Q: Which of the following equations best represents the energy required for primary active transport?

$$ \text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{energy} $$

Question 1

Which of the following best describes primary active transport across the plasma membrane?

Accepted Answer

It uses energy directly from ATP hydrolysis to move solutes against their concentration gradient.

Question 2

The sodium-potassium pump (Na	extsuperscript{+}-K	extsuperscript{+} ATPase) typically moves how many sodium and potassium ions per cycle?

Accepted Answer

3 Na	extsuperscript{+} out, 2 K	extsuperscript{+} in

Question 3

Which of the following is a direct inhibitor of the Na	extsuperscript{+}-K	extsuperscript{+} pump and is used as a cardiac drug?

Accepted Answer

Ouabain (foxglove)

Question 4

Secondary active transport relies on which of the following to move solutes against their concentration gradient?

Accepted Answer

Energy stored in ionic gradients created by primary active transport

Question 5

Which type of vesicular transport is responsible for the uptake of large particles such as bacteria by white blood cells?

Accepted Answer

Phagocytosis

Question 6

A cell in the small intestine absorbs nutrients from the lumen by engulfing extracellular fluid and dissolved solutes. Which process is primarily responsible for this?

Accepted Answer

Pinocytosis

Question 7

Which of the following statements about membrane potential is correct?

Accepted Answer

The resting membrane potential is typically negative, with the inside of the cell more negative than the outside.

Question 8

Which ion is the primary determinant of the resting membrane potential in most cells?

Accepted Answer

K	extsuperscript{+}

Question 9

A mutation causes a cell to lose its ability to form clathrin-coated pits. Which process would be most directly affected?

Accepted Answer

Receptor-mediated endocytosis

Question 10

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

Accepted Answer

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

Question 11

Which of the following equations best represents the energy required for primary active transport?

Accepted Answer

$$ 	ext{ATP} ightarrow 	ext{ADP} + 	ext{P}_i + 	ext{energy} $$

Question 12

A patient is exposed to black widow spider venom, which causes massive and uncontrolled exocytosis of acetylcholine at the neuromuscular junction. What is the most likely physiological effect?

Accepted Answer

Muscle spasms and convulsions due to excessive neurotransmitter release

Question 13

Which of the following is TRUE regarding the concentration gradients of Na	extsuperscript{+} and K	extsuperscript{+} across the plasma membrane?

Accepted Answer

Na	extsuperscript{+} concentration is higher outside the cell, K	extsuperscript{+} concentration is higher inside the cell.

Question 14

Which process is most likely to be used by a cell to secrete hormones into the bloodstream?

Accepted Answer

Exocytosis

Question 15

A cell is observed to transport glucose into its cytoplasm by coupling it with Na	extsuperscript{+} influx. Which type of transporter is most likely involved?

Accepted Answer

Symporter

Question 16

Which of the following best describes the role of K	extsuperscript{+} leakage channels in establishing the resting membrane potential?

Accepted Answer

They allow K	extsuperscript{+} to diffuse out of the cell, making the inside more negative.

Question 17

Which of the following is a multi-step process involving both endocytosis and exocytosis to move substances across a cell?

Accepted Answer

Transcytosis

Question 18

A cell is exposed to a toxin that blocks the formation of v-SNARE proteins. Which cellular process would be most directly impaired?

Accepted Answer

Exocytosis

Question 19

Which of the following best explains why the resting membrane potential is typically negative?

Accepted Answer

Negatively charged proteins are trapped inside the cell and K	extsuperscript{+} diffuses out, making the inside more negative.

Active Membrane Transport and Membrane Potential in Cells

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