Question 1

Which of the following best describes the difference between somatic cells and gametes in humans?

Accepted Answer

Somatic cells are diploid and produced by mitosis, while gametes are haploid and produced by meiosis.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the result for each chromosome?

Accepted Answer

DNA replication occurs during the S phase, resulting in two identical sister chromatids per chromosome.

Question 3

A researcher observes a cell with condensed chromosomes aligned at the metaphase plate, spindle fibers attached to kinetochores, and no nuclear envelope. Which phase of mitosis is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following statements about the mitotic spindle is correct?

Accepted Answer

The mitotic spindle is composed of microtubules, forms during prophase, and is responsible for separating sister chromatids.

Question 5

A patient is diagnosed with a tumor that has invaded surrounding tissues and spread to other organs. Which terms best describe this tumor?

Accepted Answer

Malignant tumor; metastasis

Question 6

Which checkpoint is considered the 'restriction point' in the cell cycle, and why is it especially important?

Accepted Answer

The G1 checkpoint, because it determines whether the cell will proceed with division or enter the G0 phase.

Question 7

Which of the following best explains why chemotherapy often causes hair loss and gastrointestinal side effects?

Accepted Answer

Chemotherapy targets rapidly dividing cells, and hair follicle and intestinal lining cells divide frequently.

Question 8

Which of the following equations correctly represents the diploid ($$2n) $$and haploid ($$n) $$chromosome numbers in humans?

Accepted Answer

$$2n = 46$$, $$n = 23$$

Question 9

A scientist observes that a cell has exited the cell cycle and is not dividing. Which phase is this cell most likely in, and what type of cell is most likely to remain in this phase permanently?

Accepted Answer

G0 phase; mature nerve cell

Question 10

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

Accepted Answer

Cdks are present at constant concentrations but require binding to cyclins, whose concentrations fluctuate, to become active.

Question 11

Which of the following events occurs during anaphase of mitosis?

Accepted Answer

Sister chromatids separate and move toward opposite poles as kinetochore microtubules shorten.

Question 12

In plant cells, cytokinesis is characterized by the formation of which structure, and what is its function?

Accepted Answer

Cell plate; forms a new cell wall between the daughter cells.

Question 13

Which of the following best explains how platelet-derived growth factor (PDGF) stimulates wound healing?

Accepted Answer

PDGF is released by platelets and stimulates fibroblasts to divide and repair connective tissue.

Question 14

A cell is observed to lack density-dependent inhibition and anchorage dependence. What is the most likely identity of this cell?

Accepted Answer

A cancer cell

Question 15

Which of the following best describes the process of binary fission in prokaryotes?

Accepted Answer

The chromosome replicates, and the plasma membrane pinches inward to divide the cell into two.

Question 16

Which of the following scenarios would most likely trigger apoptosis in a cell?

Accepted Answer

A cell detects irreparable DNA damage at the G2 checkpoint.

Question 17

Which of the following is true regarding the maturation-promoting factor (MPF) and its role in the cell cycle?

Accepted Answer

MPF is formed by the combination of cyclin and Cdk, and its activity peaks during the M phase to trigger mitosis.

Question 18

A cell is observed with chromosomes that each consist of two identical chromatids. During which stages of the cell cycle does this occur?

Accepted Answer

From the end of S phase through metaphase of mitosis

Question 19

Which of the following best explains why cancer cells can form tumors while normal cells do not?

Accepted Answer

Cancer cells lack normal cell cycle regulation, do not respond to density-dependent inhibition or anchorage dependence, and can divide uncontrollably.

Question 20

Which of the following best describes the function of kinetochores during mitosis?

Accepted Answer

Kinetochores are protein complexes at centromeres that attach chromosomes to spindle microtubules, allowing movement during mitosis.

CHP12

Guida di studio - Domande di pratica

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