition for space and nutrients. Over time
antibiotics become less effective.
33. What is cancer and what factors increase
your chance of developing cancer?
Cancer is the uncontrolled division of cells; risk factors
include genetics, the environment (exposure to
carcinogens, including cigarettes and asbestos) and
lifestyles (obesity).
34. How are new medicines developed? Identify a target for the drug. Find a chemical that will
have the desired effect on the target (stop an enzyme
from working, stop cells from dividing by interrupting
DNA replication). Chemical libraries can be used to
screen for useful chemicals. Most promising are
selected and modified. Cycle repeats until a useful
chemical is made. Medicine undergoes pre-clinical trials
on human cultured cells and then live animals to test
for safety and effectiveness.
35. Describe the three types of clinical trial
that are carried out before a new drug is
approved
Blind study - patient doesn’t know if they are receiving the drug or placebo (no bias from patient).
Double blind study - doctor or patient doesn’t know if they are receiving the drug or placebo (no bias from
doctor or patient).
Open label – both the patient and doctor are aware
(used when comparing drugs).
36. Describe the process and results of Gram
staining.
Gram staining is a way of identifying bacteria. A dye
added to bacterial cultures, the bacteria will be
classified as Gram positive or Gram negative.
37. Why are cell cultures made from samples? To increase the number of cells so that diagnostic tests
can be carried out.
38. What is a gene probe? A short piece of single stranded DNA, which will pair
up with a particular target. The probe can be joined to
a fluorescent molecule to aid detection by a computer.
49. Describe how monoclonal antibodies are
made
An organism (mouse) is injected with the antigen.
White blood cells in the mouse produce the antibodies
against it. A blood sample is taken and the cells
making the antibody are extracted, then fused with a
tumour cell to produce more antibodies.
B3 - Living Together, food and ecosystems
1. What is a producer? An organism that produces its own food (plants)
2. Name the process that plants use to make
food.
Photosynthesis
3. Give the word equation for photosynthesis carbon dioxide + water → glucose + oxygen
4. Give the chemical equation for
photosynthesis
6CO2+ 6H2O → C6H12O6 + 6O2
5. Where does photosynthesis take place? In the leaf of a plant, in organelles called chloroplasts.
They contain a pigment called chlorophyll that
absorbs light and splits water into hydrogen and
oxygen.
6. Describe why photosynthesis is an
endothermic process
Solar energy is required to produce glucose. The
products have more energy in their bonds than the
reactants.
7. Describe how could you measure how light
intensity affects the rate of photosynthesis
Place some pond weed in a boiling tube, within a
beaker of water. Attach a syringe to the boiling tube
to collect gas given off during photosynthesis. Place a
lamp at a distance away from the pond weed and
measure the amount of gas given off. Repeat, but
changing the distance of the lamp.
8. What is the inverse square law? The light intensity at any distance from a light source
is inversely proportional to the square of the distance
from the light source. LI = 1/𝑑2
9. Why does the rate of photosynthesis plateau? As the rate of photosynthesis is determined by light
intensity, carbon dioxide and water. Whichever
substance is in short supply will limit the rate - the
limiting factor.
10. What two word phrase best describes
enzymes?
Biological catalyst
11. What is the uniquely shaped ‘pocket’ on the outside of an enzyme called?
The active site
12. What do we call substances that fit into the
active site for enzymes to work on?
Substrates
13. Which model explains how enzymes work? Lock and key model
14. State three conditions that might affect the
rate at which an enzyme works.
Temperature, pH and substrate concentration
15. Which two conditions could affect the shape
of an enzyme’s active site?
Temperature and pH
16. How do we describe an enzyme whose active
site has changed shape, so it no longer
works?
Denatured
17. Name the process by which substances move
from an area of high to an area of lower
concentration.
Diffusion
18. Name the process by which water molecules
moves across a semi-permeable membrane
from an area with low solute concentration
to an area with high solute concentration.
Osmosis
19. Name the process by which substances move
from an area of low to an area of higher
concentration.
Active transport
20. What process do root hair cells use to absorb
water?
