AQA GCSE Biology - Paper 1 Question
and Answers 2024/2025
Adaptations of Exchange Surfaces
-- Correct Answer –
a) large surface area - lots of substances can diffuse at once
b) Lots of blood vessels - to get stuff into and out of the blood quickly
c) thin membrane - short distance for substances to diffuse
d) Often ventilated - air moves in & out
Aerobic respiration
-- Correct Answer --Respiration using oxygen
Goes on constantly in plants and animals
Most of the reactions happen inside mitochondria
Aerobic respiration equation
-- Correct Answer --Glucose + oxygen --> carbon dioxide + water
Anaerobic respiration - animals -- Correct Answer --Respiration without oxygen
Incomplete breakdown of glucose
Happens when your body can't supply enough oxygen to your muscles during vigorous exercise
Doesn't transfer as much energy as aerobic respiration - glucose isn't fully oxidised.
,Anaerobic respiration - plants & yeasts -- Correct Answer --In yeasts, it's called fermentation
Fermentation is used to make bread and alcoholic drinks
Anaerobic respiration equation - animals -- Correct Answer --Glucose --> lactic acid
Anaerobic respiration equation - plants and yeasts -- Correct Answer --Glucose --> ethanol +
carbon dioxide
Aspirin -- Correct Answer --Used as a painkiller & to lower fever
Developed from a chemical found in willow
Avoiding Contamination -- Correct Answer --1) The Petri dishes & culture medium must be
sterilised before use (heating to a high temperature), to kill any unwanted microorganisms
2) If an inoculating loop is used to transfer the bacteria to the culture medium, it should be
sterilised first by passing it through a hot flame
3) After transferring the bacteria, the lid of the Petri dish should be lightly taped on - to stop any
microorganisms from the air getting it
4) The Petri dish should be stored upside down - stops drops of condensation falling onto the
agar surface
B-lymphocytes - white blood cells -- Correct Answer --Recognise foreign antigens on cells and
produce antibodies to lock onto the antigens so that the cells can be located and destroyed
The antibodies are specific to that type of antigen - they form a lock-and-key connection.
Benedict's Test - testing for sugars -- Correct Answer --1) Prepare a food sample & transfer 5cm³
to a test tube
,2) Prepare a water bath so that it's set to 75°C
3) Add some Benedict's solution to the test tube (about 10 drops) using a pipette
4) Place the test tube in the water bath using a test tube holder & leave it there for 5 minutes.
Ensure the tube is pointing away from you
5) If the food sample contains a reducing sugar, the solution in the test tube will change from the
normal blue colour to green, yellow or brick-red - depending on how much sugar is in the food
Big Molecules -- Correct Answer --Starch
Proteins
Fats
Biuret Test - testing for proteins -- Correct Answer --1) Prepare a sample of your food & transfer
2cm³ of it to a test tube
2) Add 2cm³ of biuret solution to the sample & mix the contents of the tube by gently shaking it
3) If the food sample contains protein, the solution will change from blue to pink or purple
Calculation - Rate of Reaction -- Correct Answer --Rate = 1000/time
Chemical defences of plants -- Correct Answer --1) Antibacterial chemicals - these kill bacteria
and are found in mint plants and witch hazels
2) Poisons helped to deter herbivores from eating them e.g. tobacco plants, foxgloves and deadly
nightshade
Cilia as a defence -- Correct Answer --Hair-like structures which waft the mucus up to the back
of your throat where it can be swallowed (and used to trap pathogens)
, Common symptoms of plant diseases -- Correct Answer --1) Stunted growth
2) Abnormal growths e.g. lumps
3) Spots on the leaves
4) Malformed stems or leaves
5) Patches of decay (rot)
6) Discolouration
CONS of vaccinations -- Correct Answer --1) Sometimes they don't give you immunity
2) They can sometimes trigger bad reactions e.g. swelling, fevers, and seizures - bad reactions
are very rare
Digitalis -- Correct Answer --Used to treat heart conditions
Developed from a chemical found in foxgloves
Disadvantages of Stem Cells -- Correct Answer --1) Stem cells grown in the lab may become
contaminated with a virus - this will be passed onto the patient & make them sicker
2) Some people think that human embryos shouldn't be used for experiments - each one is a
potential human life
3) Scientists should focus more on finding & developing other sources of stem cells
Drinking as a risk factor -- Correct Answer --Drinking too much alcohol causes liver disease,
affects brain function and damages the nerve cells in the brain
Drug testing - Stage 1 -- Correct Answer --Drugs are tested on human cells and tissues
and Answers 2024/2025
Adaptations of Exchange Surfaces
-- Correct Answer –
a) large surface area - lots of substances can diffuse at once
b) Lots of blood vessels - to get stuff into and out of the blood quickly
c) thin membrane - short distance for substances to diffuse
d) Often ventilated - air moves in & out
Aerobic respiration
-- Correct Answer --Respiration using oxygen
Goes on constantly in plants and animals
Most of the reactions happen inside mitochondria
Aerobic respiration equation
-- Correct Answer --Glucose + oxygen --> carbon dioxide + water
Anaerobic respiration - animals -- Correct Answer --Respiration without oxygen
Incomplete breakdown of glucose
Happens when your body can't supply enough oxygen to your muscles during vigorous exercise
Doesn't transfer as much energy as aerobic respiration - glucose isn't fully oxidised.
