Q: Which of the following is the correct formula for the activation of a fatty acid by coenzyme A, and how many ATP equivalents are used?

$$\text{Fatty acid} + \text{CoA} + \text{ATP} \rightarrow \text{Fatty acyl-CoA} + \text{AMP} + 2\ \text{Pi}$$; uses 2 ATP equivalents

Question 1

Which of the following best describes the difference between the Delta ($$\Delta) $$and Omega ($$\omega) $$systems for naming fatty acids?

Accepted Answer

The Delta system counts double bonds from the carboxyl end, while the Omega system counts from the methyl end.

Question 2

A fatty acid is labeled as 18:3 $$\$$Delta^{9,12,15}$$. What is the equivalent omega notation?

Accepted Answer

$$18:3\ \omega-3$$

Question 3

Which enzyme is responsible for the uptake of fatty acids from the bloodstream into tissues and is regulated by insulin?

Accepted Answer

Lipoprotein lipase (LPL)

Question 4

During fatty acid $$\beta-$$oxidation, how many ATP are net produced from the complete oxidation of one molecule of palmitic acid ($$C_{16}$$)?

Accepted Answer

$$106\ 	ext{ATP}$$

Question 5

Which of the following statements about the transport of fatty acids into the mitochondrial matrix is correct?

Accepted Answer

Long-chain fatty acids require a transport system involving carnitine.

Question 6

Which of the following is a key regulatory enzyme in fatty acid synthesis, and what is its main allosteric activator?

Accepted Answer

Acetyl-CoA carboxylase (ACC); activated by cytosolic citrate

Question 7

Which of the following dietary changes is most likely to reduce serum LDL cholesterol levels?

Accepted Answer

Replacing saturated fatty acids with monounsaturated or polyunsaturated fatty acids

Question 8

Which apolipoprotein is found on LDL, VLDL, and IDL, and is considered a strong indicator of atherosclerotic cardiovascular disease risk?

Accepted Answer

ApoB-100

Question 9

A patient with hyperlipidemia is placed on a diet with a lower n-6/n-3 ratio. According to recent clinical trial findings, what is the most likely effect on their blood lipids?

Accepted Answer

Decrease in triglycerides and total cholesterol, with no change in HDL

Question 10

Which of the following best describes the role of eicosanoids derived from arachidonic acid (ARA) compared to those derived from eicosapentaenoic acid (EPA)?

Accepted Answer

ARA-derived eicosanoids promote inflammation and platelet aggregation, while EPA-derived suppress inflammation and blood clotting.

Question 11

Which of the following is NOT a function of HDL in cholesterol metabolism?

Accepted Answer

Delivers cholesterol to peripheral tissues for membrane synthesis

Question 12

Which of the following statements about the digestion and absorption of lipids is correct?

Accepted Answer

Short- and medium-chain fatty acids are absorbed directly into the portal vein.

Question 13

Which of the following is a correct sequence of events in the development of atherosclerosis?

Accepted Answer

Fatty streak formation → smooth muscle migration → fibrous cap formation → plaque rupture

Question 14

Which of the following is the correct formula for the activation of a fatty acid by coenzyme A, and how many ATP equivalents are used?

Accepted Answer

$$	ext{Fatty acid} + 	ext{CoA} + 	ext{ATP} ightarrow 	ext{Fatty acyl-CoA} + 	ext{AMP} + 2\ 	ext{Pi}$$; uses 2 ATP equivalents

Question 15

Which of the following dietary sources is highest in arachidonic acid (ARA)?

Accepted Answer

Eggs

Question 16

Which of the following statements about the competition between n-3 and n-6 fatty acids is correct?

Accepted Answer

Excess n-3 fatty acids decrease ARA synthesis.

Question 17

Which of the following is a function of eicosanoids?

Accepted Answer

Regulation of inflammatory responses and immunity

Question 18

A patient has a total cholesterol of $$6.0\ 	ext{mmol/L}$$ and serum triglycerides of $$2.0\ 	ext{mmol/L}. $$According to early screening guidelines, what is their risk status for cardiovascular disease (CVD)?

Accepted Answer

Both cholesterol and triglycerides are above risk thresholds

Question 19

Which of the following interventions is LEAST likely to reduce serum cholesterol?

Accepted Answer

Increasing intake of saturated fats

Metabolic Pathways for Lipids: Digestion, Absorption, Metabolism, and Cardiovascular Implications

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