Osmosis
21. What is osmosis? The movement of water molecules from an area of
higher concentration to an area of low concentration
through a partially permeable membrane
22. What drives transpiration? Water loss from leaves due to evaporation
23. How are minerals taken up by the plant? Active transport at the roots
24. Describe how a plant takes in water from the
soil.
· into the root hairs
· through a partially permeable membrane
· by osmosis
· down a concentration gradient
25. How are root hairs adapted to take up water? Long thin extensions reach into the soil – this gives a
large surface area for substances to enter the root.
26. How can we tell that photosynthesis is taking
place?
Testing the plant for the production of starch, by
adding iodine, if it turns black starch is present.
27. Describe the structure and function of the
xylem
Xylem is made of dead cells joined end to end to make
one continuous tube. Its function is to transport
water from the roots to the leaves
28. Describe the structure and function of the
phloem
Phloem is made of living cells joined end to end to
make one continuous tube. Its function is to transport
sugars (food) and nutrients, up and down the stem.
29. Describe the process of translocation Sugars made in the leaf move into the phloem (active
transport), water then moves into the phloem
(osmosis). An increase in pressure causes the
substances to move along the phloem, where sugar is
then unloaded in the sink (roots, stem or flowers).
30. What is a consumer? An organism that gets its food by eating another
organism.
31. What is biomass? Mass of a biological nature.
32. What does the arrow show in a food
chain/web?
Transfer of biomass between the trophic levels.
33. What is interdependence? The size of a population of organisms effects, and is
affected by, the sizes of other populations in an
ecosystem, e.g. feeding relationships.
34. What things might organisms compete for? Food, water, space, light, shelter, mates, pollinators,
seed dispersers.
35. What is a pyramid of numbers? Each bar represents the number of organisms in each
trophic level.
36. What is a pyramid of biomass? Each bar represents the mass of organisms in each
trophic level.
37. How do you calculate the efficiency of
biomass transfer?
efficiency = average biomass in higher trophic level
x100
average biomass in lower trophic level
38. Describe the difference between abiotic and
biotic
Abiotic is a non-living part of a system, biotic a living
part.
39. Which process removes carbon from the
atmosphere?
Photosynthesis
40. How is carbon returned to the atmosphere? Respiration, combustion, volcanic activity.
41. What is decomposition? The process in which dead organisms are broken
down and substances in their bodies returned to the
environment.
42. What conditions are required for
decomposition?
The correct temperature, water and oxygen.
43. Describe how to calculate the rate of
decomposition?
rate of decomposition (g/day)= change in mass (g)
number of days
44. What is a habitat? The place an organism lives
45. Describe bioaccumulation An increase in the concentration of a substance
(toxins) in organisms in the higher trophic level of a
food chain.
46. What is eutrophication? Environmental damage where excess nitrate or
phosphate in water causes rapid algae growth,
blocking out light. The resultant death and
decomposition of water plants leads to a reduction in
oxygen levels, and death of water animals.
47. How would you investigate the distribution
and abundance of plant species in two areas?
Random sampling using a quadrat
48. What method would you use to investigate
how a change in an abiotic factor affects the
distribution and abundance of a species?
Systematic sampling using a transect and quadrat
49. How would you measure the distribution and
abundance of a species in a river?
Kick sampling.
50. How would you estimate the population of
an animal species in an ecosystem?
Capture - mark - recapture.
estimate population= no in 1st sample(marked) x no
in 2nd sample
number in second sample
marked
51. What is an indicator species? A species whose abundance can be used to indicate
the levels of pollution in an area
B4 - Using food and controlling growth
1. Give the word equation for respiration glucose +oxygen → carbon dioxide + water
2. Give the balanced symbol equation for
respiration
C6H12O6 + 6O2 → 6CO2+ 6H2O
3. What is ATP, how is it made and what is it
used for?
ATP is made during respiration, it is a molecule used
to carry out essential processes, including muscle
contraction, active transport and other chemical
reactions.
4. Describe aerobic respiration Respiration in the presence of oxygen
5. Describe anaerobic respiration Respiration that occurs without the presence of
oxygen.
