Question 1

Which of the following best describes the role of microtubules in the movement of cilia and flagella in eukaryotic cells?

Accepted Answer

Microtubules form the axoneme, whose sliding driven by dynein causes bending and movement of cilia and flagella.

Question 2

During fast axonal transport, which motor protein is responsible for moving vesicles toward the synapse (plus end of microtubules), and what is the direction called?

Accepted Answer

Kinesin; anterograde transport

Question 3

Which structural feature is shared by both cilia and flagella in eukaryotic cells?

Accepted Answer

A 9 + 2 arrangement of microtubules in the axoneme

Question 4

Which of the following statements about kinesin movement along microtubules is correct?

Accepted Answer

Kinesin movement resembles 'walking,' with its two globular head domains taking turns as the front foot.

Question 5

What is the primary function of axonemal dynein in cilia and flagella?

Accepted Answer

To slide adjacent microtubule doublets against each other, causing bending

Question 6

Which of the following best explains why microtubule-based motors are crucial for vesicle transport in the endomembrane system?

Accepted Answer

They dynamically shape organelles and move vesicles along microtubule tracks between compartments.

Question 7

A mutation disrupts the radial spokes in the axoneme of a cilium. What is the most likely consequence?

Accepted Answer

The cilium will be unable to bend properly due to impaired transmission of sliding forces.

Question 8

Which of the following is TRUE regarding the difference between primary cilia and motile cilia?

Accepted Answer

Primary cilia have a 9 + 0 structure and are used in sensory functions, while motile cilia have a 9 + 2 structure and are used for movement.

Question 9

Which equation best represents the cycle of ATP hydrolysis by motor proteins such as kinesin and dynein?

Accepted Answer

$$ \mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i} $$

Question 10

A patient has a genetic defect in axonemal dynein. Which symptom would most likely be observed?

Accepted Answer

Reduced ability to move mucus out of the respiratory tract due to immotile cilia

Question 11

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

Accepted Answer

It is structurally similar to a centriole, with nine sets of triplet microtubules.

Question 12

Which of the following best describes the difference between microtubule-based and microfilament-based motility?

Accepted Answer

Microtubule-based motility involves movement along rigid tracks, such as axonal transport, while microfilament-based motility involves actin and is exemplified by muscle contraction.

Question 13

Which of the following is a function of the light chains in kinesin structure?

Accepted Answer

They connect the heavy chains to the tail and are associated with cargo binding.

Question 14

Which of the following motor proteins is responsible for retrograde transport in neurons, moving cargo toward the minus end of microtubules?

Accepted Answer

Cytoplasmic dynein

Question 15

Which of the following statements about the axoneme structure in cilia and flagella is correct?

Accepted Answer

Each outer doublet consists of one complete A tubule and one incomplete B tubule.

Question 16

Which of the following is a direct consequence of doublet sliding within the axoneme?

Accepted Answer

Cilia and flagella bend, generating movement.

Question 17

Which of the following best explains why defects in primary cilia can result in disorders such as deafness and left-right asymmetry reversals?

Accepted Answer

Primary cilia are involved in sensory signaling and developmental patterning.

Question 18

Which of the following is TRUE about the movement of motor proteins along microtubules?

Accepted Answer

Kinesins generally move toward the plus end, while dyneins move toward the minus end.

Question 19

Which of the following best describes the role of the basal body in cilia and flagella?

Accepted Answer

It anchors the axoneme and determines the pattern of microtubule arrangement.

Cellular Movement: Motility and Contractility – Study Notes

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