Unit 2 - Genetics

This GCSE Biology quiz is all about genetics, the study of variation and inheritance. Genetics can also mean the genetic properties, characteristics or features of an organism. The rules of genetics were first worked out by Gregor Mendel in 1866 from studies of pea plants. He discovered that genetic particles (heredity units), which we now call genes, determine the features of the offspring. Later, with the discovery of DNA, we began to understand genetics much better.

Different versions of the same gene found on a pair of chromosomes in the nucleus of a cell are called alleles. These can determine features such as eye colour. Mendel recognised that there were dominant and recessive forms of these alleles. He also realised that genes are passed on from both parents and that recombination of genes during fertilisation is a random event. This means that every person on the Earth (other than identical twins who came from the same egg cell) has a unique set of genes. This can be analysed to provide a genetic fingerprint which looks a bit like a bar code!