Question 1

Which of the following molecules would most easily diffuse across a biological membrane’s lipid bilayer without facilitation?

Accepted Answer

O2

Question 2

Rank the following molecules from least to most permeable across a biological membrane by simple diffusion: Acetamide, Urea, Butyramide.

Accepted Answer

Acetamide → Butyramide → Urea

Question 3

Which of the following best describes passive membrane transport?

Accepted Answer

Movement of a substance down its concentration gradient

Question 4

What is the main difference between active and passive transport across a plasma membrane?

Accepted Answer

Active transport is ATP dependent, whereas passive transport does not require energy for movement across the plasma membrane.

Question 5

A transport protein that simultaneously transports two different molecules in different directions is called:

Accepted Answer

An antiporter

Question 6

Which option below best describes a transporter that requires ATP to move molecules A and B out of the cell?

Accepted Answer

An active antiporter

Question 7

The difference between simple and facilitated diffusion is that facilitated diffusion:

Accepted Answer

Requires a protein transporter

Question 8

Simple diffusion and facilitated diffusion across a membrane both:

Accepted Answer

Move molecules with their concentration gradient

Question 9

The rate of facilitated diffusion across a membrane is best described by which type of curve?

Accepted Answer

Hyperbolic (Michaelis-Menten)

Question 10

Which of the following is TRUE about the GLUT1 transporter in erythrocytes?

Accepted Answer

It is a facilitated uniporter

Question 11

The chloride shift in erythrocytes refers to:

Accepted Answer

The exchange of Cl– for bicarbonate ions in erythrocytes, causing HCO3– to leave the cell.

Question 12

Facilitated diffusion of charged ions across a biological membrane is:

Accepted Answer

Driven by a difference in the electrochemical gradient

Question 13

Which of the following statements about the sodium-potassium ATPase is FALSE?

Accepted Answer

The ATPase is phosphorylated by ATP to transport of Na+ into the cell.

Question 14

The calcium ATPase (SERCA) is an example of:

Accepted Answer

Primary active uniport

Question 15

ABC transporters are a part of a superfamily of transporters that have two nucleotide binding domains that bind ________, which is necessary for primary active transport.

Accepted Answer

ATP

Question 16

Which of the following is TRUE about the Na+-glucose symporter?

Accepted Answer

The energy stored in the Na+ gradient is harvested for the movement of glucose.

Question 17

Which of the following is NOT a true statement regarding exocytosis?

Accepted Answer

It forms intracellular vesicles from inward folding of the plasma membrane.

Question 18

Calculate the free energy change ($\Delta G_{transport}$) for the movement of Na+ into a cell when its concentration outside is 150 mM and its cytosolic concentration is 10 mM. Assume that $T = 20^\circ C$ and $\Delta \Psi = -50$ mV (inside negative). Use $R = 8.314$ J/(mol·K), $F = 96,485$ C/mol, and $z = +1$.

Accepted Answer

$-11.4$ KJ/mol

Question 19

Which process is responsible for the release of neurotransmitters from neurons?

Accepted Answer

Exocytosis

Biological Membranes and Transport: Mini-Textbook Study Guide

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