Genes, Chromosomes And DNA
In the majority of cells we have a nucleus, within this nucleus we have
chromosomes are contain our DNA In humans we have 23 pairs of
chromosomes, one chromosome from each parent. And these chromosomes
contain the genetic information on the DNA
The DNA double helix is coiled up to form the arms of the chromosome. A gene
is small part of a chromosome, and therefore a small amount of DNA.
There can be different versions of the same gene, these are called alleles.
For example for the eye colour gene you can have two different versions,
consisting of two different colours.