Question 1

Which of the following is NOT a primary function of biological membranes?

Accepted Answer

Serving as the main site of ATP synthesis

Question 2

According to the fluid mosaic model, which statement best describes the arrangement of proteins and lipids in the membrane?

Accepted Answer

Proteins are embedded within a fluid lipid bilayer, allowing lateral movement

Question 3

Which class of membrane lipids is most abundant in biological membranes?

Accepted Answer

Phospholipids

Question 4

What is the effect of increasing fatty acid chain length on membrane fluidity and transition temperature ($T_m$)?

Accepted Answer

Decreases fluidity and increases $T_m$

Question 5

Which of the following statements about cholesterol in animal cell membranes is TRUE?

Accepted Answer

Cholesterol acts as a fluidity buffer, decreasing fluidity and increasing $T_m$

Question 6

Which type of membrane protein can be separated from the membrane by changes in pH or ionic strength?

Accepted Answer

Peripheral membrane proteins

Question 7

A mutation causes a cell to produce only saturated fatty acids in its membrane phospholipids. What is the most likely effect on membrane fluidity and $T_m$?

Accepted Answer

Membrane fluidity decreases and $T_m$ increases

Question 8

Which of the following best describes the asymmetrical distribution of lipids in the plasma membrane?

Accepted Answer

Most glycolipids are found in the outer monolayer, while PI and PS are in the inner monolayer

Question 9

Which experimental technique is used to measure the lateral mobility of lipids in membranes?

Accepted Answer

Fluorescence Recovery After Photobleaching (FRAP)

Question 10

What is the main function of lipid rafts in cell membranes?

Accepted Answer

Facilitating cell signaling by concentrating specific proteins and lipids

Question 11

Which of the following is TRUE about transmembrane proteins?

Accepted Answer

They can have single or multiple membrane-spanning segments

Question 12

Which type of glycosylation involves the attachment of a carbohydrate to the nitrogen atom of an asparagine residue?

Accepted Answer

N-linked glycosylation

Question 13

A cell is exposed to a temperature below its membrane's $T_m$. What is the most likely consequence?

Accepted Answer

Membrane activities that rely on fluidity are reduced

Question 14

Which of the following is a function of membrane proteins?

Accepted Answer

Solute transport across membranes

Question 15

Which of the following statements about freeze-fracture microscopy is correct?

Accepted Answer

It reveals the mosaic distribution of proteins in the membrane

Question 16

Which of the following membrane proteins is covalently attached to a lipid molecule?

Accepted Answer

Lipid-anchored membrane protein

Question 17

Which of the following is the main sterol found in fungal cell membranes?

Accepted Answer

Ergosterol

Question 18

Which of the following statements about membrane asymmetry is TRUE?

Accepted Answer

Membrane asymmetry is established during synthesis and tends to be maintained

Question 19

Which of the following is a consequence of cholesterol acting as a fluidity buffer in membranes?

Accepted Answer

It prevents fatty acid chains from packing tightly at low temperatures

Question 20

Which of the following is TRUE regarding the orientation of glycoproteins in the membrane?

Accepted Answer

Carbohydrate chains are always oriented toward the exoplasmic domain

Membranes: Their Structure, Function, and Chemistry (Chapter 7 Study Notes)

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