A-Level Biology A (H420/01) - Mark Scheme
Section A (Multiple-Choice Questions)
For multiple-choice questions, correct answers are given below. Each correct answer is worth 1
mark.
1. B 2. B 3. A 4. A 5. D 6. A 7. D 8. B 9. B 10. A 11. D 12. C 13. B 14. B 15. C
Section B (Structured and Extended Response Questions)
Each question is marked with indicative marking points and levels of response for extended
answers.
Question 16
Bond in maltose (2 marks)
- Glycosidic bond between carbon-1 of one glucose and carbon-4 of another.
- Condensation reaction removes a molecule of water.
Question 17
Survival in a sealed container (3 marks)
- Photosynthesis produces oxygen needed for respiration.
- Respiration produces carbon dioxide needed for photosynthesis.
- Balanced recycling of gases supports long-term survival.
Question 18
Homeostasis of blood water content (6 marks)
- ADH release from pituitary gland.
- Binds to receptors on collecting duct cells.
- Aquaporins inserted into membrane, increasing water reabsorption.
- More water reabsorbed when dehydrated (high ADH), less when hydrated (low ADH).
- Negative feedback maintains water balance.
Study Tips for OCR A-Level Biology
1. Understand Mark Schemes: Learn what examiners look for.
2. Practice Application: Apply knowledge to unfamiliar contexts.
3. Use Scientific Terminology: Be precise with biological terms.
4. Time Management: Aim for 1 mark per minute.
Section A (Multiple-Choice Questions)
For multiple-choice questions, correct answers are given below. Each correct answer is worth 1
mark.
1. B 2. B 3. A 4. A 5. D 6. A 7. D 8. B 9. B 10. A 11. D 12. C 13. B 14. B 15. C
Section B (Structured and Extended Response Questions)
Each question is marked with indicative marking points and levels of response for extended
answers.
Question 16
Bond in maltose (2 marks)
- Glycosidic bond between carbon-1 of one glucose and carbon-4 of another.
- Condensation reaction removes a molecule of water.
Question 17
Survival in a sealed container (3 marks)
- Photosynthesis produces oxygen needed for respiration.
- Respiration produces carbon dioxide needed for photosynthesis.
- Balanced recycling of gases supports long-term survival.
Question 18
Homeostasis of blood water content (6 marks)
- ADH release from pituitary gland.
- Binds to receptors on collecting duct cells.
- Aquaporins inserted into membrane, increasing water reabsorption.
- More water reabsorbed when dehydrated (high ADH), less when hydrated (low ADH).
- Negative feedback maintains water balance.
Study Tips for OCR A-Level Biology
1. Understand Mark Schemes: Learn what examiners look for.
2. Practice Application: Apply knowledge to unfamiliar contexts.
3. Use Scientific Terminology: Be precise with biological terms.
4. Time Management: Aim for 1 mark per minute.
