AP Biology Questions on Anaphase: Preparing for the Exam

📚 Quick Study Guide

• 🧬 Definition: Anaphase is the stage of mitosis and meiosis when chromosomes separate and move to opposite poles of the cell.
• 🏃‍♀️ Anaphase in Mitosis: Sister chromatids are pulled apart by shortening kinetochore microtubules. The cell elongates as non-kinetochore microtubules lengthen.
• 🌱 Anaphase I in Meiosis I: Homologous chromosomes separate, moving to opposite poles. Sister chromatids remain attached.
• ✂️ Anaphase II in Meiosis II: Similar to mitosis, sister chromatids separate and move to opposite poles.
• 🔬 Key Events:
  • 💨 Breakdown of cohesin proteins holding sister chromatids together.
  • 🎣 Movement of chromosomes along the spindle fibers.
  • 💪 Elongation of the cell.
• 🧪 Distinguishing Anaphase I from Anaphase II: Anaphase I involves separation of homologous chromosomes, while Anaphase II involves separation of sister chromatids.

Practice Quiz

1. Which of the following events characterizes anaphase?
   1. A. Chromosomes line up at the metaphase plate.
   2. B. Sister chromatids separate and move to opposite poles.
   3. C. The nuclear envelope reforms.
   4. D. Homologous chromosomes pair up.
2. What is the primary role of kinetochore microtubules during anaphase?
   1. A. To elongate the cell.
   2. B. To attach to the cell membrane.
   3. C. To shorten and pull sister chromatids apart.
   4. D. To form the nuclear envelope.
3. In anaphase I of meiosis, what separates?
   1. A. Sister chromatids.
   2. B. Homologous chromosomes.
   3. C. Non-sister chromatids.
   4. D. Centrosomes.
4. What happens to the cohesin proteins during anaphase?
   1. A. They bind the spindle fibers.
   2. B. They are broken down, allowing sister chromatids to separate.
   3. C. They help in the formation of the nuclear envelope.
   4. D. They replicate.
5. Which of the following is NOT a characteristic of anaphase?
   1. A. Movement of chromosomes.
   2. B. Elongation of the cell.
   3. C. Formation of the mitotic spindle.
   4. D. Separation of sister chromatids.
6. What is the difference between anaphase I and anaphase II?
   1. A. Anaphase I involves separation of sister chromatids, while anaphase II involves separation of homologous chromosomes.
   2. B. Anaphase I involves separation of homologous chromosomes, while anaphase II involves separation of sister chromatids.
   3. C. Anaphase I occurs in mitosis, while anaphase II occurs in meiosis.
   4. D. There is no difference between anaphase I and anaphase II.
7. If a cell has 20 chromosomes in G1 phase, how many chromatids are present during anaphase of mitosis?
   1. A. 10
   2. B. 20
   3. C. 40
   4. D. 80