Question 1

Which of the following statements best explains why triacylglycerols yield more energy per gram than hydrated glycogen in animals?

Accepted Answer

Triacylglycerols are less oxidized and stored anhydrously, making them more energy-dense.

Question 2

Which of the following fatty acids is polyunsaturated?

Accepted Answer

Linoleate

Question 3

A mutation causes a cell to produce only saturated fatty acids in its membrane lipids. What is the most likely effect on the cell membrane at low temperatures?

Accepted Answer

The membrane will become more rigid and gel-like.

Question 4

Which of the following best describes the structure of a glycerophospholipid?

Accepted Answer

A glycerol backbone with two fatty acids and a phosphoryl-X group.

Question 5

Which enzyme would cleave the bond between the glycerol backbone and the phosphate group in a phospholipid?

Accepted Answer

Phospholipase C

Question 6

Which of the following is a distinguishing feature of plasmalogens compared to other glycerophospholipids?

Accepted Answer

They have an ether linkage at C1 instead of an ester linkage.

Question 7

Which of the following statements about sphingolipids is correct?

Accepted Answer

They are major components of biological membranes.

Question 8

Gangliosides are important in cell recognition and act as receptors for certain toxins. Which structural feature is unique to gangliosides?

Accepted Answer

A complex oligosaccharide head group

Question 9

Which of the following statements about cholesterol is FALSE?

Accepted Answer

Cholesterol is highly flexible due to its long hydrocarbon tail.

Question 10

Vitamin K deficiency can lead to excessive bleeding because:

Accepted Answer

It prevents the carboxylation of Glu residues in clotting proteins.

Question 11

Which of the following best describes the role of vitamin E in biological membranes?

Accepted Answer

It functions as an antioxidant, preventing oxidative damage.

Question 12

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

Accepted Answer

Membrane proteins float in a sea of lipids and can diffuse laterally.

Question 13

Which of the following best explains why lateral diffusion of lipids in a bilayer is rapid, while transverse diffusion (flip-flop) is very slow?

Accepted Answer

Transverse diffusion requires the polar head group to cross the hydrophobic core.

Question 14

Which of the following is a correct statement about the effect of fatty acid chain length and saturation on membrane fluidity?

Accepted Answer

Increasing chain length and saturation decreases membrane fluidity.

Question 15

Which of the following best describes a peripheral membrane protein?

Accepted Answer

It can be dissociated from the membrane by high salt or pH changes.

Question 16

Which of the following is a function of eicosanoids derived from arachidonic acid?

Accepted Answer

They regulate blood pressure and inflammation.

Question 17

Which of the following best describes the amphiphilic nature of fatty acids?

Accepted Answer

They have a polar carboxylic acid head and a nonpolar hydrocarbon tail.

Question 18

Which of the following is a correct statement about the distribution of phospholipids in the plasma membrane?

Accepted Answer

Phosphatidylcholine is more abundant in the outer leaflet.

Question 19

Which of the following best describes the structure of a ceramide?

Accepted Answer

A sphingosine backbone with a fatty acid attached via an amide bond.

Question 20

Which of the following is a correct statement about lipid-linked proteins?

Accepted Answer

They are covalently attached to lipids such as prenyl, myristoyl, or palmitoyl groups.

Lipids and Biological Membranes: Structure, Function, and Classification

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