Fat Burning Metabolism and Energy Systems 1 — Questions and Answers
Question 1: What is the primary fuel source used during low-intensity aerobic exercise for fat burning?
- Glycogen
- Free fatty acids (Correct answer)
- Dietary protein
- Blood glucose
Correct answer: Free fatty acids
During low-intensity aerobic exercise, the body primarily oxidizes free fatty acids because oxygen availability supports the slower but more efficient fat metabolism pathway.
Question 2: Which metabolic process breaks down stored triglycerides into free fatty acids and glycerol?
- Gluconeogenesis
- Lipolysis (Correct answer)
- Lipogenesis
- Glycolysis
Correct answer: Lipolysis
Lipolysis is the metabolic process that hydrolyzes stored triglycerides into free fatty acids and glycerol, releasing them into the bloodstream for use as fuel.
Question 3: The 'fat-burning zone' is typically defined as what percentage of maximum heart rate?
- 40–50%
- 60–70% (Correct answer)
- 80–90%
- 95–100%
Correct answer: 60–70%
The fat-burning zone is generally 60–70% of maximum heart rate, where the body uses a higher proportion of fat relative to carbohydrates as fuel.
Question 4: Which organelle is the primary site of beta-oxidation of fatty acids?
- Nucleus
- Ribosome
- Mitochondria (Correct answer)
- Endoplasmic reticulum
Correct answer: Mitochondria
Mitochondria are the site of beta-oxidation, where fatty acids are cleaved into acetyl-CoA units that enter the Krebs cycle to generate ATP.
Question 5: Basal Metabolic Rate (BMR) accounts for approximately what percentage of total daily energy expenditure in a sedentary adult?
- 10–20%
- 30–45%
- 60–75% (Correct answer)
- 85–95%
Correct answer: 60–75%
BMR accounts for 60–75% of total daily energy expenditure, representing calories burned to maintain basic physiological functions at rest.
Question 6: What is Excess Post-exercise Oxygen Consumption (EPOC)?
- The oxygen debt accumulated during warm-up
- The elevated metabolic rate that persists after high-intensity exercise (Correct answer)
- The increased breathing rate during aerobic activity
- The oxygen used to digest a post-workout meal
Correct answer: The elevated metabolic rate that persists after high-intensity exercise
EPOC, sometimes called the 'afterburn effect,' is the elevated oxygen consumption and calorie burning that continues after intense exercise as the body restores itself to baseline.
Question 7: Which hormone primarily mobilizes free fatty acids from adipose tissue during exercise?
- Insulin
- Glucagon
- Epinephrine (adrenaline) (Correct answer)
- Oxytocin
Correct answer: Epinephrine (adrenaline)
Epinephrine activates beta-adrenergic receptors on fat cells, stimulating lipolysis and releasing free fatty acids into the bloodstream for use as fuel during exercise.
Fat Burning Metabolism and Energy Systems 1
What is the primary fuel source used during low-intensity aerobic exercise for fat burning?