DP Biology (first assessment 2025)

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Question 21M.2.SL.TZ1.a

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Date May 2021 Marks available [Maximum mark: 3] Reference code 21M.2.SL.TZ1.a
Level SL Paper 2 Time zone TZ1
Command term Describe Question number a Adapted from N/A
a.
[Maximum mark: 3]
21M.2.SL.TZ1.a

Describe the genetic and hormonal control of male sexual characteristics in a human.

[3]

Markscheme

a. male if (X and) Y chromosomes present ✔

b. gene on Y chromosome/SRY promotes development of testes (from embryonic gonads) ✔

c. testes secrete testosterone ✔

d. testosterone stimulates sperm production/spermatogenesis ✔

e. testosterone stimulates development (in fetus) of male genitals/primary sexual characteristics ✔

f. testosterone stimulates development of male secondary sexual characteristics
OR
testosterone causes changes to become adult male during puberty ✔

Allow first alternative for mpf if two secondary sexual characteristics are named instead of the general term ‘secondary sexual characteristics’.

Examiners report

There were some excellent answers that easily scored the three marks, but also many poorer ones, sometimes with no mention of genetic control or testosterone.

Syllabus sections