6. Give the word equation for anaerobic
respiration in animals
glucose → lactic acid
7. Give the word equation for anaerobic
respiration in plants and yeast.
glucose → ethanol + carbon dioxide
8. When is anaerobic respiration in plants,
yeast and bacteria useful?
When we use it to make alcohol, bread, yoghurt and
cheese.
9. Define fermentation The process of yeast cells carrying out anaerobic
respiration. Usually referred to when making food
products.
10 How could you record and calculate the rate
of respiration?
By collecting the gas product in a cylinder or gas
syringe and measuring the time taken.
The rate of change = change in volume gas (cm3)
time taken for change (s)
This can also be compared in a graph format. By
comparing gradients of the line of best fit.
11 How do you calculate total magnification Magnification of eyepiece lens x magnification of
objective lens
12 What is high resolution? An ability to see details that are very close together
13 What is depth of field? When an object is focused, objects above or below
the focus appear blurred.
14 Compare a light microscope and an electron
microscope
Light microscope - resolution is limited by the nature
of light so the best ones can only review objects as
small as 0.2㎛. They can only focus on one object as
depth of field is low. Cheaper, portable.
Electron microscope - resolution is higher, up to x
500 000 magnification. Greater depth of field allow
for surface of specimen to be scanned, and 3D
imaging. Expensive and not portable.
15 What is a unicellular organism? An organism of just one cell
16 What is a multicellular organism? An organism made of many cells.
17 Explain the cell cycle A cell will spend most of its time in interphase - the
cell grows larger, organelles are copies and each
chromosome is copied.
Then the cell undergoes mitosis - where cell division
occurs so that two new identical cells are produced.
18 Describe the process of mitosis The nuclear membrane breaks down.
The copied chromosomes line up in the middle of the
cell.
The chromosomes separate so that one of each is at
either end of the cell.
New nuclear membranes develop to create two
nuclei.
The cell pinches in the middle (cytokinesis) to form
two new identical cells with organelles.
19 What is a tumour? A ball of cells which has been created by cells
undergoing uncontrolled mitosis.
20 Describe the process of fertilisation When two gametes containing genetic information
join together, forming the first cell of a living
organism (zygote).
21 How many chromosomes are in a human
body cell and human gamete cell?
Human body cell - 23 pairs
Human gamete - 23
22 What process is responsible for the
production of gametes?
Meiosis
23 Describe the process of meiosis. A normal cell undergoes interphase, duplicating its
chromosomes.
There are two sets of divisions.
The first division gives two cells with 23 pairs of
chromosomes.
The second division gives four cells with 23
chromosomes.
The process is random to increase genetic variation.
24 What are embryonic stem cells? The zygote contains the exact copy of the original
DNA. Up to 8 cell stage they are all unspecialised and
have the potential to become any cell type.
25 What is differentiation? The process of a cell becoming specialised to carry
out a specific job. This happens by genes being
switched off.
26 Describe gene switching Every cell nucleus has the genes for every protein.
However not every cell requires all of the proteins.
Different genes switch off in different cell types,
however some genes, such as those for respiration,
always remain on.
27 What is an adult stem cell? Stem cells in adults that are able to differentiate into
a small number of different cell types. Such as in the
skin, liver and bone.
28 What is the role of meristem cells in plants? To increase the width of roots and stems. They can
also grow new xylem, phloem and leaves if the area
gets damaged. Which is how we take cuttings of
plants to grow new identical plants.
29 What is phototropism and what causes it? Plants respond to light using hormones
30 What is gravitropism and where does it
happen?
A plant responds to gravity in roots
31 How do auxins cause shoots to curve
towards the sun?
Auxin moves to shaded side and causes elongation
of cells in the shoot, this only happens on one side
of the shoot causing shoot to curve
32 Name another plant hormone used in
germination
Gibberellin
33 Name four uses of plant hormones Selective weed killers
Rooting powder
Seedless fruit
Fruit ripening
34 Give examples of the application of stem cell
treatments
Applications are still in clinical trials but include the
ability to treat blood disorders, diabetes, spinal cord
and brain damage.
35 What are the risks of stem cell treatments? Infections from operations or infected cells.
Tumours
Organ damage
Immune rejection (when stem cells have come from
a donor)
36 Describe graft-versus-host disease New bone marrow from a donor produces new white
blood cells that do not recognise the patient as “self” and start attacking the patient’s body cells.
