DP Biology (last assessment 2024)
Question 18M.2.HL.TZ2.d.ii
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.2.HL.TZ2.d.ii |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Suggest | Question number | d.ii | Adapted from | N/A |
d.ii.
[Maximum mark: 2]
18M.2.HL.TZ2.d.ii
Leaves were removed from Arabidopsis plants that had been grown in long day and short day conditions and the concentration of starch within them was measured. This was done both at the end of the day (D) and at the end of the night (N) in each of the four stages of development (S1, S2, S3, S4).
Suggest reasons for the difference in end of day starch concentrations in stage 2 (S2) for the plants grown in long days and short days.
[2]
Markscheme
a. leaves in plants grown in long day receive longer period of light / more leaf surface area so more photosynthesis occurs resulting in more starch. Accept vice versa.
b. plants in short days using starch to produce more leaves/for growth/S2 a period of rapid increase in number of leaves. Accept vice versa.
