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 of the cell membrane as shown in the image?

Accepted Answer

A double layer of phospholipids with embedded proteins and carbohydrates.

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 placed in a solution containing a high concentration of glucose. Which transport mechanism will allow glucose to enter the cell most efficiently if the cell membrane is impermeable to glucose?

Accepted Answer

Facilitated diffusion via GLUT transporters

Question 4

Which of the following statements about specificity, competition, and saturation in carrier-mediated transport is correct?

Accepted Answer

Transporters have a maximum rate when all are occupied, known as saturation.

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 defect in GLUT transporters. Which of the following sugars would most likely have impaired cellular uptake?

Accepted Answer

D-Glucose

Question 7

Which of the following is NOT a type of vesicular transport?

Accepted Answer

Facilitated diffusion

Question 8

During epithelial glucose transport, which membrane is responsible for the initial uptake of glucose from the lumen?

Accepted Answer

Apical membrane

Question 9

Which of the following best explains why the resting membrane potential of most cells is closer to the equilibrium potential of potassium ($E_K$) than sodium ($E_{Na}$)?

Accepted Answer

The cell membrane is more permeable to potassium ions than sodium ions.

Question 10

Which of the following scenarios best illustrates competition in carrier-mediated transport?

Accepted Answer

Galactose and glucose both compete for the same GLUT transporter.

Question 11

Which process is most likely to be used by a cell to secrete large hydrophilic molecules such as hormones?

Accepted Answer

Exocytosis

Question 12

A researcher measures the rate of glucose transport into a cell and finds that increasing glucose concentration beyond a certain point does not increase the rate. What is the most likely explanation?

Accepted Answer

The transporters are saturated.

Question 13

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

Accepted Answer

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

Question 14

Which of the following is a correct statement about tight junctions in epithelial cells?

Accepted Answer

They restrict movement of substances between cells.

Question 15

Which of the following is an example of transcytosis in epithelial transport?

Accepted Answer

A molecule is endocytosed on one side of the cell and exocytosed on the other side.

Question 16

Which of the following ions is most abundant inside the cell and contributes to the negative resting membrane potential?

Accepted Answer

Potassium ($K^+$)

Question 17

Which of the following best describes the role of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It actively transports $3$ $Na^+$ out and $2$ $K^+$ in, maintaining concentration gradients.

Question 18

Which of the following is a property of excitable cells such as neurons and muscle cells?

Accepted Answer

They have a resting membrane potential that can change rapidly in response to stimuli.

Question 19

Which of the following is true about electrical disequilibrium in cells?

Accepted Answer

It is created by the uneven distribution of ions across the cell membrane.

Question 20

A cell is exposed to a toxin that blocks all ATP production. Which transport processes will be immediately affected?

Accepted Answer

Primary active transport and vesicular transport

Cell Membrane Transport and Resting Membrane Potential: Study Notes for Anatomy & Physiology CM4

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