Question 1

Which of the following best describes the amphipathic nature of most lipids?

Accepted Answer

They contain both hydrophobic and hydrophilic regions.

Question 2

Which statement correctly explains why fats are efficient for energy storage in organisms?

Accepted Answer

Their carbon atoms are highly reduced, allowing for more energy release upon oxidation.

Question 3

A fatty acid with 18 carbons and one cis double bond is classified as:

Accepted Answer

An unsaturated fatty acid

Question 4

Which of the following is a major class of membrane-forming lipids that contains a phosphate group in its head?

Accepted Answer

Glycerophospholipids

Question 5

What is the main structural difference between a micelle and a lipid bilayer?

Accepted Answer

Micelles are formed by lipids with one hydrophobic tail, while bilayers are formed by lipids with two hydrophobic tails.

Question 6

Which of the following best describes the role of cholesterol in biological membranes?

Accepted Answer

It disrupts regular fatty acid chain packing, increasing membrane fluidity.

Question 7

Which equation correctly represents the stoichiometry of the Na$$^+-K$^+$$ ATPase reaction?

Accepted Answer

$$2K^+_{(out)} + 3Na^+_{(in)} + ATP + H_2O \rightarrow 2K^+_{(in)} + 3Na^+_{(out)} + ADP + P_i$$

Question 8

Which of the following is TRUE regarding facilitated transport across membranes?

Accepted Answer

It is accelerated by specific pores, carriers, or permeases.

Question 9

A patient with cystic fibrosis has a defect in which type of membrane transporter?

Accepted Answer

ABC transporter (ATP-binding cassette transporter)

Question 10

Which of the following best describes the function of aquaporins in erythrocytes?

Accepted Answer

They facilitate rapid water transport to maintain osmotic balance.

Question 11

Which of the following membrane lipids contains a carbohydrate linked to its head group?

Accepted Answer

Glycoglycerolipids

Question 12

Which of the following is a property of membrane rafts?

Accepted Answer

They are dynamic domains rich in cholesterol and sphingolipids.

Question 13

Which of the following statements about the fluid mosaic model is correct?

Accepted Answer

Membrane proteins and lipids can diffuse laterally within the plane of the membrane.

Question 14

Which of the following best describes a symport system?

Accepted Answer

It transports two solutes across the membrane in the same direction.

Question 15

Which of the following is a function of fats (triacylglycerides) in animals?

Accepted Answer

Thermal insulation

Question 16

Which of the following is TRUE about the sodium-glucose cotransport system?

Accepted Answer

The sodium gradient provides the driving force for glucose transport.

Question 17

Which of the following is a distinguishing feature of sphingolipids?

Accepted Answer

A fatty acid is linked to the amino alcohol sphingosine via an amide bond.

Question 18

Which of the following is a direct consequence of increasing the number of cis double bonds in a fatty acid chain?

Accepted Answer

Increased membrane fluidity

Question 19

Which of the following is a function of glycosphingolipids in biological membranes?

Accepted Answer

They serve as recognition sites due to their glycan head groups.

Question 20

Which of the following best explains why polar or charged solutes diffuse slowly across biological membranes?

Accepted Answer

The hydrophobic core of the membrane acts as a barrier to polar/charged molecules.

Lipids, Membranes, and Membrane Transport: Structure and Function

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