Q: Which equation best represents the energy requirement for primary active transport?

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

Q: Which equation best represents the resting membrane potential (RMP) in most cells?

$$ \text{RMP} \approx -80 \ \text{mV} $$

Question 1

Which of the following best describes the difference between primary and secondary active transport?

Accepted Answer

Primary active transport uses energy from ATP hydrolysis directly, while secondary active transport uses energy indirectly from ionic gradients created by primary active transport.

Question 2

A cell is observed to transport glucose into its cytoplasm by coupling it with sodium ions moving down their concentration gradient. Which type of membrane transport is this?

Accepted Answer

Secondary active transport using a symporter

Question 3

The Na	extsuperscript{+}-K	extsuperscript{+} pump is crucial for maintaining cellular homeostasis. What is the net movement of ions per ATP hydrolyzed?

Accepted Answer

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

Question 4

Which equation best represents the energy requirement for primary active transport?

Accepted Answer

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

Question 5

Which of the following is NOT a reason why a solute would require active transport to cross the plasma membrane?

Accepted Answer

The solute is able to move down its concentration gradient.

Question 6

A cell uses an antiporter to move Na	extsuperscript{+} out and K	extsuperscript{+} in. What type of transport is this and what is its significance?

Accepted Answer

Primary active transport; it maintains electrochemical gradients essential for muscle and nerve function.

Question 7

Which of the following best explains why the inside of a cell is more negative than the outside at rest?

Accepted Answer

K	extsuperscript{+} leaks out of the cell down its concentration gradient, while negatively charged proteins remain inside.

Question 8

Which process is described as 'cell eating' and involves the formation of pseudopods?

Accepted Answer

Phagocytosis

Question 9

A white blood cell engulfs a bacterium by extending its membrane around the particle. What is the name of the vesicle formed and what happens next?

Accepted Answer

Phagosome; it fuses with a lysosome for digestion.

Question 10

Which type of endocytosis is nonspecific and is the main way nutrients are absorbed in the small intestine?

Accepted Answer

Pinocytosis

Question 11

Which of the following is TRUE about receptor-mediated endocytosis?

Accepted Answer

It is highly selective and involves clathrin-coated pits.

Question 12

Which equation best represents the resting membrane potential (RMP) in most cells?

Accepted Answer

$$ 	ext{RMP} \approx -80 \ 	ext{mV} $$

Question 13

Which of the following is a function of cell adhesion molecules (CAMs)?

Accepted Answer

They anchor cells to the extracellular matrix and assist in cell movement.

Question 14

What is the role of G protein-linked receptors in chemical signaling?

Accepted Answer

They activate G proteins, which can affect ion channels, enzymes, or release second messengers.

Question 15

Which of the following best describes the process of exocytosis?

Accepted Answer

Materials are expelled from the cell in secretory vesicles that fuse with the plasma membrane.

Question 16

A cell is exposed to a toxin that blocks ATP synthesis. Which transport process would be most directly affected?

Accepted Answer

Primary active transport

Question 17

Which of the following statements about membrane potential is correct?

Accepted Answer

Voltage occurs only at the membrane surface; the rest of the cell and extracellular fluid are neutral.

Question 18

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 19

Which equation best represents the movement of ions by the Na	extsuperscript{+}-K	extsuperscript{+} pump?

Accepted Answer

$$ 3 \ 	ext{Na}^+_{	ext{in}} + 2 \ 	ext{K}^+_{	ext{out}} + 	ext{ATP} ightarrow 3 \ 	ext{Na}^+_{	ext{out}} + 2 \ 	ext{K}^+_{	ext{in}} + 	ext{ADP} + 	ext{P}_i $$

Question 20

Which of the following would most likely increase the resting membrane potential from -80 mV to -70 mV?

Accepted Answer

Increased permeability of the membrane to Na	extsuperscript{+}

Active Membrane Transport: Mechanisms and Physiological Roles 3B

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