Q: Which of the following equations best represents the selective permeability of the plasma membrane to ions, considering the presence of transport proteins?

$J = P \times (C_{out} - C_{in})$

Question 1

Which of the following best describes the amphipathic nature of phospholipids in the plasma membrane?

Accepted Answer

They have both hydrophilic and hydrophobic regions.

Question 2

A patient is diagnosed with a genetic disorder that affects the formation of desmosomes. Which tissue would most likely be affected, and what symptom might result?

Accepted Answer

Epithelial tissue; increased risk of skin blistering due to cells tearing apart.

Question 3

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Storing genetic information.

Question 4

A researcher observes that certain cells are able to communicate rapidly by passing ions directly from one cell to another. Which type of cell junction is responsible for this?

Accepted Answer

Gap junctions

Question 5

Which component of the plasma membrane is primarily responsible for cell-to-cell recognition and immune system identification of 'self' versus 'nonself'?

Accepted Answer

Glycocalyx

Question 6

A hormone is released into the bloodstream and binds to a receptor on a distant target cell, initiating a cellular response. Which type of signaling is this an example of?

Accepted Answer

Endocrine (hormonal) signaling

Question 7

Which of the following best explains why steroid hormones can bind to intracellular receptors?

Accepted Answer

Steroid hormones are hydrophobic and can diffuse through the phospholipid bilayer.

Question 8

Which of the following equations best represents the selective permeability of the plasma membrane to ions, considering the presence of transport proteins?

Accepted Answer

$J = P 	imes (C_{out} - C_{in})$

Question 9

A mutation causes the glycocalyx of certain cells to change rapidly, making them unrecognizable to the immune system. What is a likely consequence of this mutation?

Accepted Answer

The mutated cells may evade immune detection and proliferate uncontrollably.

Question 10

Which of the following best describes the sequence of events in cell signaling?

Accepted Answer

Reception → Transduction → Response

Question 11

A scientist is studying a membrane protein that is loosely attached to the surface of the plasma membrane and functions as an enzyme. Which type of protein is this?

Accepted Answer

Peripheral protein

Question 12

Which of the following best explains why tight junctions are important in the lining of the stomach?

Accepted Answer

They prevent gastric fluids from leaking between epithelial cells.

Question 13

Which of the following is a real-life example of the function of gap junctions in the human body?

Accepted Answer

Coordinated contraction of cardiac muscle cells.

Question 14

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

Accepted Answer

It stabilizes membrane fluidity across temperature changes.

Question 15

A cell is exposed to a toxin that inhibits the function of its transport proteins. Which of the following is a likely consequence?

Accepted Answer

The cell will be unable to regulate the movement of specific ions and molecules across its membrane.

Question 16

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

Accepted Answer

It is composed of a dynamic arrangement of lipids and proteins that can move laterally within the layer.

Question 17

Which of the following best describes the function of the extracellular matrix (ECM)?

Accepted Answer

It acts as a glue to hold cells together.

Question 18

A cell is unable to anchor its cytoskeleton to the plasma membrane. Which function is most likely impaired?

Accepted Answer

Maintaining cell shape and stabilizing the location of certain membrane proteins.

Question 19

Which of the following best describes the role of membrane proteins in enzymatic activity?

Accepted Answer

They catalyze sequential steps of metabolic pathways at the membrane.

Question 20

A cell is exposed to a chemical that disrupts the function of cadherins. Which type of cell junction would be most affected?

Accepted Answer

Desmosomes

Cell Membranes, Junctions, and Signaling: Structure and Function in Anatomy & Physiology

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