Question 1

Which of the following best describes the primary function of kinesin in neuronal cells?

Accepted Answer

Kinesin moves vesicles and organelles toward the plus end of microtubules, facilitating anterograde transport.

Question 2

A vesicle is observed moving away from the centrosome along a microtubule. Which motor protein is most likely responsible for this movement, and what is the direction called?

Accepted Answer

Kinesin; anterograde transport

Question 3

The axoneme of a typical motile cilium has which microtubule arrangement?

Accepted Answer

$$9 + 2$$

Question 4

Which of the following is TRUE regarding the movement of cilia and flagella?

Accepted Answer

Cilia move with a power and recovery stroke, while flagella move with a propagated bending motion.

Question 5

A mutation disrupts the central pair of microtubules in the axoneme of a cilium. What is the most likely consequence?

Accepted Answer

The cilium will become non-motile.

Question 6

Which protein is responsible for the sliding of microtubule doublets in the axoneme, leading to the bending of cilia and flagella?

Accepted Answer

Dynein

Question 7

What is the role of nexin in the axoneme of cilia and flagella?

Accepted Answer

It forms cross-links between microtubule doublets, restricting their sliding and converting it into bending.

Question 8

If a vesicle is being transported from the Golgi complex toward the cell periphery, which motor protein and direction are involved?

Accepted Answer

Kinesin; toward the plus end

Question 9

A kinesin molecule takes steps of approximately $$8\ \mathrm{nm}$$ each. If a vesicle moves at $$2\ \mu\mathrm{m}/\mathrm{sec}$$, how many steps does kinesin take per second?

Accepted Answer

$$250\ 	ext{steps/sec}$$

Question 10

Which of the following best explains why primary cilia are non-motile?

Accepted Answer

They lack the central pair of microtubules, having a $$9 + 0$$ arrangement.

Question 11

During intraflagellar transport (IFT), which motor protein is responsible for moving materials toward the tip of the flagellum?

Accepted Answer

Kinesin

Question 12

Which of the following statements about microtubule-based motility is CORRECT?

Accepted Answer

It is responsible for the movement of chromosomes during cell division.

Question 13

Which of the following is a specialized form of cell motility that involves the shortening of muscle cells?

Accepted Answer

Contractility

Question 14

What is the main difference between the movement generated by cilia and that generated by flagella?

Accepted Answer

Cilia generate force parallel to the cell surface with a power and recovery stroke, while flagella generate force parallel to the flagellum with a propagated bending motion.

Question 15

Which of the following is NOT a function of cytoplasmic dynein?

Accepted Answer

Anterograde transport of vesicles toward the plus end of microtubules

Question 16

Which of the following best describes the processivity of kinesin?

Accepted Answer

Kinesin can move long distances along a microtubule without detaching.

Question 17

Which of the following is required for the bending of cilia and flagella?

Accepted Answer

ATP hydrolysis by dynein

Question 18

Which of the following statements about the basal body of cilia and flagella is CORRECT?

Accepted Answer

It resembles a centriole with nine triplet microtubules.

Question 19

Which of the following best explains the reciprocal bending of cilia and flagella?

Accepted Answer

It is a rebound force generated by the connective hold of the nexin cross-link proteins.

Cellular Movement: Motility and Contractility – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard