B5 Growth and Developement PAGE 3

Fertilisation

• Nuclear of sperm and egg join up.
• The Zygote gets on set of chromosomes from each parent.

What's a DNA?

• A chromosone is a long molecule of DNA wound around a protein framework.
• A human DNA molecule is made up of about 30,000 genes.

A DNA is a double helix (two strands twisted togetherin a spiral)

• Bases connect…