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)