CHAPTER 9 Test Your Knowledge

Driving Question 1

By answering the questions below and studying Infographics 9.1 and 9.2 and Up Close: Cell Cycle and Mitosis, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

Following mitosis and cytokinesis, daughter cells are

a. genetically unique.

b. genetically identical to each other.

c. genetically identical to the parent cell.

d. contain half of the parent cell’s chromosomes.

e. b and c

In the cell cycle, DNA is replicated during

a. mitosis.

b. G₁.

c. S.

d. G₂.

e. cytokinesis.

What process is critical for embryonic development, wound healing, and replacement of blood cells? (Hint: All these processes require new cells.)

During which stage of the cell cycle do sister chromatids separate from each other?

During which stage of the cell cycle are sister chromatids initially produced?

USE IT

If a cell fails to replicate its DNA completely, what will happen?

a. It will progress through G₂ and mitosis.

b. It will die by apoptosis.

c. It will pause to allow DNA replication to complete.

d. It will stop in S phase and never progress further through the cell cycle.

e. It will stay in interphase indefinitely.

Many drugs interfere with cell division. Why shouldn’t pregnant women take these drugs?

What would be the result if a cell completed interphase and mitosis but failed to complete cytokinesis–how many cells would there be at that point, and how many chromosomes relative to the parent cell would those cells have?

Driving Question 2

By answering the questions below and studying Infographics 9.2, 9.3, 9.4, and 9.5 and Up Close: Cell Cycle and Mitosis, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

A normal cell that sustains irreparable DNA damage will most likely

a. divide out of control.

b. die by apoptosis.

c. arrest in G₂.

d. immediately go back to S phase.

e. stop in S phase and never progress through the cell cycle.

Which checkpoint prevents a normal cell from completing its cell cycle if it has not accurately replicated its DNA?

a. interphase (G₁–S)

b. interphase (G₂–M)

c. mitotic (M)

c. a and b

e. all of the above

USE IT

After a bad sunburn, skin usually peels. What process best describes what has happened to the burned skin cells?

a. skin cancer

b. metastasis

c. apoptosis

d. checkpoint failure

e. cytokinesis

Cancerous cells may not peel after a bad sunburn. What process has failed in this case?

a. DNA replication

b. signaling to divide

c. cytokinesis

d. checkpoints

e. mitosis

Complete the table below by placing a checkmark to indicate which cells will divide in which conditions. Growth factors (GFs) are molecules that signal normal cells to divide.

Driving Question 3

By answering the questions below and studying Infographics 9.6 and 9.7, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

A patient has metastatic melanoma–skin cancer that has spread throughout the body. Is surgery a viable option for this patient? Why or why not?

Which of the following properties should a promising new ovarian cancer drug have?

a. blocks mitosis in noncancerous cells

b. blocks mitosis in cancerous cells

c. prevents entry into S phase in normal cells

d. enhances the activity of cell cycle checkpoints in noncancerous cells

e. a and b

Explain why chemotherapy can cause nausea, diarrhea, and hair loss.

USE IT

Liver cells and neurons rarely, if ever, divide in normal circumstances. The cells lining the digestive tract are replaced by cell division on a regular basis. Explain why chemotherapy frequently causes digestive symptoms but less frequently causes cognitive symptoms.

Driving Question 4

By studying Infographics 9.4, 9.5, and 9.6 and answering the questions below, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

In the production of taxol:

a. What plant was at risk from early demand?

b. What animal was consequently put at risk?

If a medically valuable drug is isolated from a rare plant, which of the following steps can be taken to ensure that the drug is made available to patients in need and that the plant is protected from overuse?

a. Try to cultivate the plant on a farm to ensure that there is sufficient supply independent of the plant in its native setting.

b. Try to find a related (and less rare) plant that produces a related compound with similar pharmaceutical activity.

c. Use the structure of the compound to try to make a completely synthetic version of the chemical compound in a lab.

d. Learn more about what the drug is doing in the body and try to design synthetic molecules that might have the same activity.

e. all of the above

USE IT

You are a senator sitting on a committee to review cancer drug development. You have heard testimony from a patient with drug-resistant ovarian cancer, an environmentalist, a college student, and a cancer researcher. Summarize their testimony and explain how each witness contributed to your position on the conflict between saving trees and saving lives.