BIO 101 / Meiosis stages Drawings

1. In the following diagram, draw what a cell with 1 chromosome would look like in the stages of meiosis. Prophase 1 is filled in for you and includes replicated homologous chromosomes; the black replicated chromosome is from the reproducing male’s mom and the grey replicated chromosome is from dad.

2. Maternal meiosis 2 nondisjunction results in 18-20% of trisomy 21 humans. In the following diagram, draw what could happen during meiosis 2 to cause Down syndrome. Prophase 1 is filled in with the replicated chromosomes for chromosome 21; don’t worry about drawing the other chromosomes.

3. People with Down syndrome can reproduce, and frequently their children do not have Down syndrome. Fill in the following diagram and explain why this could be. In the diagram, Prophase 1 shows the black replicated chromosomes 21 were inherited from the mother and the gray replicated chromosome 21 from the father; don’t worry about the other chromosomes.