Q: Which equation best represents the hydrolysis of a triacylglycerol by lipase?

$$\text{Triacylglycerol} + 3\ \text{H}_2\text{O} \rightarrow \text{Glycerol} + 3\ \text{Fatty acids}$$

Q: Which head group is present in phosphatidylcholine?

$$\text{CH}_2\text{CH}_2\text{N}^+(\text{CH}_3)_3$$

Question 1

Which structural feature distinguishes triacylglycerols from glycerophospholipids?

Accepted Answer

Triacylglycerols contain three fatty acyl chains esterified to glycerol, while glycerophospholipids contain two fatty acyl chains and a phosphate group attached to glycerol.

Question 2

Which equation best represents the hydrolysis of a triacylglycerol by lipase?

Accepted Answer

$$	ext{Triacylglycerol} + 3\ 	ext{H}_2	ext{O} ightarrow 	ext{Glycerol} + 3\ 	ext{Fatty acids}$$

Question 3

Which property explains why triacylglycerols are used for long-term energy storage in adipocytes?

Accepted Answer

They are highly hydrophobic and can be densely packed without water, maximizing energy storage per unit mass.

Question 4

Which head group is present in phosphatidylcholine?

Accepted Answer

$$	ext{CH}_2	ext{CH}_2	ext{N}^+(	ext{CH}_3)_3$$

Question 5

Which of the following best describes the difference in structure between micelles and bilayers?

Accepted Answer

Micelles are formed by wedge-shaped fatty acids, while bilayers are formed by cylindrical phospholipids.

Question 6

Which enzyme selectively hydrolyzes the fatty acid at the C2 position of glycerophospholipids?

Accepted Answer

Phospholipase A2

Question 7

Plasmalogens are distinguished from other phospholipids by which structural feature?

Accepted Answer

A vinyl ether linkage at the C1 position of glycerol

Question 8

Which of the following is a major function of sphingomyelin in the human body?

Accepted Answer

It is a major component of myelin sheaths that insulate nerve cells.

Question 9

Which disease is associated with deficiencies in sphingolipid degradation?

Accepted Answer

Tay-Sachs disease

Question 10

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

Accepted Answer

A fatty acid linked to the NH2 group of sphingosine via an amide bond

Question 11

Which of the following is true about gangliosides?

Accepted Answer

They contain a carbohydrate chain attached to the C3 atom of ceramide and are mostly found in the CNS.

Question 12

Which of the following best explains why olive oil solidifies at lower temperatures compared to animal fat?

Accepted Answer

Olive oil contains more unsaturated fatty acids, which lower its melting point.

Question 13

Which of the following is a common head group in glycerophospholipids?

Accepted Answer

Choline

Question 14

Which of the following best describes the role of plasmalogens in membranes?

Accepted Answer

They contribute to membrane stability and organization of lipid rafts.

Question 15

Which of the following is true about the composition of myelin sheaths?

Accepted Answer

They are rich in lipids, including sphingomyelin and cerebrosides.

Question 16

Which of the following best describes the function of phospholipases in signal transduction?

Accepted Answer

They hydrolyze specific bonds in phospholipids, generating signaling molecules.

Question 17

Which of the following is a distinguishing feature of cerebrosides?

Accepted Answer

They contain a monosaccharide group attached to the C3 atom of ceramide.

Question 18

Which of the following best describes the amphipathic nature of glycerophospholipids?

Accepted Answer

They have a hydrophobic tail and a hydrophilic head, allowing them to form bilayers.

Question 19

Which of the following is a consequence of the hydrophobic nature of triacylglycerols?

Accepted Answer

They are less soluble in water and can be stored without associated water, increasing energy density.

Triacylglycerols, Phospholipids, and Sphingolipids: Structure, Function, and Disease

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