Question 1

Transcription ceases as chromosome condensation occurs.

Accepted Answer

During chromosome condensation, the DNA becomes highly compacted and tightly coiled, making it inaccessible to cellular machinery such as the enzymes responsible for transcription. Therefore, transcription cannot occur during this process.

Question 2

Re-formation of the nuclear envelope occurs as the result of cyclin B destruction, which allows phosphatases to dephosphorylate nuclear envelope lamins.

Accepted Answer

Re-formation of the nuclear envelope occurs as a result of cyclin B destruction, which allows the activation of nuclear envelope lamins by dephosphorylation through phosphatases.

Question 3

A mutant cyclin B that is resistant to degradation by protease, but is otherwise active, would block the metaphase-to-anaphase transition.

Accepted Answer

The answer of A mutant cyclin B that is resistant...

Question 4

The metaphase-to-anaphase transition in animal cells is triggered by the breakdown of cyclin B.

Accepted Answer

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Question 5

In what phase(s) of the cell cycle does growth typically occur?

Accepted Answer

The answer of In what phase(s) of the cell cycle...

Question 6

What does the spindle assembly checkpoint prevent?

Accepted Answer

The answer of What does the spindle assembly checkpoint prevent?...

Question 7

Identify the four different molecular mechanisms by which the activity of cyclin-dependent kinases is regulated after they are synthesized.

Accepted Answer

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Question 8

To investigate the role of APC/C ubiquitin ligase in an experimental cell culture model, you are able to insert a plasmid gene encoding a mutant APC/C protein that is always active (i.e., cannot be inhibited). What would be the predicted outcome on the cells that received this mutant APC/C?

Accepted Answer

The answer of To investigate the role of APC/C ubiquitin...

Question 9

How is DNA replication prevented from recurring in a single cell cycle?

Accepted Answer

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Question 10

How is the anaphase-promoting complex/cyclosome (APC/C) activated?

Accepted Answer

The answer of How is the anaphase-promoting complex/cyclosome (APC/C) activated?...

Question 11

Dephosphorylation of proteins that were phosphorylated during prophase leads to what three telophase events?

Accepted Answer

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Question 12

What determines the location of the contractile ring of filaments that mediate cytokinesis in an animal cell?

Accepted Answer

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Question 13

Cytokinesis occurs in a plane that passes through which area of a cell?

Accepted Answer

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Question 14

Interphase is defined as

Accepted Answer

Interphase is the phase of the cell cycle when the cell is growing and preparing for cell division. It consists of three sub-phases: G₁, G₂, and S phase. Quiescent phase (also known as G0 phase) is a separate phase outside of interphase, and M phase is the phase of cell division. Therefore, the best choice is B, as it includes all three sub-phases of interphase.

Question 15

The phase of the cell cycle that corresponds to the interval between mitosis and initiation of DNA replication is referred to as the

Accepted Answer

The G1 phase is the first gap phase after mitosis and before the S phase, where the cell grows and prepares for DNA replication.

Question 16

You perform an experiment by incubating a radiolabeled nucleotide into the medium of a culture of cells. The cells that take up the radiolabel would be expected to be in what phase of the cell cycle?

Accepted Answer

During S phase, DNA replication occurs and new nucleotides are incorporated into newly synthesized DNA strands. Therefore, cells in S phase actively incorporate nucleotides into their DNA and would be the most likely to take up radiolabeled nucleotides in this experiment.

Question 17

In which of the following cell types do G₁ and G₂ not take place?

Accepted Answer

Early embryonic cells often skip the G1 and G2 phases to rapidly divide and increase cell number, focusing on DNA replication and mitosis.

Question 18

DNA content can be found using a method of flow cytometry that can determine 2n or 4n states of cells based on cell counting and fluorescent labeling of DNA. Which of the following phases would be identified through flow cytometry as 2n?

Accepted Answer

The answer of DNA content can be found using a...

Question 19

In the absence of growth factor, most animal cells will stop the cell cycle at a restriction point in what stage?

Accepted Answer

The restriction point is located in the late G1 phase and is also called the G1 checkpoint. It ensures that the cell is large enough, has enough nutrients and energy, and lacks DNA damage before entering S phase. If the conditions are not met, the cell will stop the cell cycle at the restriction point and enter a quiescent state called G0 phase. M phase refers to the mitotic phase where cell division occurs, and G₂ phase does not exist in the cell cycle.

Question 20

In yeast, START triggers the progression from G₁ to S. Which of the following are involved in regulating START?

Accepted Answer

Nutrients, mating factors, and cell size are all involved in regulating START in yeast. Nutrient availability determines if there are enough resources for cell growth and division, mating factors signal whether there are potential mating partners present, and cell size determines if the cell is big enough to divide. Thus, all of the above factors are important in regulating START in yeast.

Quiz 18: The Cell Cycle