B5 - The Human body, staying alive
1. What is the structure and function of the
alveoli?
They are tiny sacs in your lungs that fill with air
when you inhale.
It is the surface of gas exchange where oxygen
diffuses into the capillaries and carbon dioxide
diffuses from the blood plasma in order to be
exhaled out.
2. Put these words in order of smallest to largest-
Organ, organism, organ system, cell, tissue
Cell, tissue, organ, organ system, organism
3. List the four main blood vessels associated with
the heart
Pulmonary artery, pulmonary vein, aorta and
vena cava
4. What do the left atrium and ventricle do? Pump oxygenated blood around the body
5. What to do the right atrium and ventricle do? Pump deoxygenated blood to the lungs
6. What do the valves do? Prevent backflow
7. Which ventricle has the thicker muscle Left
8. What is the role of the arteries, and how are
they adapted to the role?
Transport blood from the heart to organs that
need it, They have a thick layer of muscle and
elastic fibers to withstand high pressure of blood.
9. What is the role of the veins, and how are they
adapted to the role?
Transport blood to the heart, thin layer of muscle
and elastic fibres as blood is at low pressure.
Larger lumen and valves to stop the blood
flowing backwards.
10. What is the role of the capillaries, and how are
they adapted for this role?
Exchange materials with tissues. They have thin
walls only one cell thick which allows exchange of
molecules more efficiently.
11. Describe the shape of a red blood cell It is biconcave
12. What do red blood cells do? Transport oxygen and carbon dioxide
13. How are red blood cells adapted? biconcave disc shape gives it a large
surface area to volume ratio for oxygen to
diffuse into and out of the cell
has no nucleus – this makes as much
room for haemoglobin and oxygen as
possible
14. What does the haemoglobin in red blood cells
do?
combines reversibly with oxygen
combines with oxygen in the lungs to
become oxyhaemoglobin
releases oxygen to the tissue cells for
aerobic respiration
15. Describe how the circulatory system transports
substances around the body.
● arteries / aorta transport blood away
from heart
● veins / vena cava transport blood to the
heart·
● capillaries exchange materials with
tissues / cells
● substances carried in plasma / oxygen
carried in red blood cells
16. What does plasma do? Liquid part of blood that transports glucose,
hormones, waste and dissolved CO2 around the
body, helps to disperse heat around the body.
17. Describe what a receptor is and give some
named examples.
A receptor detects a change in the environment
and includes nerve receptors in skin and sensory
organs (ear, nose, eye)
18. Give an example of an effector and describe its
role
To enable the body to respond to a stimulus, for
example muscles to make the body move away
from pain, muscles in the eye to contract the
lens, glands to secrete hormones.
19. What is the central nervous system (CNS)? The brain and spinal cord
20. What is the peripheral nervous system (PNS)? The nerves around the body that connect
effectors and receptors to the central nervous
system.
21. Draw and label a picture of a neuron.
22. Describe how a neuron is adapted for its
function
The axon is long and thin to connect over long
distances.
The fatty sheath wrapped around the axon
increases the speed of the impulse.
23. What is the difference between sensory and
motor neurons?
Sensory neurons carry nerve impulses from
receptors to the CNS.
Motor neurons carry nerve impulses from the
CNS to effectors.
24. What is the gap between neurons called? Synapse
25. How do nerve impulses cross a synapse? Molecules of transmitter substances are secreted
from one neuron, diffuse across the synapse, fit
into a receptor on the membrane of the next
neuron then reabsorbed by the first neuron to be
used again.
26. What is a reflex response? A response from a stimulus that happens
automatically.
27. Describe a reflex arc. It is used in simple reflexes where the nerve
impulse is connected to a relay neuron in the
spinal cord, which links to a motor neuron
without the need to link to the brain.
28. What is the function of the brain stem? To control your heart rate and breathing rate
29. What is the cerebral cortex responsible for? Consciousness, intelligence, memory and
language.
