Question 1

Which of the following best describes the difference between a chromosome, a chromatid, and chromatin?

Accepted Answer

A chromosome is a structure made of DNA and protein, a chromatid is one of two identical halves of a duplicated chromosome, and chromatin is the less condensed form of DNA and protein found during interphase.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the significance of this event?

Accepted Answer

DNA replication occurs during the S phase, ensuring that each daughter cell receives an identical set of chromosomes.

Question 3

Which of the following events distinguishes anaphase from metaphase during mitosis?

Accepted Answer

Sister chromatids are pulled apart toward opposite poles of the cell.

Question 4

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

Accepted Answer

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

Question 5

Which checkpoint in the cell cycle is most critical for determining whether a cell will divide, and what happens if the cell does not pass this checkpoint?

Accepted Answer

The G1 checkpoint; the cell enters a non-dividing state called G0 if it does not pass.

Question 6

Which of the following best explains how the mitotic spindle functions during mitosis?

Accepted Answer

The mitotic spindle is composed of microtubules that attach to kinetochores and help separate sister chromatids during anaphase.

Question 7

Which of the following is a key difference between binary fission in prokaryotes and mitosis in eukaryotes?

Accepted Answer

Binary fission does not involve spindle formation, while mitosis does.

Question 8

Which of the following statements about cyclins and cyclin-dependent kinases (Cdks) is correct?

Accepted Answer

Cdks are only active when bound to cyclins, and together they regulate progression through the cell cycle.

Question 9

A mutation in the ras proto-oncogene leads to which of the following outcomes?

Accepted Answer

Increased cell division due to a hyperactive Ras protein.

Question 10

Which of the following best describes the role of the p53 tumor suppressor gene in preventing cancer?

Accepted Answer

p53 activates DNA repair, halts the cell cycle, and can trigger apoptosis if DNA damage is irreparable.

Question 11

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

Accepted Answer

A point mutation that increases the activity of the protein product.

Question 12

A patient is found to have inherited a mutant allele of the BRCA1 gene. What is the most likely consequence?

Accepted Answer

They have an increased predisposition to developing certain cancers, such as breast cancer.

Question 13

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

Accepted Answer

Older individuals have more exposure to environmental mutagens, leading to the accumulation of multiple mutations required for cancer.

Question 14

Which of the following is NOT a function of tumor-suppressor proteins?

Accepted Answer

Stimulating cell division in response to growth factors.

Question 15

A researcher observes that a cell has entered mitosis but fails to separate its sister chromatids. Which checkpoint likely failed?

Accepted Answer

M checkpoint

Question 16

Which of the following best describes the process of metastasis?

Accepted Answer

The spread of cancer cells to distant parts of the body, forming secondary tumors.

Question 17

Which equation best represents the change in chromosome number during mitosis in a human somatic cell?

Accepted Answer

$$2n \rightarrow 4n \rightarrow 2n$$

Question 18

Which of the following is a real-world example of cell division for tissue renewal?

Accepted Answer

The healing of a skin wound after an injury.

Question 19

Which of the following best explains why chemotherapeutic drugs often cause side effects such as hair loss and nausea?

Accepted Answer

They target all rapidly dividing cells, including normal cells in hair follicles and the digestive tract.

The Cell Cycle and Molecular Biology of Cancer: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard