Q: Which equation best represents the amphipathic nature of a phospholipid molecule?

$$\text{Phospholipid} = \text{Hydrophilic head} + \text{Hydrophobic tails}$$

Question 1

Which of the following is a major structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have a true nucleus surrounded by a double membrane, while prokaryotic cells lack a nucleus.

Question 2

According to the fluid mosaic model, which statement best describes the behavior of membrane proteins?

Accepted Answer

Membrane proteins can drift laterally within the lipid bilayer, contributing to membrane fluidity.

Question 3

Which component of the plasma membrane is primarily responsible for its selective permeability?

Accepted Answer

Phospholipid bilayer

Question 4

A scientist uses fluorescence recovery after photobleaching (FRAP) to study membrane dynamics. What does a rapid recovery of fluorescence indicate about the membrane?

Accepted Answer

The membrane is fluid and proteins/lipids can move laterally.

Question 5

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

Cholesterol stabilizes membrane fluidity by reducing fluidity at moderate temperatures and preventing solidification at low temperatures.

Question 6

Which equation best represents the amphipathic nature of a phospholipid molecule?

Accepted Answer

$$	ext{Phospholipid} = 	ext{Hydrophilic head} + 	ext{Hydrophobic tails}$$

Question 7

A mutation causes a cell to produce only saturated fatty acids in its membrane phospholipids. What is the most likely effect on the cell membrane at low temperatures?

Accepted Answer

The membrane will become more rigid and may solidify.

Question 8

Which of the following is a function of glycoproteins in the plasma membrane?

Accepted Answer

Cell-cell recognition and signaling

Question 9

Which process is illustrated by the movement of a neutrophil chasing a bacterium, as shown in the provided image?

Accepted Answer

Cellular communication and dynamic membrane remodeling

Question 10

Which of the following best describes the orientation of phospholipids in a biological membrane?

Accepted Answer

Hydrophilic heads face both the extracellular and cytosolic environments, while hydrophobic tails face inward.

Question 11

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

Accepted Answer

ATP synthesis in the cytosol

Question 12

A patient is resistant to HIV infection due to a mutation in a membrane protein. Which protein is most likely mutated?

Accepted Answer

CCR5 co-receptor

Question 13

Which of the following best explains the experimental evidence for the lateral movement of membrane proteins?

Accepted Answer

Hybrid cells show rapid intermixing of mouse and human membrane proteins after fusion.

Question 14

Which of the following equations represents the relationship between membrane fluidity and temperature in the presence of cholesterol?

Accepted Answer

$$	ext{Fluidity} \downarrow at $$moderate temperatures, $$	ext{Fluidity} \uparrow at $$low temperatures$

Question 15

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

Accepted Answer

It provides a net negative charge and is involved in anchoring peripheral proteins.

Question 16

Which of the following is a real-world example of membrane protein function in human health?

Accepted Answer

ACE-2 receptor mediates viral entry for SARS-CoV-2.

Question 17

Which of the following best describes the assembly of membrane asymmetry during biosynthesis?

Accepted Answer

Membrane asymmetry begins in the endoplasmic reticulum and is maintained during vesicle trafficking.

Question 18

Which of the following is a correct application of the fluid mosaic model to explain membrane protein function?

Accepted Answer

Integral proteins are embedded in the bilayer and can move laterally, allowing dynamic cellular responses.

Question 19

A cell is exposed to a toxin that disrupts the attachment of peripheral membrane proteins. Which cellular process is most likely to be affected?

Accepted Answer

Cell signaling and cytoskeletal attachment

Cell Structure and Membrane Dynamics: General Biology Study Notes

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