AQA A LEVEL BIOLOGY PAPER 2
7402-2 MARK SCHEME MS
COMPREHENSIVE STUDY GUIDE 2026
FULL QUESTIONS AND SOLUTIONS
GRADED A+
◍ 1. Order of animo acids in protein sequenced allowing mRNA to be
determined, therefore cDNA to be sequenced 2. Feed cDNA into computer
3. Check sequence passes international standard biosafety 4. Computer
designs series of small overlapping strands of single stranded DNA called
oligonucleotides which are assembled into desired gene 5. Oligonucleotides
joined together to make gene and gene replicated using PCR 6. PCR also
makes copied genes double stranded 7. Gene inserted into bacterial cell or
other organism (in vivo cloning)8. Genes in transformed organisms checked
using genetic sequencing. Those containing errors are rejected.
Answer: Outline the method used to manufacture genes using a gene
machine (8)
◍ 1. Altering the alleles of the sex cells so offspring has zero probability to
inherit the disorder2. Currently illegal in humans.
Answer: Describe the mechanism of germ line gene therapy (2)
(knowledge-based)
◍ 1. Found in the first few divisions of a fertilised egg2. Can differentiate into
any cell.
Answer: Totipotent Stem cells (2) [Where are they found?][Power]
(knowledge-based)
◍ Lens.
, Answer: Focus light onto the back of the eye
◍ Abiotic factors.
Answer: Non living e.g light, temp, water, wind and oxygen
◍ 1. Obtaining stem cells via embryos created from IVF results in the
destruction of an embryo that could have become a foetus2. Some people
think moment of fertilisation is first sign of life3. iPS cells could be used as
they have the same function4. Should embryonic stem cells be treated as
people or as commodity?.
Answer: Suggest four ethical issues surrounding embryonic stem cells (4)
(knowledge-based)
◍ Blood concentration.
Answer: If too concentrated:ADH secreted so more water is absorbed.If too
dilute:ADH no longer secreted and more urine is produced
◍ Sexual reproduction.
Answer: 1. Chromosomes are copied2. Cells divide to form 4 daughter
cells3. Chromosomes are single4. Cells are fertilised 5. The cell has
chromosome pairs6. Mitosis occurs to form an embryoIt provides variation
and therfore provides a survival advantage
◍ 1. Bone marrow 2. Can only differentiate into a single type of cell.
Answer: Unipotent Cells (2) [Where are they found?][Power]
(knowledge-based)
◍ 1. Organic N compounds decomposed to NH4+ by saprobionts..
Answer: Stage 2 of the nitrogen cycle: Ammonification (1)
(knowledge-based)
◍ Length of myosin.
Answer: Define A-band (1)
◍ Sterilisation.
Answer: +Very effective-hard to reverse
◍ 1. Amino acids are hydrolysed and the amino group is removed2. Carbon
, compound remaining enters krebs.
Answer: Describe how amino acids enter the krebs cycle (2).
◍ Genotype.
Answer: Tells us the alleles present in a person. Ee = heterozygous ee =
homozygous.
◍ I - (F+R).
Answer: Net production equation
◍ 1. Use tapes placed at right angles to produce a grid 2. Use a random
number table to generate pairs of numbers to be used as coordinates for
areas on the grid. 3. Sample in those areas using a quadrat 4. Use at least 30
quadrats so that sample is representative 5. Count all squares occupied by
each species being sampled (percentage cover) in total and divide by 30 to
get mean percentage cover..
Answer: Required Practical 12: Random Sampling mark scheme (use this
mark scheme for questions asking about same abiotic factors, like sand
dunes) (5) [Make your answer specific to the question to gain full marks]
◍ Thyroid.
Answer: Controls basil metabolic rate
◍ Homeostasis.
Answer: The regulation of the internal conditions of a cell or organism to
maintain optimum conditions for function in response to internal and
external changes
◍ 1. Slow twitch are reddish in colour due to myoglobin whereas fast twitch
are whiteish in colour as they do not have myoglobin2. Slow twitch are for
endurance whereas fast twitch are used for explosive power.3. Slow twitch
undergoes aerobic respiration whereas fast twitch undergoes anaerobic
respiration4. Slow twitch contract slowly whereas fast twitch contract
rapidly5. Fast twitch have a high storage of glycogen and phosphocreatine
whereas slow twitch has many mitochondria6. Slow twitch has a greater
ATP synthesis rate whereas fast twitch has a greater ATP hydrolysis rate.
