# Explain how the structure of a sperm cell is adapted for its function in fertilisation.

> IB DP Biology Standard Level (2023 syllabus) — B2.3 Cell specialisation · Explain · 4 marks

## Mark scheme (4 marks)

1. The acrosome (at the tip of the head) contains hydrolytic enzymes that digest the zona pellucida / egg coat, allowing the sperm to penetrate the egg.
2. The nucleus (in the head) is haploid, carrying half the genetic information so that fertilisation restores the diploid number.
3. The midpiece is packed with mitochondria that produce ATP by aerobic respiration to power the movement of the flagellum.
4. The flagellum (tail) propels the sperm cell towards the egg by beating/rotating, enabling it to travel through the female reproductive tract.

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