,Anaerobic respiration - plants & yeasts -- Correct Answer --In yeasts, it's called fermentation
Fermentation is used to make bread and alcoholic drinks
Anaerobic respiration equation - animals -- Correct Answer --Glucose --> lactic acid
Anaerobic respiration equation - plants and yeasts -- Correct Answer --Glucose --> ethanol +
carbon dioxide
Aspirin -- Correct Answer --Used as a painkiller & to lower fever
Developed from a chemical found in willow
Avoiding Contamination -- Correct Answer --1) The Petri dishes & culture medium must be
sterilised before use (heating to a high temperature), to kill any unwanted microorganisms
2) If an inoculating loop is used to transfer the bacteria to the culture medium, it should be
sterilised first by passing it through a hot flame
3) After transferring the bacteria, the lid of the Petri dish should be lightly taped on - to stop any
microorganisms from the air getting it
4) The Petri dish should be stored upside down - stops drops of condensation falling onto the
agar surface
B-lymphocytes - white blood cells -- Correct Answer --Recognise foreign antigens on cells and
produce antibodies to lock onto the antigens so that the cells can be located and destroyed
The antibodies are specific to that type of antigen - they form a lock-and-key connection.
Benedict's Test - testing for sugars -- Correct Answer --1) Prepare a food sample & transfer 5cm³
to a test tube
,2) Prepare a water bath so that it's set to 75°C
3) Add some Benedict's solution to the test tube (about 10 drops) using a pipette
4) Place the test tube in the water bath using a test tube holder & leave it there for 5 minutes.
Ensure the tube is pointing away from you
5) If the food sample contains a reducing sugar, the solution in the test tube will change from the
normal blue colour to green, yellow or brick-red - depending on how much sugar is in the food
Big Molecules -- Correct Answer --Starch
Proteins
Fats
Biuret Test - testing for proteins -- Correct Answer --1) Prepare a sample of your food & transfer
2cm³ of it to a test tube
2) Add 2cm³ of biuret solution to the sample & mix the contents of the tube by gently shaking it
3) If the food sample contains protein, the solution will change from blue to pink or purple
Calculation - Rate of Reaction -- Correct Answer --Rate = 1000/time
Chemical defences of plants -- Correct Answer --1) Antibacterial chemicals - these kill bacteria
and are found in mint plants and witch hazels
2) Poisons helped to deter herbivores from eating them e.g. tobacco plants, foxgloves and deadly
nightshade
Cilia as a defence -- Correct Answer --Hair-like structures which waft the mucus up to the back
of your throat where it can be swallowed (and used to trap pathogens)
, Common symptoms of plant diseases -- Correct Answer --1) Stunted growth
2) Abnormal growths e.g. lumps
3) Spots on the leaves
4) Malformed stems or leaves
5) Patches of decay (rot)
6) Discolouration
CONS of vaccinations -- Correct Answer --1) Sometimes they don't give you immunity
2) They can sometimes trigger bad reactions e.g. swelling, fevers, and seizures - bad reactions
are very rare
Digitalis -- Correct Answer --Used to treat heart conditions
Developed from a chemical found in foxgloves
Disadvantages of Stem Cells -- Correct Answer --1) Stem cells grown in the lab may become
contaminated with a virus - this will be passed onto the patient & make them sicker
2) Some people think that human embryos shouldn't be used for experiments - each one is a
potential human life
3) Scientists should focus more on finding & developing other sources of stem cells
Drinking as a risk factor -- Correct Answer --Drinking too much alcohol causes liver disease,
affects brain function and damages the nerve cells in the brain
Drug testing - Stage 1 -- Correct Answer --Drugs are tested on human cells and tissues
