Macronutrients and Metabolism Flashcards
6 cards from real Clinical Nutritionist CCN practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Macronutrients and Metabolism flashcards as text
Which lipoprotein is responsible for transporting cholesterol from peripheral tissues back to the liver?
Answer: HDL
High-density lipoprotein (HDL) mediates reverse cholesterol transport, carrying excess cholesterol from tissues to the liver for excretion.
What is the primary fuel source for the brain under normal fed conditions?
Answer: Glucose
The brain relies almost exclusively on glucose for energy under normal conditions because fatty acids cannot cross the blood-brain barrier efficiently.
During beta-oxidation of a 16-carbon saturated fatty acid, how many acetyl-CoA molecules are produced?
Answer: 8
Each round of beta-oxidation cleaves a 2-carbon acetyl-CoA unit, so a 16-carbon fatty acid yields 8 acetyl-CoA molecules.
Which enzyme is the rate-limiting step of fatty acid synthesis?
Answer: Acetyl-CoA carboxylase
Acetyl-CoA carboxylase catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, the committed and rate-limiting step in fatty acid synthesis.
What is the thermic effect of food (TEF) for dietary protein compared to carbohydrates and fat?
Answer: 20-30% for protein vs 5-10% for carbs and 0-3% for fat
Protein has the highest thermic effect (20-30%), meaning it requires the most energy to digest, absorb, and metabolize compared to other macronutrients.
Which metabolic state is characterized by elevated blood ketone bodies, typically seen during prolonged fasting or very low carbohydrate intake?
Answer: Ketosis
Ketosis occurs when the liver produces ketone bodies (acetoacetate, beta-hydroxybutyrate, acetone) from acetyl-CoA during states of low carbohydrate availability.
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