Question 1

Which of the following best describes the role of the mitotic spindle during mitosis?

Accepted Answer

It organizes and separates chromosomes by attaching to kinetochores and pulling sister chromatids apart.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the state of the genetic material at this point?

Accepted Answer

S phase; DNA is in the form of chromatin and is being duplicated.

Question 3

A cell is observed with chromosomes aligned at the center of the cell, attached to spindle fibers from opposite poles. Which phase is this, and what is the significance of this arrangement?

Accepted Answer

Metaphase; ensures that each daughter cell will receive an identical set of chromosomes.

Question 4

Which of the following equations correctly represents the change in chromosome number during mitosis in a human somatic cell?

Accepted Answer

$$2n \rightarrow 2n$$

Question 5

What is the primary difference between cytokinesis in plant and animal cells?

Accepted Answer

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

Question 6

Which checkpoint in the cell cycle is most critical for determining whether a cell will proceed to divide or enter a non-dividing state?

Accepted Answer

G1 checkpoint

Question 7

A mutation in the p53 gene can lead to cancer because:

Accepted Answer

p53 normally suppresses the cell cycle in response to DNA damage, preventing the propagation of mutations.

Question 8

Which of the following best explains why cancer cells can divide uncontrollably?

Accepted Answer

They often have mutations in proto-oncogenes and tumor-suppressor genes, disrupting normal cell cycle control.

Question 9

Which of the following is a function of tumor-suppressor proteins?

Accepted Answer

Repairing damaged DNA, controlling cell adhesion, and inhibiting the cell cycle.

Question 10

Binary fission in prokaryotes differs from mitosis in eukaryotes in that:

Accepted Answer

Binary fission does not involve a nucleus or mitotic spindle, while mitosis does.

Question 11

A researcher observes a cell with two sets of chromosomes, each consisting of two sister chromatids joined at the centromere. Which stage of mitosis is this cell most likely in?

Accepted Answer

Prophase

Question 12

Which of the following best describes the function of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

They phosphorylate target proteins to regulate progression through the cell cycle, but only when bound to cyclins.

Question 13

A cell is exposed to a chemical that prevents the breakdown of cohesin proteins. What is the most likely result during mitosis?

Accepted Answer

Sister chromatids will not separate during anaphase.

Question 14

Which of the following genetic changes can convert a proto-oncogene into an oncogene?

Accepted Answer

A mutation that increases the amount or activity of the protein product.

Question 15

If a cell fails to pass the M checkpoint, what is the most likely consequence?

Accepted Answer

The cell will not proceed to anaphase until all chromosomes are properly attached to the spindle.

Question 16

Which of the following best explains why the incidence of cancer increases with age?

Accepted Answer

Multiple mutations are generally needed for full-fledged cancer, and these accumulate over time.

Question 17

A patient inherits a mutant allele of the BRCA1 gene. What is the most likely consequence?

Accepted Answer

They have a higher predisposition to certain cancers, such as breast cancer, due to impaired DNA repair.

Question 18

Which of the following is NOT a function of the p53 protein?

Accepted Answer

Promoting cell division in response to growth factors.

Question 19

Which of the following best describes the relationship between chromatin, chromosomes, and chromatids?

Accepted Answer

Chromatin is the complex of DNA and proteins; chromosomes are condensed chromatin; chromatids are identical copies of a chromosome joined at the centromere.

Question 20

A cell is observed to have a cleavage furrow forming. What process is occurring, and in what type of organism is this most likely?

Accepted Answer

Cytokinesis in an animal cell.

The Cell Cycle and Molecular Biology of Cancer: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard