AQA Biology (UK A-Level) Paper 1 AS Exam Questions ( 100
Questions)
1. What are the monomers that make up proteins?
Answer: Amino acids.
2. Describe the role of hydrogen bonds in the structure of proteins.
Answer: Hydrogen bonds help stabilize the secondary and tertiary structures of
proteins by forming between polar groups within the polypeptide chain.
3. What type of reaction joins two monosaccharides?
Answer: A condensation reaction.
4. Give two examples of disaccharides and the monosaccharides they are
made from.
Answer:
Maltose: glucose + glucose
Sucrose: glucose + fructose
5. What is the main storage polysaccharide in animals?
Answer: Glycogen.
6. What feature of cellulose makes it suitable for its function in plant cell
walls?
Answer: It has straight, unbranched chains of β-glucose that form strong fibers due
to hydrogen bonding, giving structural support.
,7. Describe the structure of a triglyceride.
Answer: One glycerol molecule joined to three fatty acid chains via ester bonds.
8. Explain how the structure of phospholipids allows them to form bilayers.
Answer: They have hydrophilic heads and hydrophobic tails, allowing them to
arrange into bilayers with heads facing water and tails inward.
9. What test is used to detect the presence of a reducing sugar?
Answer: Benedict’s test.
10. How would you test for proteins in a food sample?
Answer: Use the Biuret test — a purple color indicates the presence of proteins.
11. Describe the induced fit model of enzyme action.
Answer: The enzyme's active site changes shape slightly to fit the substrate more
closely, enhancing the enzyme-substrate interaction.
12. How does temperature affect enzyme activity?
Answer: Temperature increases kinetic energy up to the optimum, increasing
collisions. Beyond the optimum, enzymes denature.
13. What is meant by the term ‘denaturation’?
Answer: A structural change in a protein (such as an enzyme) that results in loss of
function, often caused by heat or pH.
14. What effect does competitive inhibition have on enzyme activity?
Answer: It decreases activity by occupying the active site, preventing substrate
binding.
, 15. What is the function of the nucleus in a eukaryotic cell?
Answer: It stores DNA and controls cellular activities such as protein synthesis.
16. Name two organelles that have a double membrane.
Answer: Mitochondria and nucleus.
17. What is the function of lysosomes?
Answer: They contain digestive enzymes to break down waste materials and
cellular debris.
18. What is the difference between prokaryotic and eukaryotic cells?
Answer: Prokaryotes lack membrane-bound organelles and a true nucleus;
eukaryotes have both.
19. Name two structures found in plant cells but not in animal cells.
Answer: Cell wall and chloroplasts.
20. What is the magnification formula used in microscopy?
Answer: Magnification = Image size / Actual size
21. What is the function of the rough endoplasmic reticulum?
Answer: It processes and transports proteins synthesized by ribosomes attached to
it.
22. Describe the role of the Golgi apparatus.
Answer: It modifies, packages, and transports proteins and lipids.
Questions)
1. What are the monomers that make up proteins?
Answer: Amino acids.
2. Describe the role of hydrogen bonds in the structure of proteins.
Answer: Hydrogen bonds help stabilize the secondary and tertiary structures of
proteins by forming between polar groups within the polypeptide chain.
3. What type of reaction joins two monosaccharides?
Answer: A condensation reaction.
4. Give two examples of disaccharides and the monosaccharides they are
made from.
Answer:
Maltose: glucose + glucose
Sucrose: glucose + fructose
5. What is the main storage polysaccharide in animals?
Answer: Glycogen.
6. What feature of cellulose makes it suitable for its function in plant cell
walls?
Answer: It has straight, unbranched chains of β-glucose that form strong fibers due
to hydrogen bonding, giving structural support.
,7. Describe the structure of a triglyceride.
Answer: One glycerol molecule joined to three fatty acid chains via ester bonds.
8. Explain how the structure of phospholipids allows them to form bilayers.
Answer: They have hydrophilic heads and hydrophobic tails, allowing them to
arrange into bilayers with heads facing water and tails inward.
9. What test is used to detect the presence of a reducing sugar?
Answer: Benedict’s test.
10. How would you test for proteins in a food sample?
Answer: Use the Biuret test — a purple color indicates the presence of proteins.
11. Describe the induced fit model of enzyme action.
Answer: The enzyme's active site changes shape slightly to fit the substrate more
closely, enhancing the enzyme-substrate interaction.
12. How does temperature affect enzyme activity?
Answer: Temperature increases kinetic energy up to the optimum, increasing
collisions. Beyond the optimum, enzymes denature.
13. What is meant by the term ‘denaturation’?
Answer: A structural change in a protein (such as an enzyme) that results in loss of
function, often caused by heat or pH.
14. What effect does competitive inhibition have on enzyme activity?
Answer: It decreases activity by occupying the active site, preventing substrate
binding.
, 15. What is the function of the nucleus in a eukaryotic cell?
Answer: It stores DNA and controls cellular activities such as protein synthesis.
16. Name two organelles that have a double membrane.
Answer: Mitochondria and nucleus.
17. What is the function of lysosomes?
Answer: They contain digestive enzymes to break down waste materials and
cellular debris.
18. What is the difference between prokaryotic and eukaryotic cells?
Answer: Prokaryotes lack membrane-bound organelles and a true nucleus;
eukaryotes have both.
19. Name two structures found in plant cells but not in animal cells.
Answer: Cell wall and chloroplasts.
20. What is the magnification formula used in microscopy?
Answer: Magnification = Image size / Actual size
21. What is the function of the rough endoplasmic reticulum?
Answer: It processes and transports proteins synthesized by ribosomes attached to
it.
22. Describe the role of the Golgi apparatus.
Answer: It modifies, packages, and transports proteins and lipids.
