Question 1

Which of the following best explains why biological membranes are described as 'asymmetrical'?

Accepted Answer

Different types of lipids and proteins are found on the inner and outer leaflets, reflecting specialized functions.

Question 2

A phospholipid molecule contains both hydrophobic and hydrophilic regions. Which term best describes this property?

Accepted Answer

Amphipathic

Question 3

Which factor would most likely increase the fluidity of a cell membrane?

Accepted Answer

Increasing the proportion of unsaturated fatty acid tails

Question 4

A red blood cell is placed in a hypotonic solution. What will happen to the cell?

Accepted Answer

It will swell and may burst due to water influx.

Question 5

Which of the following transport mechanisms requires energy input from ATP hydrolysis?

Accepted Answer

Active transport

Question 6

The Na+/K+ ATPase pump moves sodium and potassium ions across the plasma membrane. What is the net result of one cycle of this pump?

Accepted Answer

3 Na+ out, 2 K+ in, and 1 ATP consumed

Question 7

Which of the following best describes the function of the Golgi apparatus in the endomembrane system?

Accepted Answer

It modifies, sorts, and packages proteins for secretion or delivery to other organelles.

Question 8

Which coat protein is primarily involved in vesicle transport from the ER to the Golgi apparatus?

Accepted Answer

COPII

Question 9

A mutation prevents the addition of the ER retention signal (KDEL sequence) to a protein. What is the most likely consequence?

Accepted Answer

The protein will be secreted from the cell.

Question 10

Which of the following statements about lysosomes is correct?

Accepted Answer

Lysosomes contain hydrolytic enzymes that function best at acidic pH.

Question 11

Which cytoskeletal element is composed of tubulin dimers and is essential for mitotic spindle formation?

Accepted Answer

Microtubules

Question 12

Which motor protein moves toward the plus end of microtubules and is important for anterograde transport in neurons?

Accepted Answer

Kinesin

Question 13

Which of the following drugs disrupts microtubule polymerization and is used in cancer therapy?

Accepted Answer

Colchicine

Question 14

What is the main function of actin microfilaments in cell motility?

Accepted Answer

They enable cell crawling by polymerization and depolymerization at the leading edge.

Question 15

Which of the following best describes the 9 + 2 arrangement in cilia and flagella?

Accepted Answer

9 doublet microtubules surrounding 2 central singlet microtubules

Question 16

Which process involves the engulfment of large particles or cells by the plasma membrane?

Accepted Answer

Phagocytosis

Question 17

A cell is exposed to a toxin that inhibits ATP production. Which transport process will be most directly affected?

Accepted Answer

Active transport of Na+ ions

Question 18

Which equation correctly represents the calculation of osmotic pressure ($$\Pi) in a $$solution?

Accepted Answer

$$\Pi = CRT$$

Question 19

Which of the following is a function of the smooth endoplasmic reticulum (SER)?

Accepted Answer

Lipid synthesis and detoxification

Question 20

Which protein is responsible for severing microtubules during cytoskeletal remodeling?

Accepted Answer

Katanin

Cell Biology Study Guide: Membranes, Transport, Endomembrane System, and Cytoskeleton

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