Question 1

Which of the following best describes the difference between a genome and a chromosome in eukaryotic cells?

Accepted Answer

A genome is the full genetic information of an organism, while a chromosome is a single DNA molecule and associated proteins.

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 a complete set of chromosomes.

Question 3

A researcher observes a cell with condensed chromosomes, a fragmented nuclear envelope, and kinetochores attached to microtubules. Which stage of mitosis is this cell most likely in?

Accepted Answer

Prometaphase

Question 4

What is the primary function of the mitotic spindle during mitosis?

Accepted Answer

To separate sister chromatids and ensure their distribution to daughter cells

Question 5

Which checkpoint in the cell cycle ensures that all chromosomes are properly attached to the spindle before anaphase begins?

Accepted Answer

M checkpoint

Question 6

If a cell bypasses the G2 checkpoint without repairing DNA damage, what are two possible consequences?

Accepted Answer

Aneuploidy and increased risk of cancer

Question 7

Which of the following best explains why chemotherapy drugs like Taxol are effective against cancer cells?

Accepted Answer

They freeze the mitotic spindle by preventing microtubule depolymerization, blocking cell division.

Question 8

In animal cells, cytokinesis is accomplished by which of the following mechanisms?

Accepted Answer

Pinching of the plasma membrane by a contractile ring of actin and myosin

Question 9

Which of the following statements about HeLa cells is correct?

Accepted Answer

HeLa cells are cancer cells taken from Henrietta Lacks without her consent and have been widely used in research.

Question 10

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

Accepted Answer

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

Question 11

A scientist observes that a group of animal cells stop dividing when they become crowded and touch each other. Which phenomenon is being observed?

Accepted Answer

Density-dependent inhibition

Question 12

Which of the following events distinguishes plant cell cytokinesis from animal cell cytokinesis?

Accepted Answer

Formation of a cell plate from vesicles containing cell wall materials

Question 13

Which of the following is true about binary fission in prokaryotes?

Accepted Answer

Binary fission involves concurrent DNA replication and partitioning of chromosomes to cell poles.

Question 14

A cell is observed with chromosomes aligned at the metaphase plate, with spindle fibers attached to kinetochores. What is the next major event that will occur?

Accepted Answer

Sister chromatids will be separated and pulled toward opposite poles.

Question 15

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

Accepted Answer

They no longer respond to normal cell cycle regulatory signals and checkpoints.

Question 16

Which of the following equations best represents the number of DNA molecules in a cell during metaphase if the diploid number is $$2n$$ and each chromosome has two sister chromatids?

Accepted Answer

$$4n$$

Question 17

Which protein complex is responsible for cleaving cohesins and allowing sister chromatids to separate during anaphase?

Accepted Answer

Separase

Question 18

A mutation causes a cell to lose its ability to form kinetochores. Which stage of mitosis would be directly affected?

Accepted Answer

Prometaphase

Question 19

Which of the following best describes the G0 phase of the cell cycle?

Accepted Answer

A non-dividing stage where cells have left the cell cycle, sometimes reversibly.

Question 20

Which of the following is a real-world ethical issue highlighted by the story of Henrietta Lacks and HeLa cells?

Accepted Answer

The collection and use of human biological materials without informed consent.

The Cell Cycle: Structure, Regulation, and Clinical Relevance

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