Fatty Acid Metabolism-AIMET

Which of the following is a primary function of beta-oxidation in fatty acid metabolism?

• Fatty acid synthesis

• Fatty acid breakdown

• Glycerol production

• Cholesterol synthesis

Answer explanation

Beta-oxidation is the process of breaking down fatty acids into acetyl-CoA for energy production.

How many carbons are typically removed in each cycle of beta-oxidation?

• 1 carbon
• 2 carbons
• 3 carbons
• 4 carbons

Answer explanation

In each cycle of beta-oxidation, a two-carbon unit in the form of an acetyl-CoA molecule is removed from the fatty acid chain.

Which enzyme is responsible for the first step of beta-oxidation, the conversion of fatty acyl-CoA to fatty enoyl-CoA?

• Acetyl-CoA carboxylase
• Fatty acid synthase
• Acyl-CoA dehydrogenase
• Carnitine palmitoyltransferase I

Answer explanation

Acyl-CoA dehydrogenase is responsible for the first step of beta-oxidation, which is the conversion of fatty acyl-CoA to fatty enoyl-CoA through the removal of two hydrogen atoms.

1. 
   During beta-oxidation, what molecule carries the electrons and protons removed from fatty acids, ultimately leading to the production of ATP?

• NADH
• FADH2
• Coenzyme A
• Cytochrome c

Answer explanation

NADH (nicotinamide adenine dinucleotide) carries the electrons and protons removed during beta-oxidation and delivers them to the electron transport chain to generate ATP.

In which cellular organelle does beta-oxidation of fatty acids primarily occur?

• Nucleus
• Ribosome
• Mitochondria
• Golgi apparatus

Answer explanation

Beta-oxidation of fatty acids primarily takes place in the mitochondria, where the enzymes and machinery required for this process are located.

What is the primary function of acetyl-CoA carboxylase in fatty acid metabolism?

• Fatty acid synthesis

• It catalyzes the conversion of acetyl-CoA to citrate
• It catalyzes the conversion of acetyl-CoA to pyruvate
• It catalyzes the conversion of acetyl-CoA to glucose

Answer explanation

Acetyl-CoA carboxylase is responsible for the carboxylation of acetyl-CoA, which is the first step in fatty acid synthesis.

What is the primary role of hormone-sensitive lipase in fatty acid metabolism?

• It catalyzes the conversion of glucose to glycogen
• It catalyzes the hydrolysis of triglycerides in adipose tissue
• It catalyzes the synthesis of cholesterol
• It catalyzes the conversion of fatty acids to triglycerides

Answer explanation

Hormone-sensitive lipase catalyzes the breakdown of triglycerides into fatty acids and glycerol.

Which hormone promotes the uptake of glucose and inhibits the breakdown of fatty acids in the liver?

• Adrenaline
• Cortisol
• Glucagon
• Insulin

Which enzyme is responsible for the conversion of acyl-CoA to 3-ketoacyl-CoA during beta-oxidation of fatty acids?

• Hexokinase
• Pyruvate kinase
• 3-ketoacyl-CoA thiolase
• Acetyl-CoA carboxylase

Answer explanation

3-ketoacyl-CoA thiolase catalyzes the final step in each cycle of beta-oxidation, converting 3-ketoacyl-CoA to acetyl-CoA.

Which of the following conditions would increase fatty acid oxidation? (Select all that apply)

• High ATP levels

• High NADH/NAD+ ratio

• Low insulin levels

• High levels of malonyl-CoA

Answer explanation

Low insulin levels and a high NADH/NAD+ ratio favor fatty acid oxidation, while high ATP levels and high malonyl-CoA levels inhibit it.