Question 1

Which protein complex is responsible for holding sister chromatids together until anaphase during mitosis?

Accepted Answer

Cohesin

Question 2

What triggers the destruction of securin, leading to the activation of separase and the onset of anaphase?

Accepted Answer

The anaphase-promoting complex (APC)

Question 3

During which phase of mitosis do chromosomes align at the equatorial region of the cell?

Accepted Answer

Metaphase

Question 4

Which of the following best describes the role of microtubules during metaphase?

Accepted Answer

They generate tension by attaching to kinetochores and pulling equally in opposite directions

Question 5

What is the main difference between anaphase A and anaphase B during mitosis?

Accepted Answer

Anaphase A involves shortening of kinetochore microtubules, while anaphase B involves movement of spindle poles apart.

Question 6

Which event marks the completion of nuclear division in mitosis?

Accepted Answer

Nuclear envelope reforms around separated chromosomes

Question 7

In animal cells, what structure is responsible for physically dividing the cytoplasm during cytokinesis?

Accepted Answer

Actin-based contractile ring

Question 8

Why do plant cells form a cell plate during cytokinesis instead of a cleavage furrow?

Accepted Answer

The rigid cell wall prevents furrow ingression

Question 9

Which checkpoint is most critical for determining whether a cell will proceed to divide or enter a non-dividing state?

Accepted Answer

G1/S checkpoint

Question 10

A cell receives no external growth signals during G1. What is the most likely outcome?

Accepted Answer

The cell will enter the G0 phase

Question 11

Which enzyme is directly responsible for cleaving cohesin and allowing sister chromatids to separate?

Accepted Answer

Separase

Question 12

What would happen if securin was not degraded at the onset of anaphase?

Accepted Answer

Sister chromatids would fail to separate

Question 13

Which of the following best describes the movement of chromosomes during metaphase?

Accepted Answer

Jerky back-and-forth motion until stabilized at the metaphase plate

Question 14

Which of the following is a direct result of the activation of the anaphase-promoting complex (APC)?

Accepted Answer

Securin is degraded

Question 15

Which process is responsible for the reappearance of nucleoli and the de-condensation of chromosomes?

Accepted Answer

Telophase

Question 16

A mutation prevents the formation of the actin-based contractile ring in an animal cell. What is the most likely consequence?

Accepted Answer

The cell will not complete cytokinesis

Question 17

Which of the following best explains why progression through the cell cycle is unidirectional?

Accepted Answer

Checkpoints prevent reversal and ensure each stage is completed before moving forward

Question 18

Which of the following is a real-world example of a growth factor that can trigger cell division?

Accepted Answer

Platelet-derived growth factor (PDGF)

Question 19

If a drug inhibits the depolymerization of spindle microtubules during telophase, what is the most likely effect?

Accepted Answer

Spindle remnants may persist, interfering with nuclear envelope reformation

Question 20

Which checkpoint ensures that all chromosomes are properly attached to the spindle before proceeding with chromatid separation?

Accepted Answer

M checkpoint

LEC 16: Mitosis, Chromosome Segregation, and Cell Cycle Control

Study Guide - Practice Questions