Nutrition and Energy Systems Flashcards

Which of the following amino acids are classified as branched-chain amino acids (BCAAs)?

Answer: Leucine, isoleucine, and valine

The three branched-chain amino acids are leucine, isoleucine, and valine; they are essential amino acids metabolized primarily in skeletal muscle.

What is the primary purpose of the electron transport chain (ETC)?

Answer: To use electrons from NADH and FADH2 to generate a proton gradient for ATP synthesis

The ETC accepts electrons from NADH and FADH2, passing them through a series of protein complexes to pump protons and create a gradient used by ATP synthase to produce ATP.

A client on a 2,000 kcal/day diet consumes 55% of calories from carbohydrates. How many grams of carbohydrate does this represent?

Answer: 275 g

2,000 kcal × 0.55 = 1,100 kcal from carbohydrates; 1,100 ÷ 4 kcal/g = 275 g of carbohydrates.

Which of the following is a fat-soluble vitamin?

Answer: Vitamin E

Vitamin E is a fat-soluble vitamin stored in adipose tissue and the liver, alongside vitamins A, D, and K.

What is the primary site of lipid digestion?

Answer: Small intestine

The small intestine is the primary site of fat digestion, where bile emulsifies lipids and pancreatic lipase breaks them into fatty acids and monoglycerides.

During moderate-intensity aerobic exercise lasting 60 minutes, which fuel source contributes most at the 45-minute mark in a well-fueled athlete?

Answer: Muscle glycogen and free fatty acids

During prolonged moderate aerobic exercise, muscle glycogen and free fatty acids (from adipose lipolysis) are the predominant fuel sources, with their ratio shifting toward fat over time.

What does a negative nitrogen balance indicate?

Answer: Protein breakdown exceeds synthesis, suggesting muscle loss or inadequate protein intake

Negative nitrogen balance means nitrogen excretion exceeds intake, indicating net protein catabolism and potential muscle tissue loss.