Q: Which of the following units would be most appropriate for measuring the rate of diffusion of glucose into a cell?

$$\text{mol} \cdot \text{L}^{-1} \cdot \text{s}^{-1}$$

Question 1

Which of the following units would be most appropriate for measuring the rate of diffusion of glucose into a cell?

Accepted Answer

$$	ext{mol} \cdot 	ext{L}^{-1} \cdot 	ext{s}^{-1}$$

Question 2

Based on Graph #1, which shows intracellular glucose concentration leveling off over time, what is the most likely explanation for this plateau?

Accepted Answer

The cell has reached equilibrium with the extracellular glucose concentration.

Question 3

Graph #2 shows a linear increase in the rate of glucose diffusion with increasing extracellular glucose concentration. What does this suggest about the transport mechanism?

Accepted Answer

Glucose is moving by simple diffusion.

Question 4

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement down a concentration gradient through a protein transporter, without energy input.

Question 5

Which transport method is characterized by specificity, competition, and saturation?

Accepted Answer

Facilitated diffusion

Question 6

A cell uses ATP to move sodium ions out against their concentration gradient. Which transport method is this?

Accepted Answer

Primary active transport

Question 7

Which of the following factors would NOT affect the rate of simple diffusion across a membrane?

Accepted Answer

Presence of a specific protein transporter

Question 8

Which of the following is an example of secondary active transport?

Accepted Answer

Glucose uptake into intestinal cells using the sodium gradient

Question 9

If a transport process exhibits saturation, what does this imply about the mechanism?

Accepted Answer

It involves a finite number of protein transporters.

Question 10

Which equation best represents Fick's Law of Diffusion?

Accepted Answer

$$J = -D \frac{dC}{dx}$$

Question 11

A patient is given a drug that blocks all protein transporters in a cell membrane. Which process would be LEAST affected?

Accepted Answer

Simple diffusion of oxygen

Question 12

Which of the following statements about primary and secondary active transport is correct?

Accepted Answer

Primary active transport uses ATP directly, while secondary active transport uses the energy stored in ion gradients.

Question 13

A cell is placed in a solution with a high concentration of glucose. Over time, the rate of glucose entry plateaus despite increasing extracellular glucose. What is the most likely explanation?

Accepted Answer

The glucose transporters are saturated.

Question 14

Which of the following is NOT a characteristic of simple diffusion?

Accepted Answer

Exhibits saturation at high substrate concentrations

Question 15

Which of the following best describes competition in facilitated diffusion?

Accepted Answer

Two similar molecules compete for the same transporter protein.

Transport Mechanisms and Diffusion in Cells – Guided Study

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