AQA A LEVEL BIOLOGY PAPER 1 2026 FINAL
REVIEW QUESTIONS ANSWERS BUNDLED
PRACTICE COLLECTION
◉ what are the functions of collagen?
Answer: 1. Form the structure of bones
2. Makes up cartilage and connective tissue
3. Prevents blood that is being pumped at high pressure from
bursting the walls of arteries
4. Is the main component of tendons, which connect skeletal muscles
to bones
◉ what type of bond forms between the phosphate group and
deoxyribose sugar in DNA?
Answer: phosphodiester bond
◉ why is DNA stable?
Answer: 1. the phosphodiester backbone protects the more
chemically reactive organic bases inside the double helix
2. many hydrogen bonds link the base pairs together, so it adds
strength overall.
,◉ how is DNA adapted to carrying out its function?
Answer: 1. it is very stable, thus rarely mutates
2. the H bonds can easily be separated during DNA replication and
protein synthesis
3. extremely large, thus carries a lot of genetic information
4. base pairing allows DNA to replicate and transfer info as mRNA.
◉ describe semi conservative replication
Answer: - DNA helicase unwinds separates the two strands of DNA
into single strands by breaking the H bonds between the bases
- this therefore forms 2 base templates (the bases on each strand are
exposed)
- free complimentary nucleotides align with the bases according to
complimentary base pairing
- they are joined via condensation reaction with DNA polymerase
- the new DNA molecule is formed
◉ what is meant by resolution
Answer: the minimum distance apart that two objects can be in
order for them to appear as separate items.
◉ before cell fractionation, why is the tissue placed in a cold,
isotonic buffer?
, Answer: cold: reduce enzyme activity that may break down the
organelles
isotonic: same water potential as tissue, this prevents organelles
shrinking/bursting due to osmotic loss/gain of water
buffered: so the pH doesn't fluctuate, so that nothing alters the
organelle structures or affects enzyme functioning
◉ what are the advantages of an electron microscope?
Answer: electron beam has a short wavelength and the microscope
can therefore has high resolution.
the negatively charged beam can be focused using electromagnets.
◉ what are the limitations of using a transmission electron
microscope?
Answer: the whole system must be in vacuum, so living specimens
cant be studied.
complex staining process
the image may contain artefacts
◉ what is the function of SER?
Answer: synthesises, stores and transports lipids and carbohydrates
◉ what is the function of RER?
REVIEW QUESTIONS ANSWERS BUNDLED
PRACTICE COLLECTION
◉ what are the functions of collagen?
Answer: 1. Form the structure of bones
2. Makes up cartilage and connective tissue
3. Prevents blood that is being pumped at high pressure from
bursting the walls of arteries
4. Is the main component of tendons, which connect skeletal muscles
to bones
◉ what type of bond forms between the phosphate group and
deoxyribose sugar in DNA?
Answer: phosphodiester bond
◉ why is DNA stable?
Answer: 1. the phosphodiester backbone protects the more
chemically reactive organic bases inside the double helix
2. many hydrogen bonds link the base pairs together, so it adds
strength overall.
,◉ how is DNA adapted to carrying out its function?
Answer: 1. it is very stable, thus rarely mutates
2. the H bonds can easily be separated during DNA replication and
protein synthesis
3. extremely large, thus carries a lot of genetic information
4. base pairing allows DNA to replicate and transfer info as mRNA.
◉ describe semi conservative replication
Answer: - DNA helicase unwinds separates the two strands of DNA
into single strands by breaking the H bonds between the bases
- this therefore forms 2 base templates (the bases on each strand are
exposed)
- free complimentary nucleotides align with the bases according to
complimentary base pairing
- they are joined via condensation reaction with DNA polymerase
- the new DNA molecule is formed
◉ what is meant by resolution
Answer: the minimum distance apart that two objects can be in
order for them to appear as separate items.
◉ before cell fractionation, why is the tissue placed in a cold,
isotonic buffer?
, Answer: cold: reduce enzyme activity that may break down the
organelles
isotonic: same water potential as tissue, this prevents organelles
shrinking/bursting due to osmotic loss/gain of water
buffered: so the pH doesn't fluctuate, so that nothing alters the
organelle structures or affects enzyme functioning
◉ what are the advantages of an electron microscope?
Answer: electron beam has a short wavelength and the microscope
can therefore has high resolution.
the negatively charged beam can be focused using electromagnets.
◉ what are the limitations of using a transmission electron
microscope?
Answer: the whole system must be in vacuum, so living specimens
cant be studied.
complex staining process
the image may contain artefacts
◉ what is the function of SER?
Answer: synthesises, stores and transports lipids and carbohydrates
◉ what is the function of RER?