, Answer: Contrast and compare slow twitch and fast twitch muscle fibres. (6)
(knowledge-based)
◍ 1. Adrenaline is released from the adrenal glands and binds to receptors on
the surface of target cells2. This stimulates adenylate cyclase to convert
ATP into cyclic adenosine monophosphate (cAMP). cAMP acts as a second
messenger.3. cAMP activates protein kinase which hydrolyses glycogen -->
glucose (glycogenolysis)4. Can also activate enzymes involved in
gluconeogenesis..
Answer: When mammals are in danger, a fight or flight response is
exhibited by the hormone adrenaline. Describe and explain the adrenaline
response to danger. (4) (Same mark scheme and pathway as glucagon, but
they are released from different areas) (knowledge-based)
◍ Hypothalamus.
Answer: Give the location of osmoreceptors in the body of a mammal (1).
◍ 1. Blood enters kidneys via renal artery at a high pressure 2. Renal Artery
divides into the afferent arteriolar and then the glomerulus 3. Water, ions
and glucose are forced out of the glomerulus down a pressure gradient
through small gaps in capillary endothelium, into the Bowmann's capsule. 4.
Pressure gradient is aided by the efferent arteriolar being narrower than
afferent 5. Proteins are left behind in blood as they are too large 6.
Glomerular filtrate is formed.
Answer: Describe the process of ultrafiltration (6) (knowledge-based)
◍ Cuttings.
Answer: 1. Remove a small growing part (meristem at shoot)2. Put it in
rooting powder 3. Replant it4. Grow the cloneBeen used for 100 years
◍ Automatic control system.
Answer: Nervous or endocrine system- receptor cells detect a stimulus- they
pass the information to the coordination centre- the coordination centre
processes the information-instructions are sent to the effector
◍ Variation.
7402-2 MARK SCHEME MS
COMPREHENSIVE STUDY GUIDE 2026
FULL QUESTIONS AND SOLUTIONS
GRADED A+
◍ 1. Order of animo acids in protein sequenced allowing mRNA to be
determined, therefore cDNA to be sequenced 2. Feed cDNA into computer
3. Check sequence passes international standard biosafety 4. Computer
designs series of small overlapping strands of single stranded DNA called
oligonucleotides which are assembled into desired gene 5. Oligonucleotides
joined together to make gene and gene replicated using PCR 6. PCR also
makes copied genes double stranded 7. Gene inserted into bacterial cell or
other organism (in vivo cloning)8. Genes in transformed organisms checked
using genetic sequencing. Those containing errors are rejected.
Answer: Outline the method used to manufacture genes using a gene
machine (8)
◍ 1. Altering the alleles of the sex cells so offspring has zero probability to
inherit the disorder2. Currently illegal in humans.
Answer: Describe the mechanism of germ line gene therapy (2)
(knowledge-based)
◍ 1. Found in the first few divisions of a fertilised egg2. Can differentiate into
any cell.
Answer: Totipotent Stem cells (2) [Where are they found?][Power]
(knowledge-based)
◍ Lens.
, Answer: Focus light onto the back of the eye
◍ Abiotic factors.
Answer: Non living e.g light, temp, water, wind and oxygen
◍ 1. Obtaining stem cells via embryos created from IVF results in the
destruction of an embryo that could have become a foetus2. Some people
think moment of fertilisation is first sign of life3. iPS cells could be used as
they have the same function4. Should embryonic stem cells be treated as
people or as commodity?.
Answer: Suggest four ethical issues surrounding embryonic stem cells (4)
(knowledge-based)
◍ Blood concentration.
Answer: If too concentrated:ADH secreted so more water is absorbed.If too
dilute:ADH no longer secreted and more urine is produced
◍ Sexual reproduction.
