This is a really good picture that describes how gametes are produced. First the cell must go through mitosis, which creates sister chromatids. It then enters meiosis I, where they separate into different cells, very similar to how mitosis works. Meiosis II then starts, and separates the sister chromatids once again. The difference between mitosis and meiosis is that the cellular yield is four haploid (containing one set of chromosomes) cells instead of two diploid (containing two sets of chromosomes) cells.
Answer to yesterdays question: Frederick Griffith died from a bomb dropping down in his laboratory (located in the back of his house if I remember correctly). The S strain of the bacteria Griffith used was deadly because it secreted a capsule that stopped the body's defense mechanisms, while the R strain did not. This meant that the body could easily fight the R strain but the S strain was deadly with no antibiotics.
I must apologize for the lack of commenting I've been doing. This is an extremely stressful weekend, but I WILL catch up either Tuesday evening or Wednesday morning! My genetics test is this coming Tuesday and I feel so unprepared.