CSCS: Bioenergetics of Exercise & Training Flashcards
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Read the first 7 CSCS: Bioenergetics of Exercise & Training flashcards as text
Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA, linking glycolysis to the Krebs cycle?
Answer: Pyruvate dehydrogenase
Pyruvate dehydrogenase converts pyruvate to acetyl-CoA in the mitochondrial matrix, allowing aerobic carbohydrate oxidation to continue.
The oxygen deficit is best described as the difference between:
Answer: Oxygen required and oxygen consumed during early exercise
Oxygen deficit is the gap between the oxygen theoretically required and the oxygen actually consumed during the initial non-steady-state phase of exercise.
At what blood lactate concentration (mmol/L) is the lactate threshold (LT) classically defined in many laboratory protocols?
Answer: 4 mmol/L
The 4 mmol/L fixed blood lactate threshold (often called OBLA) is a widely used marker in laboratory settings, though individual thresholds vary.
Which of the following best explains why beta-oxidation is considered highly efficient for energy production?
Answer: It yields significantly more ATP per gram than carbohydrate
Fat yields approximately 9 kcal/g versus 4 kcal/g for carbohydrate, resulting in more total ATP per gram during beta-oxidation.
During maximal sprint exercise lasting approximately 6 seconds, which energy system contributes the greatest percentage of ATP?
Answer: Phosphagen (ATP-PCr) system
The phosphagen system dominates ATP production during maximal efforts lasting ~6 seconds due to the immediate availability of PCr.
Which metabolic byproduct of anaerobic glycolysis directly inhibits phosphofructokinase (PFK)?
Answer: Hydrogen ions (H+)
Accumulation of hydrogen ions (decreased pH) inhibits PFK, which is the rate-limiting enzyme of glycolysis, slowing ATP production.
An athlete performs repeated 30-second all-out sprints with 3-minute rest periods. Which adaptation most directly improves performance on later sprint bouts?
Answer: Enhanced PCr resynthesis rate
PCr resynthesis during recovery is primarily aerobic, so enhanced aerobic capacity improves PCr recovery between sprint bouts.