Question 1

Which of the following best describes the primary function of the cytoskeleton in eukaryotic cells?

Accepted Answer

It organizes structures and activities in the cell, providing mechanical support and enabling cell motility.

Question 2

Microtubules are composed of which protein subunits?

Accepted Answer

Tubulin dimers, consisting of $$\alpha-$$tubulin and $$\beta-$$tubulin

Question 3

Which cytoskeletal element is primarily responsible for resisting tension (pulling forces) within the cell?

Accepted Answer

Intermediate filaments

Question 4

A mutation in the gene encoding dynein would most likely affect which cellular process?

Accepted Answer

Bending movements of cilia and flagella

Question 5

Which of the following best explains why males with Kartagener’s syndrome are often infertile and prone to lung infections?

Accepted Answer

They have a genetic defect affecting dynein arms, resulting in immotile cilia and flagella.

Question 6

Which structure is found at the base of a eukaryotic flagellum and is structurally similar to a centriole?

Accepted Answer

Basal body

Question 7

What is the arrangement of microtubules in a typical motile cilium or flagellum?

Accepted Answer

A '9 + 2' pattern: nine doublets in a ring with two single microtubules in the center

Question 8

Which cytoskeletal element is most directly involved in the movement of vesicles containing neurotransmitters to the tips of axons?

Accepted Answer

Microtubules

Question 9

Which of the following best describes the role of actin and myosin in amoeboid movement?

Accepted Answer

They interact to cause localized contractions, forming pseudopodia for crawling.

Question 10

A scientist observes a eukaryotic cell with a highly dynamic cytoskeleton that can be quickly dismantled and reassembled. Which cytoskeletal elements are most likely responsible for this behavior?

Accepted Answer

Microtubules and microfilaments

Question 11

Which of the following is a function of cortical microfilaments in animal cells?

Accepted Answer

They help support the cell’s shape just inside the plasma membrane.

Question 12

Which cytoskeletal element is most likely to persist after a cell dies, as seen in the outer layer of human skin?

Accepted Answer

Intermediate filaments (keratin)

Question 13

Which of the following best explains the difference in movement between cilia and flagella?

Accepted Answer

Flagella move with an undulating motion, while cilia move with alternating power and recovery strokes.

Question 14

Which of the following is NOT a function of microtubules?

Accepted Answer

Forming the core of microvilli in intestinal cells

Question 15

A cell is observed to have a single, nonmotile cilium with membrane proteins that transmit signals from the environment. What is this structure called?

Accepted Answer

Primary cilium

Question 16

Which cytoskeletal element is most directly involved in cytoplasmic streaming in plant cells?

Accepted Answer

Microfilaments (actin filaments)

Question 17

Which of the following best describes the structural difference between microtubules and microfilaments?

Accepted Answer

Microtubules are hollow tubes made of tubulin; microfilaments are solid rods made of actin.

Question 18

Which of the following statements about centrosomes is correct?

Accepted Answer

They are regions near the nucleus where microtubules are initiated in animal cells.

Question 19

Which cytoskeletal element is most likely to anchor the nucleus in place within a cell?

Accepted Answer

Intermediate filaments

Question 20

A researcher observes a cell with defective cross-linking proteins in its cilia. Which cellular function is most likely to be impaired?

Accepted Answer

The ability of cilia to bend and move fluid over the cell surface

The Cytoskeleton: Structure, Function, and Dynamics in Eukaryotic Cells

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