Question 1

Which of the following best describes the relationship between chromatin, chromosomes, and the genome in a eukaryotic cell?

Accepted Answer

Chromosomes are made of chromatin, which is a complex of DNA and protein, and the genome is the complete set of genetic material in a cell.

Question 2

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

Accepted Answer

S phase

Question 3

A scientist observes a cell with condensed chromosomes aligned at the center of the cell, spindle fibers attached to kinetochores, and centrosomes at opposite poles. Which phase of mitosis is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following statements about binary fission in bacteria is correct?

Accepted Answer

Binary fission results in two genetically identical daughter cells by replicating the chromosome and dividing the cell.

Question 5

Which checkpoint in the cell cycle is considered the most important for determining whether a cell will divide?

Accepted Answer

G1 checkpoint

Question 6

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

Accepted Answer

Cdks phosphorylate target proteins only when bound to cyclins, regulating progression through the cell cycle.

Question 7

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

Accepted Answer

Cytokinesis in an animal cell

Question 8

Which of the following best explains why cancer cells can form tumors?

Accepted Answer

Cancer cells ignore normal cell cycle controls, do not require growth factors, and can divide uncontrollably.

Question 9

If a cell does not receive a go-ahead signal at the G1 checkpoint, what is the most likely outcome?

Accepted Answer

The cell will exit the cell cycle and enter the G0 phase.

Question 10

Which of the following events occurs during anaphase of mitosis?

Accepted Answer

Sister chromatids separate and move toward opposite poles.

Question 11

A researcher adds platelet-derived growth factor (PDGF) to a culture of fibroblasts. What is the expected result?

Accepted Answer

The fibroblasts will begin to divide in response to the external growth factor.

Question 12

Which of the following equations correctly represents the number of chromosomes and DNA molecules in a human somatic cell during G2 phase?

Accepted Answer

$$46$$ chromosomes and $$92$$ DNA molecules

Question 13

Which structure is responsible for organizing the mitotic spindle in animal cells?

Accepted Answer

Centrosome

Question 14

What is the main difference between somatic cells and gametes in terms of chromosome number?

Accepted Answer

Somatic cells have two sets of chromosomes, while gametes have one set.

Question 15

Which of the following best describes the function of the mitotic spindle during cell division?

Accepted Answer

It organizes and separates chromosomes during mitosis.

Question 16

A mutation causes a cell to skip the M checkpoint. What is a likely consequence?

Accepted Answer

The cell may divide with an incorrect number of chromosomes.

Question 17

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

Accepted Answer

Healing of a skin wound through mitosis of skin cells

Question 18

Which of the following statements about MPF (maturation-promoting factor) is correct?

Accepted Answer

MPF is a protein complex that triggers passage from G2 to M phase.

Question 19

Which of the following mechanisms ensures that daughter cells have the correct number of chromosomes after mitosis?

Accepted Answer

Attachment of all chromosomes to the spindle at the metaphase plate before anaphase begins

Question 20

A patient is treated with a chemotherapy drug that inhibits microtubule polymerization. Which stage of the cell cycle will be most directly affected?

Accepted Answer

M phase (mitosis)

The Cell Cycle: Mechanisms and Regulation

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