Directions for Storyboard • In block three of the storyboard, draw a circle to represent the cell membrane. • Through the center of the circle, glue a pipecleaner – this represents the spindle of the cell. • Take pairs of chromosomes and line them up across the spindle and glue them in. The centromeres (or twisty-ties) should be on the spindle (the pipe cleaners). • At the left and right borders of the circle, glue a button. These represent the centrioles, or poles of the cell. Anaphase I 3) Anaphase I: a) One chromosome from each homologous pair of chromosomes move to opposite poles of the cell. Anaphase I Directions for Storyboard • Separate the homologous pairs of chromosomes and have them “pulled” towards opposite centrioles (poles) of the cell. • Glue into your storyboard in box #4 and label it, “Anaphase I.” Telophase I • Telophase I varies from species to species. Sometimes Telophase I is skipped and meiosis starts its second division immediately. In general, however, two nuclear envelopes begin to surround the separate chromosomes and cytokinesis (splitting of the cytoplasm into two separate entities) will sometimes occur. Then a phase called interkinesis will follow, which essentially is a resting period from Telophase I to Prophase II. This differs from mitosis because DNA replication does not occur. Telophase I in action! Directions for Storyboard • Draw one circle in box 5 of your storyboard. Faintly draw a dotted line on the cell in the middle (this is where the cell is dividing). There should be one button in each of the cells. • Take your yarn, jumble it up next the buttons or centrioles of your cell. You should have masses of chromosomes by each of the “poles.” • Cytokinesis usually follows, where the cytoplasm of the cell is is completely separated. From here, you should have two cells in your storyboard! Meiosis II In the second phase of Meiosis, a reduction division takes place. See if you can determine why this is a reduction! What stage (Meiosis I or Meiosis II) is most similar to Mitosis? There are four steps to Meiosis II: 1. Prophase II 2. Metaphase II 3. Anaphase II 4. Telophase II Prophase II • During Prophase II, each dyad (1/2 a tetrad) is composed of a pair of sister chromatids and they are connected by a centromere. The centrosomes (replicated during Telophase I) which produce the spindle fibers also start to move toward the poles of the cell. The graphical animation shows that only one dyad will be focused on. Prophase II Directions for the Storyboard • Draw two cells in box 6 of your storyboard. Each cell should have one button and chromosomes. • Replicate the poles by adding an extra button to either side of your two cells. • Between your two poles, form another spindle by gluing in another pipe cleaner. Each cell should have two poles (buttons) also called centrioles, and one spindle.