Q: Which equation is used to calculate the equilibrium potential for a single ion across a membrane?

The Nernst equation: $$E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the structure shown in the first image, and what is its primary function in the cell?

Accepted Answer

It is a double layer of phospholipids with embedded proteins, functioning as a selective barrier for substances entering and exiting the cell.

Question 2

Which type of membrane transport requires energy and moves substances against their concentration gradient?

Accepted Answer

Primary active transport

Question 3

A cell is observed to take in large particles by engulfing them with its membrane, forming vesicles. What is this process called?

Accepted Answer

Phagocytosis

Question 4

Which of the following statements about GLUT transporters is correct?

Accepted Answer

GLUT transporters are specific for naturally occurring 6-carbon sugars such as glucose, mannose, galactose, and fructose.

Question 5

Which equation is used to calculate the equilibrium potential for a single ion across a membrane?

Accepted Answer

The Nernst equation: $$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 6

A patient has a genetic mutation that reduces the number of sodium-potassium pumps in their cell membranes. What is the most likely effect on their resting membrane potential?

Accepted Answer

The resting membrane potential will become less negative due to decreased active transport of K+ and Na+.

Question 7

Which of the following best explains why the cell membrane is considered a 'selective barrier'?

Accepted Answer

It regulates the movement of substances based on their size, charge, and the presence of specific transport proteins.

Question 8

During epithelial glucose transport, which sequence correctly describes the movement of glucose from the intestinal lumen to the blood?

Accepted Answer

Glucose enters the epithelial cell via secondary active transport (SGLT), then exits to the blood via facilitated diffusion (GLUT).

Question 9

Which of the following is true regarding the resting membrane potential of most cells?

Accepted Answer

It is primarily determined by the permeability of the membrane to K+ ions.

Question 10

A researcher adds a competitive inhibitor to a solution containing a carrier protein and its substrate. What is the expected effect on the rate of substrate transport?

Accepted Answer

The rate of substrate transport will decrease due to competition for the binding site.

Question 11

Which of the following processes is an example of vesicular transport that moves substances out of the cell?

Accepted Answer

Exocytosis

Question 12

Which property of carrier-mediated transport describes the phenomenon where increasing substrate concentration no longer increases the rate of transport?

Accepted Answer

Saturation

Question 13

A cell is placed in a solution containing a high concentration of K+ outside and a low concentration inside. According to the Nernst equation, what will be the sign of the equilibrium potential for K+?

Accepted Answer

Positive

Question 14

Which of the following best describes paracellular transport in epithelial tissues?

Accepted Answer

Movement of substances between adjacent cells through tight junctions.

Question 15

Which of the following is NOT a feature of facilitated diffusion?

Accepted Answer

It requires ATP hydrolysis.

Question 16

A cell membrane is 40 times more permeable to K+ than to Na+. What is the most likely consequence for the resting membrane potential?

Accepted Answer

The resting membrane potential will be closer to the equilibrium potential of K+.

Question 17

Which of the following is a correct statement about electrical disequilibrium in cells?

Accepted Answer

It refers to the unequal distribution of charged ions across the cell membrane.

Question 18

Which of the following is true about the law of conservation of electrical charge?

Accepted Answer

The net amount of electrical charge produced in any process is zero.

Question 19

Which of the following best describes transcytosis in epithelial cells?

Accepted Answer

Transport of macromolecules across the cell by vesicular transport, involving endocytosis and exocytosis.

Cell Membrane Transport and Resting Membrane Potential: Study Notes for Anatomy & Physiology

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