Q: Which of the following best describes the main function of the Na\textsuperscript{+}-K\textsuperscript{+} ATPase pump in excitable cells such as neurons and muscle fibers?

It actively transports Na\textsuperscript{+} out of the cell and K\textsuperscript{+} into the cell, maintaining electrochemical gradients essential for nerve and muscle function.

Q: Which of the following best explains why the inside of a resting cell membrane is negatively charged relative to the outside?

K\textsuperscript{+} diffuses out of the cell through leakage channels, leaving behind negatively charged proteins that cannot cross the membrane.

Q: Which equation correctly represents the stoichiometry of the Na\textsuperscript{+}-K\textsuperscript{+} pump per ATP hydrolyzed?

$$3\ \mathrm{Na}^{+}\ \text{out},\ 2\ \mathrm{K}^{+}\ \text{in}$$

Question 1

Which of the following best describes the main function of the Na	extsuperscript{+}-K	extsuperscript{+} ATPase pump in excitable cells such as neurons and muscle fibers?

Accepted Answer

It actively transports Na	extsuperscript{+} out of the cell and K	extsuperscript{+} into the cell, maintaining electrochemical gradients essential for nerve and muscle function.

Question 2

A cell is observed to take in large solid particles by extending its plasma membrane around them, forming vesicles. Which process is being described?

Accepted Answer

Phagocytosis

Question 3

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

Accepted Answer

It relies on ion gradients established by primary active transport to move other substances against their gradients.

Question 4

During the process of exocytosis, which of the following events occurs LAST?

Accepted Answer

The vesicle releases its contents to the exterior of the cell.

Question 5

A patient has a mutation that causes their Na	extsuperscript{+}-K	extsuperscript{+} ATPase pumps to stop functioning. Which of the following would most likely occur as a result?

Accepted Answer

The resting membrane potential would become less negative, impairing nerve and muscle function.

Question 6

Which of the following best explains why the inside of a resting cell membrane is negatively charged relative to the outside?

Accepted Answer

K	extsuperscript{+} diffuses out of the cell through leakage channels, leaving behind negatively charged proteins that cannot cross the membrane.

Question 7

Which of the following is NOT a function of cell adhesion molecules (CAMs)?

Accepted Answer

Facilitating the synthesis of ATP from ADP

Question 8

A cell in the small intestine absorbs nutrients by engulfing droplets of extracellular fluid. Which process is responsible for this?

Accepted Answer

Pinocytosis

Question 9

Which of the following best describes the role of G protein-linked receptors in chemical signaling?

Accepted Answer

They activate G proteins, which then trigger the production of second messengers inside the cell.

Question 10

Which equation correctly represents the stoichiometry of the Na	extsuperscript{+}-K	extsuperscript{+} pump per ATP hydrolyzed?

Accepted Answer

$$3\ \mathrm{Na}^{+}\ 	ext{out},\ 2\ \mathrm{K}^{+}\ 	ext{in}$$

Question 11

Which of the following is a key difference between primary and secondary active transport?

Accepted Answer

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

Question 12

A cell is exposed to a toxin that blocks clathrin-coated pit formation. Which process would be most directly affected?

Accepted Answer

Receptor-mediated endocytosis

Question 13

Which of the following best describes the voltage across a typical resting cell membrane?

Accepted Answer

$$-70\ \mathrm{mV}$$, with the inside more negative than the outside

Question 14

Which of the following is TRUE regarding vesicular transport?

Accepted Answer

It transports large particles, macromolecules, and fluids via membranous sacs called vesicles.

Question 15

Which of the following scenarios best illustrates the concept of transcytosis?

Accepted Answer

A molecule is taken into a cell by endocytosis, transported across the cell, and released on the opposite side by exocytosis.

Question 16

Which of the following is a real-life example of receptor-mediated endocytosis?

Accepted Answer

Uptake of low-density lipoproteins (LDL) by liver cells

Question 17

Which of the following best explains why the Na	extsuperscript{+}-K	extsuperscript{+} pump is considered an antiporter?

Accepted Answer

It moves Na	extsuperscript{+} and K	extsuperscript{+} in opposite directions across the membrane.

Question 18

A cell is exposed to a drug that increases the permeability of its plasma membrane to Na	extsuperscript{+}. What effect would this have on the resting membrane potential?

Accepted Answer

The resting membrane potential would become less negative (closer to zero).

Question 19

Which of the following best describes the sequence of events in G protein-coupled receptor signaling?

Accepted Answer

Ligand binds receptor → G protein activated → Effector enzyme activated → Second messenger produced → Cellular response

Active Membrane Transport and Cell-Environment Interactions: Study Notes for Anatomy & Physiology

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