Question 1

Which component of the cell membrane is primarily responsible for its semi-permeable nature?

Accepted Answer

Phospholipid bilayer with hydrophobic tails and hydrophilic heads

Question 2

A patient is given a drug that blocks the function of the Na+/K+ pump. What immediate effect would this have on the cell?

Accepted Answer

The cell would accumulate Na+ ions inside and lose K+ ions, disrupting membrane potential

Question 3

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient via transport proteins without energy input

Question 4

Which equation correctly represents the rate of diffusion according to Fick's Law?

Accepted Answer

$$J = D \frac{(C_1$ - C_2$)}{d}$$

Question 5

Which of the following is an example of coupled transport in cell membranes?

Accepted Answer

Na+/glucose symporter

Question 6

A virus enters a host cell by binding to a receptor and being engulfed in a vesicle. Which process is this?

Accepted Answer

Endocytosis

Question 7

Which of the following statements about antiporters is correct?

Accepted Answer

They transport two molecules in opposite directions across the membrane

Question 8

Which factor would NOT increase the rate of diffusion across a cell membrane?

Accepted Answer

Decreasing the surface area of the membrane

Question 9

Which of the following is a characteristic of transport proteins involved in active transport?

Accepted Answer

They require energy input, often from ATP hydrolysis

Question 10

A cell uses exocytosis to release neurotransmitters into the synaptic cleft. Which step is essential for this process?

Accepted Answer

Fusion of the vesicle membrane with the plasma membrane

Question 11

Which of the following best describes a uniporter?

Accepted Answer

A protein that transports a single type of molecule across the membrane

Question 12

During virotherapy, viruses are used to deliver therapeutic genes into cells. Which membrane transport process is most likely involved in the entry of these viruses?

Accepted Answer

Endocytosis

Question 13

Which of the following molecules is LEAST likely to cross the cell membrane by simple diffusion?

Accepted Answer

Glucose

Question 14

A cell is placed in a solution with a higher concentration of solutes than inside the cell. What will happen to the cell?

Accepted Answer

Water will move out of the cell, causing it to shrink

Question 15

Which process requires the direct hydrolysis of ATP?

Accepted Answer

Active transport via Na+/K+ ATPase

Question 16

Which of the following is true about the Na+/glucose symporter?

Accepted Answer

It uses the energy of Na+ moving down its gradient to transport glucose against its gradient

Question 17

Which of the following is NOT a function of membrane transport proteins?

Accepted Answer

Acting as enzymes to catalyze chemical reactions

Question 18

A researcher observes that a cell is able to import glucose only when Na+ is present in the extracellular fluid. Which type of transport is most likely responsible?

Accepted Answer

Coupled transport (symport)

Question 19

Which of the following best explains why ions cannot easily cross the phospholipid bilayer by simple diffusion?

Accepted Answer

Ions are hydrophilic and repelled by the hydrophobic core of the bilayer

Question 20

Which of the following is a real-world example of exocytosis?

Accepted Answer

Release of insulin from pancreatic beta cells

Membrane Transport: Key Concepts and Mechanisms

Guida di studio - Domande di pratica

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