Question 1

Which of the following statements best explains why triacylglycerols are efficient molecules for energy storage in animals compared to carbohydrates?

Accepted Answer

Triacylglycerols are highly reduced and anhydrous, providing more than twice the energy per gram compared to carbohydrates.

Question 2

Which of the following fatty acids is a C16 saturated fatty acid commonly found in animals and plants?

Accepted Answer

Palmitic acid

Question 3

A membrane's transition temperature ($$T_m) $$increases with which of the following changes?

Accepted Answer

Increasing both the chain length and the degree of saturation of fatty acids

Question 4

Which structural feature of phospholipids is responsible for the formation of bilayer membranes?

Accepted Answer

Amphipathic nature with two hydrophobic tails and a polar head group

Question 5

Which of the following is TRUE regarding the role of cholesterol in biological membranes?

Accepted Answer

Cholesterol broadens the temperature range of phase transition by disrupting ordered lipid packing.

Question 6

Which of the following best describes the difference between sphingolipids and phosphoglycerides?

Accepted Answer

Sphingolipids use sphingosine as a backbone, while phosphoglycerides use glycerol.

Question 7

Which of the following phosphoglycerides is commonly found in biological membranes and contains a choline head group?

Accepted Answer

Phosphatidylcholine

Question 8

A patient presents with nerve cell dysfunction due to abnormal myelin formation. Which class of lipids is most likely implicated in this condition?

Accepted Answer

Sphingolipids

Question 9

Which of the following best explains why biological membranes are described as asymmetric?

Accepted Answer

The inner and outer leaflets of the membrane have different lipid compositions.

Question 10

Which process is required for the transverse diffusion (flip-flop) of lipids across the bilayer and why?

Accepted Answer

Facilitated diffusion via flippases, because the polar head group must cross the hydrophobic core.

Question 11

Which of the following best describes the function of lipid rafts in cell membranes?

Accepted Answer

They serve as rigid platforms for protein sorting and signaling due to their high cholesterol and glycosphingolipid content.

Question 12

Which of the following equations correctly represents the formation of a triacylglycerol from glycerol and three fatty acids?

Accepted Answer

$$\mathrm{Glycerol} + 3\ \mathrm{Fatty\ acids} \rightarrow \mathrm{Triacylglycerol} + 3\ \mathrm{H_2O}$$

Question 13

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Membrane fluidity is maintained over a range of temperatures by having a mixed lipid composition.

Question 14

Which of the following is a key difference between micelles and bilayers formed by lipids?

Accepted Answer

Micelles are spherical structures formed by single-tailed lipids, while bilayers are planar structures formed by double-tailed lipids.

Question 15

Which of the following best explains why polar bears rely on triacylglycerides for energy during hibernation?

Accepted Answer

Triacylglycerides are highly reduced and anhydrous, allowing for efficient long-term energy storage.

Question 16

Which of the following is NOT a component of a typical phospholipid found in biological membranes?

Accepted Answer

Steroid ring structure

Question 17

Which of the following best describes the effect of cis double bonds in fatty acid tails on membrane structure?

Accepted Answer

Cis double bonds introduce kinks, decreasing packing density and increasing fluidity.

Question 18

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

Accepted Answer

Catalyze the transverse movement of lipids from one leaflet to another using ATP.

Question 19

Which of the following best explains why membrane composition varies between the inner and outer leaflets of a bilayer?

Accepted Answer

To maintain membrane fluidity and support specific cellular functions.

Fatty Acids and Lipids: Structure, Function, and Membrane Dynamics

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