Answer: 1. Chromosomes are copied2. Cells divide to form 4 daughter
cells3. Chromosomes are single4. Cells are fertilised 5. The cell has
chromosome pairs6. Mitosis occurs to form an embryoIt provides variation
and therfore provides a survival advantage
◍ 1. Bone marrow 2. Can only differentiate into a single type of cell.
Answer: Unipotent Cells (2) [Where are they found?][Power]
(knowledge-based)
◍ 1. Organic N compounds decomposed to NH4+ by saprobionts..
Answer: Stage 2 of the nitrogen cycle: Ammonification (1)
(knowledge-based)
◍ Length of myosin.
Answer: Define A-band (1)
◍ Sterilisation.
Answer: +Very effective-hard to reverse
◍ 1. Amino acids are hydrolysed and the amino group is removed2. Carbon
, compound remaining enters krebs.
Answer: Describe how amino acids enter the krebs cycle (2).
◍ Genotype.
Answer: Tells us the alleles present in a person. Ee = heterozygous ee =
homozygous.
◍ I - (F+R).
Answer: Net production equation
◍ 1. Use tapes placed at right angles to produce a grid 2. Use a random
number table to generate pairs of numbers to be used as coordinates for
areas on the grid. 3. Sample in those areas using a quadrat 4. Use at least 30
quadrats so that sample is representative 5. Count all squares occupied by
each species being sampled (percentage cover) in total and divide by 30 to
get mean percentage cover..
Answer: Required Practical 12: Random Sampling mark scheme (use this
mark scheme for questions asking about same abiotic factors, like sand
dunes) (5) [Make your answer specific to the question to gain full marks]
◍ Thyroid.
Answer: Controls basil metabolic rate
◍ Homeostasis.
Answer: The regulation of the internal conditions of a cell or organism to
maintain optimum conditions for function in response to internal and
external changes
◍ 1. Slow twitch are reddish in colour due to myoglobin whereas fast twitch
are whiteish in colour as they do not have myoglobin2. Slow twitch are for
endurance whereas fast twitch are used for explosive power.3. Slow twitch
undergoes aerobic respiration whereas fast twitch undergoes anaerobic
respiration4. Slow twitch contract slowly whereas fast twitch contract
rapidly5. Fast twitch have a high storage of glycogen and phosphocreatine
whereas slow twitch has many mitochondria6. Slow twitch has a greater
ATP synthesis rate whereas fast twitch has a greater ATP hydrolysis rate.
, Answer: Contrast and compare slow twitch and fast twitch muscle fibres. (6)
(knowledge-based)
◍ 1. Adrenaline is released from the adrenal glands and binds to receptors on
the surface of target cells2. This stimulates adenylate cyclase to convert
ATP into cyclic adenosine monophosphate (cAMP). cAMP acts as a second
messenger.3. cAMP activates protein kinase which hydrolyses glycogen -->
glucose (glycogenolysis)4. Can also activate enzymes involved in
gluconeogenesis..
Answer: When mammals are in danger, a fight or flight response is
exhibited by the hormone adrenaline. Describe and explain the adrenaline
response to danger. (4) (Same mark scheme and pathway as glucagon, but
they are released from different areas) (knowledge-based)
◍ Hypothalamus.
Answer: Give the location of osmoreceptors in the body of a mammal (1).
◍ 1. Blood enters kidneys via renal artery at a high pressure 2. Renal Artery
divides into the afferent arteriolar and then the glomerulus 3. Water, ions
and glucose are forced out of the glomerulus down a pressure gradient
through small gaps in capillary endothelium, into the Bowmann's capsule. 4.
Pressure gradient is aided by the efferent arteriolar being narrower than
afferent 5. Proteins are left behind in blood as they are too large 6.
Glomerular filtrate is formed.
Answer: Describe the process of ultrafiltration (6) (knowledge-based)
◍ Cuttings.
Answer: 1. Remove a small growing part (meristem at shoot)2. Put it in
rooting powder 3. Replant it4. Grow the cloneBeen used for 100 years
◍ Automatic control system.
Answer: Nervous or endocrine system- receptor cells detect a stimulus- they
pass the information to the coordination centre- the coordination centre
processes the information-instructions are sent to the effector
◍ Variation.
