The relationship between chromosomes, genes and DNA is explained.

The genetics of gender are discussed. We see how sperm carrying X and Y chromosomes result in female and male offspring, respectively.

First broadcast:
21 November 2008

Use models to work with students on their understanding of DNA, genes and chromosomes. The class could take part in decoding activities, producing paper-chain proteins.
Ask students to explain how a discrete characteristic, such as gender or tongue-rolling ability relies on the combination of genes from parents. A person's sex is a particularly clear example and differences between XY and XX chromosome combinations can be related to inherited diseases that tend to affect one gender.