Lesson 5 of 8

Fertilisation

Goal: Describe fertilisation and implantation.

Puzzles for this lesson

Fertilisation is the moment when the nucleus of a sperm cell joins with the nucleus of an egg cell.

Follow the egg and the sperm, one step at a time.

Fertilisation happens in an oviduct. Millions of sperm set off. Only one joins with the egg.
The fertilised egg has a new combination of DNA. Half of its genetic information comes from each parent.
Implantation comes next. The embryo settles into the lining of the uterus, where it grows.
Low fertility means that pregnancy is less likely. Causes include too few sperm, no egg being released, and blocked oviducts.

Your turn

This lesson’s activity starts here in a moment.

I can define fertilisation as two nuclei joining.I can say where it happens and where the embryo settles.

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Oviduct The tube from an ovary to the uterus, where fertilisation happens

Uterus The organ where a baby develops, also called the womb

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

Embryo The ball of cells that grows from a fertilised egg

Implantation The embryo settling into the lining of the uterus

For teachers: AQA 3.10.2 · Cambridge 9Bp.01