Review Questions
1. List the three foundational statements of the cell theory.
2. When you cut the tip of a finger, a scab forms and new skin appears underneath the scab. If you cut your finger deeply enough, however, it may take a long time to regain the feeling in the tip of your finger. Use your understanding of the cell cycle to explain these observations.
3. Do you expect the rate of cell division to be higher in an adult or a child? Explain your answer.
4. Describe the three stages of interphase, and explain their importance.
5. Using Figure 4.4, identify the phase of mitosis that each of the following events occur in.
a. migration of sister chromatids to the poles
b. condensation of chromatin into chromosomes
c. formation of a nuclear membrane
6. Sketch the four phases of mitosis. Include labels to explain what is happening in each phase.
7. Imagine you are a chromosome in a cell undergoing mitosis. Describe the key events that you experience.
8. State the important functions of mitosis and cytokinesis.
9. How do daughter cells compare genetically to the parent cell?
10. Scientists in a lab have isolated a substance that prevents cells from synthesizing spindle fibres. How would this substance affect cell division? Explain.
11. A scientist studying a group of somatic cells notices that when the cell cycle is complete, half of the daughter cells have no chromosomes and the other half have 92 chromosomes. In what phase of mitosis did an error most likely occur? Explain.
12. Using a diagram or flowchart, illustrate the relationships among nucleotide, DNA, gene, allele, chromatin, and chromosome.
13. Why is the word homologous used to describe chromosome pairs, rather than the word identical?
14. Sketch a pair of homologous chromosomes as they would appear during metaphase of mitosis. Label the following: sister chromatids, centromere, gene, and allele.
15. Draw and label a karyotype for an organism that has three pairs of homologous chromosomes.
16. Why are the X and Y chromosomes commonly referred to as the sex chromosomes?
17. The image below shows chromosomes in a human cell.
a. What is this representation called and how is it prepared?
b. Identify the sex of the individual.
c. Does this individual have the correct number of chromosomes?
18. How would a karyotype help doctors to diagnose a genetic disorder that results from the partial deletion of one end of a chromosome?
Section 4.2 Sexual Reproduction