Nutrition and Energy Systems Flashcards

Which energy system predominates during a 400-meter sprint?

Answer: Glycolytic system

The glycolytic system (anaerobic glycolysis) dominates during high-intensity efforts lasting 30 seconds to 2 minutes, such as a 400-meter sprint.

What is the primary role of insulin in nutrient metabolism?

Answer: Facilitating cellular glucose uptake

Insulin facilitates the uptake of glucose into cells by promoting GLUT4 transporter activity, lowering blood glucose levels.

During prolonged endurance exercise, what substrate shift occurs after glycogen depletion?

Answer: Increased fat oxidation via beta-oxidation

As glycogen stores deplete during prolonged exercise, the body increasingly relies on fat oxidation (beta-oxidation) to supply acetyl-CoA for the Krebs cycle.

Which vitamin is essential for the conversion of pyruvate to acetyl-CoA?

Answer: Vitamin B1 (thiamine)

Thiamine (vitamin B1) is a coenzyme required for pyruvate dehydrogenase, the enzyme that converts pyruvate to acetyl-CoA.

What is the glycemic index (GI) of a food?

Answer: A ranking of how quickly a food raises blood glucose relative to pure glucose

The glycemic index ranks foods on a scale of 0–100 based on how rapidly they raise blood glucose compared to pure glucose (GI=100).

Which of the following best describes the function of coenzyme A (CoA)?

Answer: It carries acetyl groups into the Krebs cycle

Coenzyme A acts as an acyl carrier, binding acetyl groups to form acetyl-CoA, which then enters the Krebs cycle for energy production.

A personal trainer's client wants to maximize muscle protein synthesis after resistance training. What post-workout nutrition strategy is most supported by research?

Answer: 20–40 g of high-quality protein within 1–2 hours post-exercise

Consuming 20–40 g of high-quality protein (rich in essential amino acids) within 1–2 hours post-resistance training maximally stimulates muscle protein synthesis.