AP Biology Unit 4 Homework: Cell Division and CancerTextbook Chapters: 12, 13 Test Date: ______

Lesson 1: Cellular DNA and the Cell Cycle

Begin by opening a browser and navigating to

Click on “Chromosomes and Inheritance”

1. Take the tour titled “What is a Chromosome?” Draw a picture that demonstrates how DNA is coiled into chromosomes:

Once you have your drawing, label the following: Chromatin, Histones, Chromatids, Chromosome, kinetochore

2. Using the information at and your power point to help you, answer the following:

a. Describe how DNA is coiled and eventually supercoiled to condense it into chromosomes.

b. What is the kinetochore? What’s it used for?

3. Next, go to and in the box on the upper right, click on “Learn about the Cell Cycle.” As you watch the animation, fill out the chart below:

Part of the Cell Cycle / What’s happening? / Associated checkpoints? What are they? What’s Happening

You may also find it useful to download and print the Cell Cycle Study Aid found under the animation. It is a visual way to represent the information in the chart, if you’d prefer. Either is acceptable.

4. People often use the term “Mitosis” and “The Cell Cycle” interchangeably. Is this correct? Explain your answer.

5. Next, go to and work through the animation as you answer the following:

a. What do cdc and rad mutants tell us about controlling the cell cycle?

b. Define apoptosis. What’s responsible for the pre-programmed cell death that all cells have?

c. What is p53 and what does it have to do with regulating the cell cycle?

d. What does cancer have to do with the cell cycle?

6. Go back to and click on “Are Telomeres the Key to Aging and Cancer?” (You may also find the video at to be helpful)

a. Define Telomere. Why are they necessary and how are they related to cell division?

b. What do telomeres have to do with cancer and aging?

7. Using your power point to help you, describe the various internal and external cues, besides the ones we’ve discussed so far, which regulate cell growth and division.

8. In the space below, write 3 questions about chromosomes and the cell cycle. If you don’t have any questions, then write 3 questions to predict how this material will appear on your test.

Lesson 2: Mitosis

1. Go to and use the animation and your textbook to fill out the chart below:

Stage of Mitosis / Description of what’s happening / Picture of what’s happening

(You may also find the mitosis phases and structures diagrams at cellsalive to be helpful for studying and they’re free)

Watch the video at to help you answer the following questions:

2. What is actually split during Mitosis?

3. What is a motor protein? How do they ensure that chromosomes line up in the middle of the cell?

4. What usually occurs simultaneously with telophase but is not necessarily part of mitosis?

Give an example of a human body cell that completes mitosis but not this step. Describe the resultant cells.

5. Using your book to help you, describe how plant cell mitosis is different from animal cell mitosis.

6. In the space below, write 3 questions about mitosis. If you don’t have any questions, then write 3 questions to predict how this material will appear on your test.

Lesson 3: Genes and Cancer

In the first lesson of this unit, you began to look at the cell cycle as it relates to aging and cancer. You had a chance to see how proteins and the genes that control their production can cause cancerous cells to form from normal cells. We’re now going to take a closer look at this process using the animations at this website:

1. Animation 1 Questions

a. Thinking back to Unit 3 and what you’ve learned in this unit so far, by what mechanisms do you think that cancers can form large masses of unregulated cells?

b. What’s the name of the process described at the end where cancers enter the blood stream and spread?

2. Animation 2 Questions: List the chemicals that you know to be a part of the cell cycle clock.

3. Animation 3 Questions:

a. Define in your own words “Protooncogene.”

b. Define in your own words “Tumor Supressor Genes.”

4. Animation 4 Questions:

a. Define in your own words “Mutagen.”

b. What does information about mutagens suggest about the connection between genes and cancer?

5. Animation 5 Questions:

a. How does a protooncogene become an oncogene?

b. How can mutations negatively impact tumor supressor genes?

6. Based on what you’ve learned, describe why cancers are more common as people age.

7. Describe the mechanism by which you suspect genes that promote cell division have the greatest potential to become cancerous.

8. Go back to and as you watch the animation again, list the checkpoints/proteins that you think are produed by protooncogenes and the ones that you think are produced by tumor supressor genes.

a. Protooncogenes-

b. Tumor Supressor Genes-

9. In the space below, write 3 questions about mitosis. If you don’t have any questions, then write 3 questions to predict how this material will appear on your test.

Lesson 4: Meiosis and Karyotyping

1. Using your book or your own internet research, draw a picture of a replicated chromosome and an unreplicated chromosome in the space below. Which would you describe as x-shaped and which would you describe as l-shaped?

2. Using the animation at fill in the chart below:

Phase of Meiosis / What’s Happening? / Chromosome Number (n or 2n) / Chromosome shape

(Again, here you may find the meiosis study aid to be helpful for you to print off and fill in as you prepare for your test)

3. What is the purpose of meiosis?

4. Watch the video at and answer the following:

a. How are mitosis and meiosis different?

b. Define Homologous chromosome pair.

c. Distinguish between diploid and haploid.

d. Describe the two important new steps that occur in Prophase I.

e. What does Meiosis and its events have to do with natural selection?

f. Why aren’t all of the cells that result from meiosis identical?

g. How is egg-making different from sperm-making?

Make sure that as you watch, you go back over the chart above and fill in any missing information.

5. Scientists can determine which chromosomes are homologous by reading the chromosomes. Go to and describe how scientists do this.

6. You might at this point be asking, “Why read a chromosome anyway?” Go to and describe how chromosomes are read to create karyotypes. What are karyotypes useful for?

7. Distinguish between autosomes and sex chromosomes. How many of each can be found in human cells?

8. Mistakes in meiosis are detectable in karyotypes. Describe, using the information on this site, what mistakes can occur and how they appear on a karyotype.

a. Trisomies and monosomies (aneuploidy)-

b. Deletions-

c. Translocations-

How are translocations different from crossing over in Prophase I?

9. When you’ve finished, try making a karyotype at

a. Is the karyotype that you made for a male or female? How do you know?

b. Did you find any chromosomal mutations on your karyotype?

c. What difficulties did you encounter trying to match up the homologous chromosomes?

10. In the space below, write 3 questions about meiosis and karyotyping. If you don’t have any questions, then write 3 questions to predict how this material will appear on your test.