Question 1

Which of the following statements best describes the difference between cell division in unicellular and multicellular organisms?

Accepted Answer

In unicellular organisms, cell division results in the reproduction of the entire organism, while in multicellular organisms, it allows for growth, development, and replacement of dead cells.

Question 2

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

Accepted Answer

S phase

Question 3

Which structure is responsible for joining two sister chromatids together during mitosis?

Accepted Answer

Centromere

Question 4

A researcher observes a cell with chromosomes aligned at the equator of the cell, spindle fibers attached, and the nuclear envelope dissolved. Which stage of mitosis is this cell in?

Accepted Answer

Metaphase

Question 5

Which of the following best explains why cancer cells continue to divide even when crowded, unlike normal cells?

Accepted Answer

Cancer cells do not respond to density-dependent inhibition, allowing them to divide without regard to cell density.

Question 6

In animal cells, cytokinesis is accomplished by the formation of a contractile ring made of which cytoskeletal element?

Accepted Answer

Actin microfilaments

Question 7

If a human somatic cell contains 46 chromosomes, how many chromosomes will each daughter cell have after mitosis?

Accepted Answer

46

Question 8

Which event marks the beginning of anaphase during mitosis?

Accepted Answer

Sister chromatids separate and move toward opposite poles.

Question 9

A cell is observed to have a well-defined nucleus, two centrosomes, and loosely packed chromatin fibers containing twice the genome. Which phase of the cell cycle is this cell most likely in?

Accepted Answer

G$$_2$$ phase

Question 10

Which of the following is TRUE regarding the process of binary fission in prokaryotes?

Accepted Answer

A cell wall forms between two chromosomes, dividing the original cell into two daughter cells.

Question 11

Which of the following best describes the role of the kinetochore during mitosis?

Accepted Answer

It is a protein structure at the centromere that attaches chromosomes to spindle fibers.

Question 12

Which phase of mitosis is characterized by the reformation of the nuclear envelope and the decondensation of chromosomes?

Accepted Answer

Telophase

Question 13

In plant cells, cytokinesis occurs by the formation of a cell plate. Which organelle is primarily involved in this process?

Accepted Answer

Golgi apparatus

Question 14

Which of the following factors can inhibit cell division in cultured mammalian cells?

Accepted Answer

High cell density leading to density-dependent inhibition

Question 15

A tumor is considered malignant only if it has the ability to:

Accepted Answer

Invade surrounding tissues and spread to other parts of the body (metastasize)

Question 16

Which of the following best describes the genetic content of gametes compared to somatic cells in humans?

Accepted Answer

Gametes have half the number of chromosomes as somatic cells.

Question 17

Which of the following equations correctly represents the chromosome number restoration during fertilization in humans?

Accepted Answer

$$23 + 23 = 46$$

Question 18

During which stage of mitosis do spindle fibers attach to kinetochores on chromosomes?

Accepted Answer

Prometaphase

Question 19

A cell is observed to have stopped dividing and is not preparing for division. It is most likely in which phase?

Accepted Answer

G$$_0$$ phase

Question 20

Which checkpoint in the cell cycle determines whether a cell will proceed to DNA synthesis or exit into a nondividing state?

Accepted Answer

G$$_1$$ checkpoint (restriction point)

Lec 10 - Cellular Reproduction: Mechanisms and Regulation

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