Biology Block_____ Name____________________________________
Dr. Wexler
Classwork: Cell Reproduction Higher Thinking Questions
Date:_______

1. Cell Cycle

   
   
   

1. A scientist is growing mouse skin cells in a petri dish. She then removes their nutrients, causing them to enter what cell cycle stage?

   A. G0 B. G1 C. S phase D. G2 E. Mitosis F. Cytokinesis

2. After starving the cells for 24 hours, she adds a hormone to stimulate growth. She measures DNA synthesis at various times after after adding the hormone. She discovers that DNA synthesis starts at 45 minutes, peaks at 60 minutes, and is compete by 75 minutes. Draw a graph illustrating these results. For your labels, use % maximal DNA synthesis on the Y axis and time on the X axis.

3. Cyclins are proteins that regulate the progress of the cell cycle. Their concentrations have to increase before the cells can exit G0 and progress to G1. What do you predict happens to the concentration of cyclins in the cell after M phase is compete?

2. Mitosis

   

4. Explain why eukaryotes, unlike prokarytoes, divide by mitosis instead of binary fission:

5. Explain how the mitotic spindle cause sister chromatids to separate and be drawn to opposite poles during anaphase:

6. What would be the consequence for the daughter cells if the centromere for one of the pairs of sister chromatids failed to split during anaphase?

A. daughter cell 1

B. daughter cell 2

7. Under what environmental circumstance would it be advantageous for cells to reproduce asexually?

8. Under what environmental circumstance would it be advantageous for cells to reproduce sexually (by mixing chromosomes from two different individuals)?