Question 1

Which of the following best describes the difference between homeostasis and equilibrium in the context of body fluid compartments?

Accepted Answer

Homeostasis refers to the maintenance of a constant internal environment, while equilibrium means all compartments have equal concentrations of solutes.

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome for the cell?

Accepted Answer

The cell will swell and may burst due to water entering the cell by osmosis.

Question 3

Which of the following is an example of primary active transport?

Accepted Answer

The sodium-potassium pump ($ \mathrm{Na^+/K^+} $ ATPase) moving $ \mathrm{Na^+} $ out and $ \mathrm{K^+} $ into the cell using ATP.

Question 4

According to Fick's Law of Diffusion, which of the following changes would increase the rate of diffusion across a membrane?

Accepted Answer

Increasing the surface area of the membrane.

Question 5

Which equation correctly represents Fick's Law of Diffusion?

Accepted Answer

$ J = -D \frac{\Delta C}{\Delta x} $

Question 6

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient via a membrane protein, without energy input.

Question 7

A patient is given an intravenous solution that is hypertonic relative to their blood plasma. What will happen to their red blood cells?

Accepted Answer

The cells will shrink as water leaves the cells.

Question 8

Which of the following is a characteristic of secondary active transport?

Accepted Answer

It uses the energy stored in the concentration gradient of one molecule to drive the movement of another molecule.

Question 9

Which of the following best describes the function of the sodium-potassium pump ($ \mathrm{Na^+/K^+} $ ATPase)?

Accepted Answer

It moves 3 $ \mathrm{Na^+} $ ions out of the cell and 2 $ \mathrm{K^+} $ ions into the cell per ATP hydrolyzed.

Question 10

Which of the following is true regarding the resting membrane potential of a typical neuron?

Accepted Answer

It is approximately $ -70 \ \mathrm{mV} $, with the inside of the cell negative relative to the outside.

Question 11

Which of the following best describes the process of exocytosis?

Accepted Answer

Vesicles fuse with the plasma membrane to release their contents outside the cell.

Question 12

A cell is placed in an isotonic solution. What will happen to the cell's volume?

Accepted Answer

The cell's volume will remain unchanged.

Question 13

Which of the following is an example of a symport secondary active transporter?

Accepted Answer

Sodium-glucose cotransporter (SGLT)

Question 14

Which of the following factors would decrease the rate of diffusion across a cell membrane according to Fick's Law?

Accepted Answer

Increasing the thickness of the membrane ($ \Delta x $)

Question 15

Which of the following best describes the Nernst equation and its physiological significance?

Accepted Answer

It calculates the equilibrium potential for a specific ion based on its concentration gradient across the membrane.

Question 16

Which of the following is NOT a characteristic of carrier proteins involved in facilitated diffusion?

Accepted Answer

They can transport molecules against their concentration gradient using ATP.

Question 17

A neuron rapidly depolarizes during an action potential. Which type of membrane protein is primarily responsible for this event?

Accepted Answer

Voltage-gated sodium channels

Question 18

Which of the following best describes the process of endocytosis?

Accepted Answer

The cell membrane engulfs extracellular material, forming a vesicle that brings substances into the cell.

Question 19

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

Accepted Answer

The cell membrane is more permeable to $ \mathrm{K^+} $ than $ \mathrm{Na^+} $, allowing more $ \mathrm{K^+} $ to leave the cell.

Question 20

Which of the following is an example of an antiport secondary active transporter?

Accepted Answer

Sodium-calcium exchanger ($ \mathrm{Na^+/Ca^{2+}} $ antiporter)

Membrane Transport and Homeostasis: Study Notes for Anatomy & Physiology

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