Question 1

Which of the following statements best describes the role of gamma-tubulin ($$\gamma-$$tubulin) in microtubule organization within animal cells?

Accepted Answer

It forms a stable platform at the microtubule organizing center (MTOC) to nucleate and anchor the minus ends of microtubules.

Question 2

A scientist observes that a certain eukaryotic cell can no longer move vesicles toward the cell periphery. Which cytoskeletal motor protein is most likely defective?

Accepted Answer

Kinesin

Question 3

Which of the following best explains why microtubules are considered 'dynamic' structures in the cell?

Accepted Answer

They can rapidly grow and shrink by the addition and removal of tubulin dimers, especially at the plus end.

Question 4

During mitosis, the reorganization of microtubules into a bipolar spindle is essential for which cellular process?

Accepted Answer

Separation of sister chromatids during anaphase

Question 5

Which of the following is a key difference between actin filaments and intermediate filaments?

Accepted Answer

Actin filaments are dynamic and have polarity, while intermediate filaments are more stable and lack polarity.

Question 6

A mutation in the gene encoding dynein would most directly affect which of the following cellular processes?

Accepted Answer

Movement of cilia and flagella

Question 7

Which cytoskeletal element is most directly responsible for providing tensile strength to epithelial cells, allowing them to resist mechanical stress?

Accepted Answer

Intermediate filaments (keratins)

Question 8

In a cell, which of the following best describes the directionality of kinesin and dynein movement along microtubules?

Accepted Answer

Kinesin moves toward the plus end, dynein toward the minus end.

Question 9

Which of the following best explains why plant cells lack centrioles but can still organize microtubules?

Accepted Answer

Plant cells have alternative microtubule organizing centers (MTOCs) that do not require centrioles.

Question 10

A patient has a genetic disorder affecting the structure of their keratin proteins. Which tissue is most likely to be affected?

Accepted Answer

Epithelial tissue (e.g., skin)

Question 11

Which of the following best describes the molecular composition of a microtubule?

Accepted Answer

A hollow tube composed of 13 protofilaments made from alpha- and beta-tubulin dimers

Question 12

Which cytoskeletal structure is most directly involved in the formation of the contractile ring during cytokinesis in animal cells?

Accepted Answer

Actin filaments

Question 13

Which of the following scenarios would most likely result from a defect in the assembly of microtubule doublets?

Accepted Answer

Defective cilia and flagella movement

Question 14

Which of the following is a function shared by both actin filaments and microtubules, but not by intermediate filaments?

Accepted Answer

Dynamic assembly and disassembly for cell shape changes

Question 15

A researcher adds a drug to cells that prevents GTP hydrolysis on beta-tubulin. What is the most likely effect on microtubule dynamics?

Accepted Answer

Microtubules will become more stable and less likely to shrink.

Question 16

Which of the following best explains why intermediate filaments are considered less dynamic than microtubules or actin filaments?

Accepted Answer

They lack a defined plus and minus end, and their subunits rarely exchange once assembled.

Question 17

Which of the following best describes the role of actin filaments in non-muscle cells?

Accepted Answer

They provide structural support to the plasma membrane and are involved in cell migration and shape changes.

Question 18

Which of the following is a correct statement about the polarity of cytoskeletal filaments?

Accepted Answer

Both actin filaments and microtubules have plus and minus ends, while intermediate filaments do not.

Question 19

A cell is observed to have a defect in lamins. Which cellular structure is most likely to be compromised?

Accepted Answer

The nuclear envelope

LEC 8:The Cytoskeleton: Structure and Function in Eukaryotic Cells

Study Guide - Practice Questions

Study Guide - Flashcards