Question 1

Which of the following best explains why fats (triacylglycerides) are efficient molecules for energy storage in living organisms?

Accepted Answer

Their carbon atoms are highly reduced, yielding more energy upon oxidation.

Question 2

A fatty acid with the structure $$\mathrm{CH_3$(CH_2$)7CH=CH(CH_2$)7COOH} is $$best classified as:

Accepted Answer

A monounsaturated fatty acid

Question 3

Which of the following statements about membrane lipids is CORRECT?

Accepted Answer

Sphingolipids contain a fatty acid linked to sphingosine via an amide bond.

Question 4

Which of the following best describes the effect of increasing the number of cis double bonds in a fatty acid chain on membrane fluidity?

Accepted Answer

Membrane fluidity increases due to kinks in the fatty acid chains.

Question 5

Which of the following is a distinguishing feature of cholesterol compared to other membrane lipids?

Accepted Answer

It is the precursor to all steroids and has a tetracyclic hydrocarbon structure.

Question 6

A patient with a genetic defect in ABC transporters is most likely to experience which of the following clinical consequences?

Accepted Answer

Defective chloride ion transport, as seen in cystic fibrosis

Question 7

Which of the following best describes the stoichiometry of the Na$$^+-K$^+$$ ATPase reaction?

Accepted Answer

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

Question 8

Which of the following is TRUE regarding the fluid mosaic model of biological membranes?

Accepted Answer

Lipids and proteins can diffuse laterally within the plane of the membrane.

Question 9

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

Accepted Answer

They allow for the rapid and selective transport of water, maintaining osmotic balance.

Question 10

A researcher observes that a certain membrane protein transports two different solutes in opposite directions across the membrane. This protein is best classified as:

Accepted Answer

An antiporter

Question 11

Which of the following statements about membrane transport is CORRECT?

Accepted Answer

Active transport moves solutes against their concentration gradient, often using ATP hydrolysis.

Question 12

Which of the following membrane lipids is characterized by a carbohydrate attached to its head group?

Accepted Answer

Glycoglycerolipid

Question 13

A mutation that prevents the formation of lipid rafts in a cell membrane would most likely disrupt which cellular process?

Accepted Answer

Cell signaling and protein sorting into organelles

Question 14

Which of the following is a property shared by most biological membrane lipids but NOT by cholesterol?

Accepted Answer

They are highly amphipathic with distinct hydrophilic and hydrophobic regions.

Question 15

Which of the following best explains why polar or charged solutes cross biological membranes slowly by nonmediated transport?

Accepted Answer

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

Question 16

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

Accepted Answer

Glucose transport is coupled to the favorable movement of sodium down its gradient.

Question 17

Which of the following is a correct description of the structure of a triacylglycerol?

Accepted Answer

A glycerol backbone esterified with three fatty acids

Question 18

Which of the following is a function of membrane rafts?

Accepted Answer

Serving as dynamic domains rich in cholesterol and sphingolipids involved in cell signaling

Question 19

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

Accepted Answer

They contain both hydrophilic and hydrophobic regions.

Lipids, Membranes, and Transport: Structure and Function in Biochemistry

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