Heterozygote and Homozygote

This sort of goes back to my post having to deal with Alleles. A homozygote is an individual with a dominant allele and a recessive allele for the same gene (humans have two alleles for each gene). A heterozygote means that a person either has two dominant alleles or two recessive alleles. An easy way (or at least I think easy) to understand this is to look at diseases: say you have a recessive disease, which means you will need to have both recessive alleles for the disease to affect you. An example of this is sickle cell anemia. If a person only has one copy of the recessive allele (a heterozygote), then they will not have the disease but will be considered a carrier. They can pass the disease on to a child if the other parent is a carrier as well. A person with both dominant alleles will neither have the disease nor be a carrier and cannot have a child with the disease.

Here's a good picture to explain it:

Source: http://genome.wellcome.ac.uk/doc_WTD020850.html

Now here's to hoping that I remember everything for my upcoming genetics exam as well as I did with this!