Question 1

Which of the following statements best describes the difference between simple diffusion and facilitated diffusion across a biological membrane?

Accepted Answer

Facilitated diffusion requires specific transport proteins, while simple diffusion does not.

Question 2

A red blood cell is placed in a solution with a higher concentration of NaCl than inside the cell. What will happen to the water movement, and which process is responsible?

Accepted Answer

Water will move out of the cell by osmosis.

Question 3

Which of the following is an example of antiport transport in erythrocytes?

Accepted Answer

Anion exchange protein transporting Cl$$^-$$ and HCO$$_3^- in $$opposite directions

Question 4

The Na$$^+/K$^+$$ pump is an example of which type of membrane transport?

Accepted Answer

Primary active transport

Question 5

Which equation would you use to calculate the free energy change ($$\Delta G) $$for the transport of an uncharged solute across a membrane?

Accepted Answer

$$\Delta G = RT \ln \left( \frac{[S]_{inside}}{[S]_{outside}} \right)$$

Question 6

Which of the following best explains why ions such as Na$$^+$$ and K$$^+$$ cannot cross the plasma membrane by simple diffusion?

Accepted Answer

They are repelled by the hydrophobic core of the membrane.

Question 7

A cell uses a symporter to import glucose along with Na$$^+. $$What is the source of energy for this transport?

Accepted Answer

The Na$$^+$$ gradient established by the Na$$^+/K$^+$$ pump

Question 8

Which of the following is true about aquaporins?

Accepted Answer

They are channel proteins that facilitate rapid water movement.

Question 9

In Halobacterium, what is the immediate effect of light absorption by bacteriorhodopsin?

Accepted Answer

Protons are pumped across the membrane.

Question 10

Which of the following statements about the partition coefficient ($$K_{PC}) is $$correct?

Accepted Answer

A high $$K_{PC}$$ means the compound is more soluble in oil than in water.

Question 11

Which of the following best describes the direction of net movement for a solute during simple diffusion?

Accepted Answer

From high concentration to low concentration

Question 12

Which of the following is a property of facilitated diffusion but NOT of simple diffusion?

Accepted Answer

Saturation kinetics

Question 13

A mutation in the GLUT1 transporter in erythrocytes would most directly affect which process?

Accepted Answer

Glucose uptake by facilitated diffusion

Question 14

Which of the following is a correct statement about the energetics of transport for charged solutes?

Accepted Answer

The membrane potential must be included in the calculation of $$\Delta G.$$

Question 15

Which of the following best describes the function of the Na$$^+/K$^+$$ pump in animal cells?

Accepted Answer

It moves Na$$^+$$ out and K$$^+ in$$, both against their concentration gradients.

Question 16

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

Accepted Answer

Na$$^+/$$glucose symporter

Question 17

Which of the following is NOT a property of active transport?

Accepted Answer

Does not require a membrane protein

Question 18

A cell is found to have a defective anion exchange protein. Which process would be most directly affected?

Accepted Answer

Exchange of Cl$$^-$$ and HCO$$_3^-$$ across the membrane

Question 19

Which of the following best describes the role of carrier proteins in facilitated diffusion?

Accepted Answer

They undergo conformational changes to move solutes across the membrane.

Question 20

Which of the following is a correct formula for the free energy change ($$\Delta G) $$for the inward transport of a charged solute?

Accepted Answer

$$\Delta G = RT \ln \left( \frac{[S]_{inside}}{[S]_{outside}} \right) + zF V_m$$

Transport Across Membranes: Mechanisms and Energetics

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