Lesson 1 of 8

Egg and sperm cells

Goal: Describe gametes and how they are adapted.

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Gametes are sex cells. The male gamete is the sperm cell. The female gamete is the egg cell.

A sperm cell: an oval head, a middle piece and a long thin tail
Sperm cell. About 0.05 mm long, and most of that is tail.
An egg cell: a large round cell with a nucleus in the middle and a jelly layer around the outside
Egg cell. About 0.1 mm across. The pictures are not to the same scale.
  • A sperm cell is built to swim. It has a tail and a streamlined head. Its many mitochondria release the energy it needs.
  • An egg cell is much bigger. Its cytoplasm holds a store of food for the first few days after fertilisation. It cannot move by itself.
  • Each gamete has a nucleus. The nucleus carries genetic information from one parent.

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Key words in this lesson

Gamete A sex cell: a sperm or an egg

Fertilisation The nucleus of a sperm joining with the nucleus of an egg

For teachers: AQA 3.10.2 · Cambridge 9Bp.01 in part