30. What is the cerebellum responsible for? Conscious movement.
31. What is a functional MRI (fMRI)? A scan that gives detailed information about the
brain structure and function, they show which
parts of the brain are most active when patients
are given differing tasks.
32. What is an advantage of fMRI? The brain can be studied without the need to
open the skull or experimenting on animals.
33. How are hormones transported? In the blood
34. What is the role of the pituitary gland? It makes hormones that control other glands.
35. What is thyroxine? A hormone secreted by the thyroid gland, it
regulates growth and metabolism.
36. What is adrenaline? A hormone secreted by the adrenal glands, it
increases heart rate and breathing rate, increases
the rate of glucose production and stimulates
muscle contraction.
37. Describe negative feedback with respect to the
thyroid gland
As the pituitary gland produces TSH (thyroid
stimulating hormone) it switches on production
of thyroxine from the thyroid gland, thyroxine
then switches off production of TSH.
38. What is homeostasis? The maintenance of an internal environment
39. What it the role of the hypothalamus in the
brain?
It has receptors to detect temperature changes
in the blood. If the temperature is above or
below 37 oC, nerve impulses are sent to
effectors.
40. How does your body cool down? Nerve impulses stimulate sweat glands.
Vasodilation is the widening of arteries to
increase blood to the skin, making you look red
but heating the surroundings to cool your blood.
41. How does your body warm up? Vasoconstriction narrows the arteries to limit
the blood flow at the skin.
Erector muscles cause the hair on your skin to
stand up to trap warm air
Shivering increases cellular respiration to
increase heat in the surrounding tissues.
42. What is the role of the kidneys? Blood passes through to be filtered; water and
urea pass through into the kidney tubules to
make urine, which is sent to the bladder.
They control the amount of water in your body
(water balance) by adjusting the concentration
of urea in urine.
43. What is the process of puberty? The process that changes a child’s body into an adult.
44. What is oestrogen? A female hormone that causes the thickening of
the lining of the uterus and growth of breasts.
45. What is testosterone? A male hormone that causes growth of penis and
growth of tissues in testes that make sperm.
46. Describe the menstrual cycle Day 1 - menstruation, the lining of uterus starts
to shed.
Day 14 - ovulation, the ovum is released from the
ovary.
Day 16-28, uterus thickens to receive fertilised
ovum (zygote). If ovum is not fertilised it dies and
the cycle starts again.
47. What is the role of follicle-stimulating hormone
(FSH)?
Causes a follicle to mature and ovaries to secrete
oestrogen.
48. What is the role of luteinising hormone (LH)? Causes ovulation.
49. What is the role of progesterone? Prepares the uterus lining to receive fertilised
ovum and stops secretion of FSH and LH.
50 Describe how the contraceptive pill works. The pill is used to prevent pregnancy only (not
sexually transmitted infections).
Contains combinations of hormones that disrupt
the menstrual cycle.
Progesterone pill will stop secretion of LH, so
ovulation does not happen.
51. How does insulin regulate blood glucose levels? Causing excessive blood glucose to be converted
to glycogen and stored in the liver
52. How does glucagon regulate blood glucose? It causes glucagon in the liver to be converted
into glucose
53. What causes type 1 diabetes? Lack of insulin
54. How can type 1 diabetes be managed? Control of diet and injection of insulin into
subcutaneous fat
55. How does the level of physical activity and diet
affect the level of insulin required?
More exercise and less sugar in diet both reduce
blood glucose so less insulin (and vice versa)
56. What is type 2 diabetes? A person becoming resistant to insulin
57. How can type 2 diabetics control their blood
glucose using diet and physical activity
More exercise and less sugar in diet both reduce
blood glucose
58. Which type of diabetes is linked to obesity? Type 2
59. Draw a diagram of the human eye.
60. Describe how the eye works The iris changes size to adjust the amount of
light entering the eye.
The cornea and lens refract the light to focus
the light on the back of the eye (retina)
The retina is a layer of light receptor cells called
rods and cones, which transmit nerve impulses
to the brain via the optic nerve.
61. What is a cataract? A cloudy patch that forms in the lens. This can
cause blurred vision
62. What is meant by being long sighted? Distant objects are seen clearly and near objects
appear blurry.
