AQA A LEVEL BIOLOGY PAPER 2 – QUESTIONS AND
ANSWERS | VERIFIED AND WELL DETAILED
ANSWERS PLUS RATIONALES | GUARANTEED PASS |
LATEST EXAM UPDATE | EXAM PREP | STUDY GUIDE
| PRACTICE TEST| DOWNLOAD INSTANT PDF
1. A student investigates enzyme activity by measuring the rate of reaction at
different temperatures. The rate increases up to 40°C but then rapidly
decreases. What explains the decrease after 40°C?
A. The enzyme becomes more concentrated
B. The enzyme’s active site changes shape due to denaturation
C. More substrate molecules are produced
D. The reaction stops because no energy is available
Rationale: High temperatures break bonds maintaining enzyme structure,
causing denaturation and changing the active site so fewer enzyme-substrate
complexes form.
2. A scientist observes a cell under an electron microscope and identifies a
structure containing folded membranes and ribosomes. Which organelle is
being observed?
A. Golgi apparatus
B. Rough endoplasmic reticulum
C. Lysosome
D. Mitochondrion
Rationale: Rough endoplasmic reticulum contains ribosomes attached to its
surface and is involved in protein synthesis and transport.
3. A plant cell is placed into a solution with a lower water potential than the
cell contents. What will happen?
A. Water enters the cell by osmosis
B. The cell becomes turgid
,C. Water leaves the cell and the membrane pulls away from the cell wall
D. The cell gains solutes by active transport
Rationale: Water moves from higher water potential to lower water potential.
Loss of water causes plasmolysis in plant cells.
4. During aerobic respiration, where does the Krebs cycle occur?
A. Cytoplasm
B. Inner mitochondrial membrane
C. Mitochondrial matrix
D. Nucleus
Rationale: The Krebs cycle occurs in the mitochondrial matrix, producing
reduced NAD, reduced FAD, and ATP.
5. A mutation changes one nucleotide in a gene but does not change the amino
acid produced. What type of mutation has occurred?
A. Silent mutation
B. Frameshift mutation
C. Nonsense mutation
D. Deletion mutation
Rationale: A silent mutation changes a DNA base but does not alter the amino
acid because of the degeneracy of the genetic code.
6. Which statement correctly describes facilitated diffusion?
A. Movement against a concentration gradient using ATP
B. Movement through transport proteins down a concentration gradient
C. Movement of water only through membranes
D. Movement requiring vesicles
,Rationale: Facilitated diffusion is passive movement through channel or carrier
proteins without ATP use.
7. A student investigates photosynthesis by measuring oxygen production.
Which factor is being measured directly?
A. Respiration rate
B. Photosynthetic rate
C. Protein synthesis
D. Mineral uptake
Rationale: Oxygen is released during photosynthesis, so oxygen production can
indicate photosynthetic activity.
8. Which process produces genetically identical cells?
A. Meiosis
B. Fertilisation
C. Mitosis
D. Crossing over
Rationale: Mitosis produces two genetically identical daughter cells used for
growth and repair.
9. A student adds Benedict’s solution to a food sample and heats it. A brick-
red precipitate forms. What does this indicate?
A. Protein is present
B. Lipid is present
C. Reducing sugar is present
D. Starch is present
Rationale: Benedict’s test detects reducing sugars such as glucose, producing a
colour change and precipitate when heated.
, 10. Which molecule stores genetic information in living organisms?
A. ATP
B. DNA
C. Glycogen
D. Cellulose
Rationale: DNA stores hereditary information in the sequence of nucleotide
bases.
11. During DNA replication, which enzyme joins nucleotides together?
A. DNA polymerase
B. Helicase
C. Ligase only
D. Amylase
Rationale: DNA polymerase adds complementary nucleotides to form new DNA
strands.
12. A gene is described as a section of DNA that codes for:
A. A lipid molecule
B. A carbohydrate molecule
C. A polypeptide or functional RNA
D. A cell membrane
Rationale: Genes contain the information required to produce proteins or
functional RNA molecules.
