DP Biology (first assessment 2025)

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Question 21M.2.HL.TZ1.1d

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Date May 2021 Marks available [Maximum mark: 1] Reference code 21M.2.HL.TZ1.1d
Level HL Paper 2 Time zone TZ1
Command term Suggest Question number d Adapted from N/A
d.
[Maximum mark: 1]
21M.2.HL.TZ1.1d
(d)

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

[1]

Markscheme

a. still some mitosis ✔

b. individual cells grow/elongate (expand by absorbing water) ✔

c. NVP is not 100 % effective / does not enter all of the cells / not all cells have come in contact with NVP ✔

d. roots have reached maximum saturation of NVP and are no longer functionally affected ✔

e. some cells are resistant to the drug ✔

Accept reasonable suggestions. 

Examiners report

Most candidates earned this mark; some gave imaginative answers.

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