Question 1

Which of the following is NOT a primary function of biological membranes as described in Chapter 7?

Accepted Answer

Synthesizing DNA during cell division

Question 2

The fluid mosaic model of membrane structure is supported by which experimental technique that reveals the distribution of proteins within the lipid bilayer?

Accepted Answer

Freeze-fracture electron microscopy

Question 3

Gorter and Grendel’s classic experiment in 1925 led to the proposal of the lipid bilayer structure of membranes. What key observation did they make?

Accepted Answer

The surface area of the lipid film was twice that of the red blood cells

Question 4

Which class of membrane proteins is embedded within the lipid bilayer due to their hydrophobic regions?

Accepted Answer

Integral membrane proteins

Question 5

A mutation causes a membrane protein to lose its hydrophobic transmembrane segment. What is the most likely consequence for the protein’s localization?

Accepted Answer

It will become a peripheral membrane protein, associating with the membrane surface

Question 6

Which of the following statements about membrane fluidity is CORRECT?

Accepted Answer

Long-chain and saturated fatty acids increase the transition temperature $$T_m$$

Question 7

Sterols such as cholesterol affect membrane properties by:

Accepted Answer

Decreasing the permeability of membranes to small polar molecules

Question 8

Which of the following best explains why unsaturated fatty acids increase membrane fluidity?

Accepted Answer

Their double bonds introduce bends that prevent tight packing

Question 9

A researcher uses thin-layer chromatography (TLC) to separate membrane lipids. Which property primarily determines how far a lipid moves up the plate?

Accepted Answer

Its relative polarity

Question 10

Which of the following membrane proteins is most likely to be removed from the membrane by changing the pH or ionic strength of the solution?

Accepted Answer

Peripheral membrane protein

Question 11

A hydropathy plot of a membrane protein reveals seven distinct hydrophobic regions, each about 20 amino acids long. What is the most likely structure of this protein?

Accepted Answer

A multipass transmembrane protein forming a channel

Question 12

Which of the following is TRUE regarding membrane asymmetry?

Accepted Answer

Glycolipids are predominantly found in the outer layer of the plasma membrane

Question 13

Which type of membrane protein is most likely to function as a receptor for external signals such as hormones?

Accepted Answer

Integral membrane protein

Question 14

The ABO blood group system is determined by:

Accepted Answer

Structural differences in the carbohydrate attached to a specific glycolipid

Question 15

Which of the following best describes the role of transport ATPases in membranes?

Accepted Answer

They use the energy of ATP to actively transport ions across membranes

Question 16

A patient’s red blood cells are found to have a defective glycophorin protein. Which of the following is most likely affected?

Accepted Answer

Singlepass transmembrane protein function

Question 17

Which of the following statements about glycoproteins is CORRECT?

Accepted Answer

They are most prominent in the plasma membrane and play a role in cell-cell recognition

Question 18

Which of the following is a consequence of a membrane being below its transition temperature $$T_m$$?

Accepted Answer

Functions relying on membrane fluidity may be disrupted

Question 19

Which of the following best describes the movement of phospholipids within membranes?

Accepted Answer

Phospholipids can move both laterally and transversely (flip-flop) across the bilayer, but flip-flop is rare

Question 20

Which of the following laboratory techniques is most appropriate for separating membrane proteins by size after solubilization with detergent?

Accepted Answer

SDS-PAGE electrophoresis

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

Guida di studio - Domande di pratica

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