Q: A cell is actively transporting sodium ions out and potassium ions in, both against their concentration gradients. Which equation best represents the stoichiometry of the Na+-K+ ATPase pump?

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

Question 1

Which of the following best describes the function of the plasma (cell) membrane in human cells?

Accepted Answer

It serves as a flexible boundary that controls what enters and leaves the cell, maintaining a dynamic role in cellular activity.

Question 2

A red blood cell is placed in a hypertonic solution. What is the most likely outcome, and which process is responsible?

Accepted Answer

The cell will shrink (crenate) as water leaves the cell by osmosis.

Question 3

Which of the following best explains why the plasma membrane is described as a 'fluid mosaic'?

Accepted Answer

It consists of many different pieces, including lipids and proteins, that move and shift within the membrane.

Question 4

Which of the following molecules can most easily diffuse through the plasma membrane by simple diffusion?

Accepted Answer

Oxygen

Question 5

A cell is placed in a solution with a lower osmolarity than its cytoplasm. What will happen to the cell, and what is this solution called?

Accepted Answer

The cell will swell; the solution is hypotonic.

Question 6

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

It increases membrane stability by fitting between phospholipids.

Question 7

Which type of membrane protein is most likely to function as a receptor for a hormone?

Accepted Answer

Integral protein

Question 8

A patient is given an intravenous solution that is hypotonic relative to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

The cells will gain water and may burst (lyse).

Question 9

Which of the following best explains why facilitated diffusion is considered a passive process?

Accepted Answer

It moves molecules down their concentration gradient without using cellular energy.

Question 10

Which of the following is a function of peripheral proteins in the plasma membrane?

Accepted Answer

Acting as enzymes or providing structural support to the membrane

Question 11

A cell is actively transporting sodium ions out and potassium ions in, both against their concentration gradients. Which equation best represents the stoichiometry of the Na+-K+ ATPase pump?

Accepted Answer

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

Question 12

Which of the following best describes the process of phagocytosis?

Accepted Answer

The cell engulfs large particles by extending pseudopods around them and enclosing them in a vesicle.

Question 13

Which of the following statements about the resting membrane potential (RMP) is correct?

Accepted Answer

The RMP is established mainly by the movement of potassium ions out of the cell through leakage channels.

Question 14

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

Accepted Answer

Potassium ions diffuse out of the cell, leaving behind negatively charged proteins.

Question 15

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 ionic gradients.

Question 16

Which of the following best describes the function of gap junctions in cardiac muscle cells?

Accepted Answer

They allow the rapid passage of ions and small molecules, enabling electrical signals to spread quickly.

Question 17

A cell is exposed to a toxin that blocks all carrier-mediated facilitated diffusion. Which of the following would most likely be impaired?

Accepted Answer

Glucose uptake into the cell

Question 18

Which of the following best describes the role of G protein-coupled receptors (GPCRs) in cell signaling?

Accepted Answer

They bind ligands and activate G proteins, which then trigger intracellular signaling cascades.

Question 19

During which phase of the cell cycle is DNA replicated in preparation for cell division?

Accepted Answer

S phase

Question 20

Which of the following best describes the function of lysosomes in the cell?

Accepted Answer

They contain digestive enzymes for breakdown of cellular debris.

Chapter 3: Cells – The Living Units (Anatomy & Physiology Study Notes)

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