Chapter 16.3, Problem 1CS

Core Skill: Modeling The goal of this modeling challenge is to predict the outcome of meiosis if one pair of chromosomes does not separate properly during meiosis II.

Modeling Challenge: In Figure 16.13, the starting cell in meiosis I has 3 homologous pairs of chromosomes that differ in length: short, medium, and long. Let’s suppose that during meiosis I, the segregation of the long chromosomes into the two daughter cells occurs abnormally, and both of the long chromosomes go into the same daughter cell. Draw a model showing the chromosomal composition of the four daughter cells at the end of meiosis II. For each pair of homologs, draw one red and the other blue, as in the figure. You do not need to include crossovers in your model.

Figure 16.3 Checkpoints in the cell cycle. This is a general diagram of the eukaryotic cell cycle. Advancement through the cell cycle requires the formation of activated cyclin/cdk complexes. Cells make different types of cyclin proteins, which are typically degraded after the cell has advanced to the next phase. The formation of activated cyclin/cdk complexes is regulated by checkpoint proteins.