The lens cannot become round enough to focus
light from near objects.
Treated by wearing a convex lens.
63. What is meant by being short sighted? Distant objects are seen blurred and near
objects seen clearly.
Treated by wearing a concave lens.
B6- Life on Earth the past, present and future.
1 What is the definition of a species? A group of organisms that can breed to produce fertile
offspring.
2 How is natural selection believed to
explain evolution?
When individual organisms are better adapted to their
environment they are more likely to survive and
reproduce, passing on characteristics to the next
generation.
3 What factors might lead to variation
between individuals within a species?
Environmental factors and genetic changes or
mutations.
4 What is selective breeding? The process whereby humans choose organisms with
certain characteristics and mating them to try to
produce offspring with favourable characteristics.
5 What are domesticated animals? Animals that have been selectively bred to live and
work with humans.
6 What is a transitional species? A species that shows some features of an older species
and some of a newer species. Fossil records of
transitional species show one possible way that the
newer species may have evolved from the older one.
7 What is a common ancestor? When traced back, species have evolved from the same
organisms. It is thought that life on Earth began with
very few simple organisms.
8 Give a modern example of evolution Head lice - As people have been killing head lice, a few
survived, they bred and passed on to their offspring the
resistance to the poisons used to kill them. The change
of environment of the head lice caused natural
selection.
MRSA - As people take antibiotics to kill bacteria, a few
survived and replicated, the offspring have same
resistance.
9 How was classification of species decided
in the past?
Based on external and internal structures, if the
organism produces its own food, the environment and
habitat.
10 How is classification of species decided
more recently?
Along with traditional ideas, cell structure and DNA
analysis
11 Name the 3 domains Bacteria, Archaea and Eukaryotes
12 Name the 6 kingdoms Bacteria, Archaea, Protists, Fungi, Plants and Animals.
13 What is biodiversity? The vast variety of organisms that live in an area
14 Describe how humans have a negative
impact on biodiversity.
● Changing or destroying habitats.
● Removing or killing organisms
● Introducing organisms that do not belong there,
such a pathogens or predators
● Pollution or contaminating the local
environment
● Global climate change
15 Explain the term deforestation and its
impact on the global environment.
Deforestation is the cutting down of trees on a large
scale. Destroying the local ecosystem and decreasing
the amount of carbon dioxide taken up by
photosynthesis. It increases the amount of greenhouse
gas in the atmosphere and contributes to global
warming.
16 Explain the term soil erosion and its
impact on the local environment.
Soil is removed by rainfall transported into rivers and
oceans. So there is less fertile soil available for plants
and crops. Tree roots help to prevent soil erosion.
17 What is the definition of biodegradable? Substances that can be broken down by
microorganisms such as bacteria and fungi.
18 Give an example of a biodegradable
substance and one which is not
biodegradable.
Biodegradable - wood, paper, cotton
Non-biodegradable - plastics
How science works
1. What is meant by an outlier? It is a value that is not expected and is caused by
random errors. The reading should be taken again or
not used during calculations.
2. What is meant by accuracy? Describes how close the result is to the true value
3. What is meant by precision? Describes the measure of spread in the data, a small
spread is more precise.
4. What is the independent variable? The variable that we change in an experiment
5. What is the dependent variable? The variable that is measured.
6. What is a control variable? The variable that is kept the same to allow comparisons
of the data collected.
7. What is a random error? A source of variation in the measurements that cannot
be avoided.
8. What is a systematic error? An error that is the same in all data and repeated. Good
examples include using uncalibrated equipment.
9. How should you measure liquids
accurately?
By taking the measurement from the bottom of the
meniscus (bubble).
Equipment such as a burette, glass pipette and filler
and a volumetric flask are more accurate than beakers
and measuring cylinders.
10 What is the standard unit (SI) of:
mass
length
time
temperature
area
volume
BMI
Light intensity
kilogram (kg)
meters (m)
seconds (s)
degrees Celsius (oC) or Kelvin (K)
meter squared (m2)
meter cubed (m3) or decimeter cubed (dm3)
kilogram per meter squared (kg/m2)
Watt per meter squared (W/m2)