DP Biology (first assessment 2025)
Question 21M.2.HL.TZ2.b
| Date | May 2021 | Marks available | [Maximum mark: 4] | Reference code | 21M.2.HL.TZ2.b |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Describe | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 4]
21M.2.HL.TZ2.b
Describe how the structure of the chloroplast is adapted to its function in photosynthesis.
[4]
Markscheme
a. thylakoids have a small internal volume to maximize hydrogen gradient / quickly increase concentration gradient ✔
b. many grana / thylakoids give large surface area ✔
c. (grana) contain (photosynthetic) pigments/electron carriers/ATP synthase enzymes ✔
d. (photosynthetic) pigments/chlorophyll arranged into photosystems allowing maximum absorption of light energy ✔
e. stroma has suitable pH/ enzymes of Calvin/light independent cycle ✔
f. lamellae connect/separate grana maximizing photosynthetic efficiency ✔
Accept diagram showing the disposition in space.
Examiners report
Question 6 was a popular question.
Well answered.
