Q: Which of the following equations best represents the relationship between cyclin concentration and MPF activity during the cell cycle?

$$\text{MPF activity} \propto \text{Cyclin concentration}$$

Question 1

Which of the following best describes the difference in cytokinesis between animal and plant cells?

Accepted Answer

Animal cells form a cleavage furrow, while plant cells form a cell plate.

Question 2

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 3

Which of the following is a key feature of binary fission in prokaryotes?

Accepted Answer

The chromosome replicates and the plasma membrane pinches inward to divide the cell.

Question 4

What is the role of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

They must be attached to a cyclin to be active and help regulate cell cycle progression.

Question 5

A researcher fuses a cell in S phase with a cell in G1 phase. What is the most likely outcome for the G1 nucleus?

Accepted Answer

The G1 nucleus will immediately enter S phase and begin DNA synthesis.

Question 6

Which checkpoint is considered the most important for many cells, determining whether the cell will divide?

Accepted Answer

$$G_1$$ checkpoint

Question 7

What is the function of the maturation-promoting factor (MPF) in the cell cycle?

Accepted Answer

It triggers a cell’s passage past the $$G_2$$ checkpoint into the M phase.

Question 8

Which of the following is an example of an internal signal that regulates the cell cycle?

Accepted Answer

Cells will not begin anaphase until all chromosomes are properly attached to the spindle at the metaphase plate.

Question 9

Which of the following statements about cancer cells is correct?

Accepted Answer

Cancer cells do not exhibit density-dependent inhibition or anchorage dependence.

Question 10

A patient is being treated with chemotherapy for a metastatic tumor. Which of the following best explains why the patient experiences side effects such as hair loss and nausea?

Accepted Answer

Chemotherapeutic drugs target all rapidly dividing cells, including normal cells like hair follicles and cells lining the digestive tract.

Question 11

Which of the following best describes the evolutionary relationship between binary fission and mitosis?

Accepted Answer

Mitosis likely evolved from binary fission, as prokaryotes evolved before eukaryotes.

Question 12

A cell is observed to have condensed chromosomes aligned at the metaphase plate. Which phase of mitosis is this cell in?

Accepted Answer

Metaphase

Question 13

Which of the following equations best represents the relationship between cyclin concentration and MPF activity during the cell cycle?

Accepted Answer

$$	ext{MPF activity} \propto 	ext{Cyclin concentration}$$

Question 14

If a cell does not receive a go-ahead signal at the $$G_1$$ checkpoint, what is the most likely fate of the cell?

Accepted Answer

It will exit the cell cycle and enter a nondividing state called $$G_0.$$

Question 15

Which of the following is a real-world example of a growth factor influencing cell division?

Accepted Answer

Platelet-derived growth factor (PDGF) stimulates fibroblast division during wound healing.

Question 16

A scientist observes that a certain cell line continues to divide even when crowded and not attached to a substratum. What is the most likely explanation?

Accepted Answer

The cells are cancerous and have lost normal cell cycle regulation.

Question 17

Which of the following best explains why daughter cells produced by mitosis are genetically identical to the parent cell?

Accepted Answer

DNA is replicated during S phase, and each daughter cell receives an identical set of chromosomes.

Question 18

Which of the following statements about the cell cycle control system is correct?

Accepted Answer

It is regulated by both internal and external signals at specific checkpoints.

Question 19

A cell is exposed to high-energy radiation, which damages its DNA. What is the most likely effect on the cell cycle?

Accepted Answer

The cell cycle will be halted at a checkpoint to allow for DNA repair.

Question 20

Which of the following best describes metastasis in cancer?

Accepted Answer

The spread of cancer cells to other parts of the body, forming additional tumors.

The Cell Cycle: Regulation, Mechanisms, and Cancer

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