13. Which structure controls movement of substances into and out of a cell?
A. Cell wall
B. Plasma membrane
ANSWERS | VERIFIED AND WELL DETAILED
ANSWERS PLUS RATIONALES | GUARANTEED PASS |
LATEST EXAM UPDATE | EXAM PREP | STUDY GUIDE
| PRACTICE TEST| DOWNLOAD INSTANT PDF
1. A student investigates enzyme activity by measuring the rate of reaction at
different temperatures. The rate increases up to 40°C but then rapidly
decreases. What explains the decrease after 40°C?
A. The enzyme becomes more concentrated
B. The enzyme’s active site changes shape due to denaturation
C. More substrate molecules are produced
D. The reaction stops because no energy is available
Rationale: High temperatures break bonds maintaining enzyme structure,
causing denaturation and changing the active site so fewer enzyme-substrate
complexes form.
2. A scientist observes a cell under an electron microscope and identifies a
structure containing folded membranes and ribosomes. Which organelle is
being observed?
A. Golgi apparatus
B. Rough endoplasmic reticulum
C. Lysosome
D. Mitochondrion
Rationale: Rough endoplasmic reticulum contains ribosomes attached to its
surface and is involved in protein synthesis and transport.
3. A plant cell is placed into a solution with a lower water potential than the
cell contents. What will happen?
A. Water enters the cell by osmosis
B. The cell becomes turgid
,C. Water leaves the cell and the membrane pulls away from the cell wall
D. The cell gains solutes by active transport
Rationale: Water moves from higher water potential to lower water potential.
Loss of water causes plasmolysis in plant cells.
4. During aerobic respiration, where does the Krebs cycle occur?
A. Cytoplasm
B. Inner mitochondrial membrane
C. Mitochondrial matrix
D. Nucleus
Rationale: The Krebs cycle occurs in the mitochondrial matrix, producing
reduced NAD, reduced FAD, and ATP.
5. A mutation changes one nucleotide in a gene but does not change the amino
acid produced. What type of mutation has occurred?
A. Silent mutation
B. Frameshift mutation
C. Nonsense mutation
D. Deletion mutation
Rationale: A silent mutation changes a DNA base but does not alter the amino
acid because of the degeneracy of the genetic code.
6. Which statement correctly describes facilitated diffusion?
A. Movement against a concentration gradient using ATP
B. Movement through transport proteins down a concentration gradient
C. Movement of water only through membranes
D. Movement requiring vesicles
,Rationale: Facilitated diffusion is passive movement through channel or carrier
proteins without ATP use.
7. A student investigates photosynthesis by measuring oxygen production.
Which factor is being measured directly?
A. Respiration rate
B. Photosynthetic rate
C. Protein synthesis
D. Mineral uptake
Rationale: Oxygen is released during photosynthesis, so oxygen production can
indicate photosynthetic activity.
8. Which process produces genetically identical cells?
A. Meiosis
B. Fertilisation
C. Mitosis
D. Crossing over
Rationale: Mitosis produces two genetically identical daughter cells used for
growth and repair.
9. A student adds Benedict’s solution to a food sample and heats it. A brick-
red precipitate forms. What does this indicate?
A. Protein is present
B. Lipid is present
C. Reducing sugar is present
D. Starch is present
Rationale: Benedict’s test detects reducing sugars such as glucose, producing a
colour change and precipitate when heated.
, 10. Which molecule stores genetic information in living organisms?
A. ATP
B. DNA
C. Glycogen
D. Cellulose
Rationale: DNA stores hereditary information in the sequence of nucleotide
bases.
11. During DNA replication, which enzyme joins nucleotides together?
A. DNA polymerase
B. Helicase
C. Ligase only
D. Amylase
Rationale: DNA polymerase adds complementary nucleotides to form new DNA
strands.
12. A gene is described as a section of DNA that codes for:
A. A lipid molecule
B. A carbohydrate molecule
C. A polypeptide or functional RNA
D. A cell membrane
Rationale: Genes contain the information required to produce proteins or
functional RNA molecules.
13. Which structure controls movement of substances into and out of a cell?
A. Cell wall
B. Plasma membrane
