Question 1

Which of the following statements best explains why unsaturated fatty acids are typically liquid at room temperature, while saturated fatty acids are solid?

Accepted Answer

Unsaturated fatty acids have cis double bonds that introduce kinks, preventing tight packing of molecules.

Question 2

A fatty acid with the formula $$\mathrm{C$$_{18}$$H_{36}O_2$}$$ and no double bonds is most likely:

Accepted Answer

Stearic acid, a saturated fatty acid

Question 3

Which of the following best describes the structure of a triacylglycerol molecule?

Accepted Answer

Three fatty acids esterified to a glycerol backbone

Question 4

Why are linoleic and linolenic acids considered essential fatty acids (EFAs)?

Accepted Answer

Humans cannot introduce double bonds beyond carbon 9 in the fatty acid chain, so these must be obtained from the diet.

Question 5

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

Accepted Answer

They form a bilayer with hydrophilic heads facing outward and hydrophobic tails inward.

Question 6

A patient has high levels of LDL and low levels of HDL in their blood. What health risk is most directly associated with this lipid profile?

Accepted Answer

Increased risk of atherosclerosis and cardiovascular disease

Question 7

Which of the following best describes the process of hydrogenation of vegetable oils?

Accepted Answer

Addition of hydrogen atoms to unsaturated fatty acids, converting them to saturated fatty acids

Question 8

Which of the following equations correctly represents the general formula for a fatty acid?

Accepted Answer

$$\mathrm{R-COOH}$$

Question 9

Which of the following statements about cholesterol is FALSE?

Accepted Answer

Cholesterol is found in both animal and plant cell membranes.

Question 10

Which lipoprotein is primarily responsible for transporting dietary lipids from the intestine to peripheral tissues?

Accepted Answer

Chylomicrons

Question 11

A person is fasting for 24 hours. Which of the following best describes the body's use of triacylglycerols during this period?

Accepted Answer

Triacylglycerols are broken down to provide energy after glycogen stores are depleted.

Question 12

Which of the following is NOT a function of triacylglycerols in the human body?

Accepted Answer

Serving as a major component of cell membranes

Question 13

Which of the following best explains why the human body cannot synthesize certain polyunsaturated fatty acids?

Accepted Answer

Humans lack desaturase enzymes to introduce double bonds beyond carbon 9 of the fatty acid chain.

Question 14

Which of the following statements about eicosanoids is correct?

Accepted Answer

They are derived from arachidonic acid and act as local signaling molecules.

Question 15

A patient with familial hypercholesterolemia is most likely to have which of the following?

Accepted Answer

Overproduction of cholesterol leading to increased risk of atherosclerosis

Question 16

Which of the following best describes the role of bile salts in lipid digestion?

Accepted Answer

They emulsify dietary lipids, increasing the surface area for enzyme action.

Question 17

Which of the following is a correct statement about the function of steroid hormones derived from cholesterol?

Accepted Answer

Cortisol increases gluconeogenesis and inhibits protein synthesis in muscle.

Question 18

Which of the following best explains why triacylglycerols provide more energy per gram than carbohydrates?

Accepted Answer

Triacylglycerols have a higher proportion of reduced carbon atoms, yielding more ATP upon oxidation.

Question 19

Which of the following is a function of HDL (high-density lipoprotein) in lipid metabolism?

Accepted Answer

It removes excess cholesterol from cells and transports it to the liver for excretion.

Lipid Structure and Function: Fatty Acids in Nutrition

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