11. During the first few minutes of physical activity the body relies on anaerobic energy production from ATP and what other high-energy molecule?

A. adenosine phosphate

B. GTP

C. creatine phosphate

D. GMP

12. Adults have approximately how much glycogen stored within their muscles?

A. 200-500 g

B. 100-200 g

C. 400-600 g

D. Muscles do not store glycogen.

13. Adults have approximately how much glycogen stored within their liver?

A. 200-500 g

B. 60-120 g

C. 150-200 g

D. The liver does not store glycogen.

14. The human body stores about how many kilocalories of energy as glycogen?

A. 1,000

B. 2,600

C. 3,600

D. 1,500

15. Glycogen stores predominantly utilized by the brain are derived from

A. liver glycogen.

B. kidney glycogen.

C. muscle glycogen.

D. brain glycogen.

16. When the mitochondria lack adequate oxygen during activity, what product is formed from pyruvate?

A. oxaloacetate

B. lactate

C. malate

D. alpha-ketoglutarate

17. Once shuttled to the liver, lactate can be converted back to glucose via the

A. malate-aspartate shuttle.

B. pentose-phosphate shuttle.

C. Cori cycle.

D. TCA cycle.

18. The buildup of lactate during strenuous exercise can negatively affect performance due to the

A. reduction of pH within the tissue.

B. increase in pH within the tissue.

C. reduction in blood volume within the tissue.

D. increase in blood volume within the tissue.

19. What is the primary fuel source for muscles during high-intensity activity?

A. fat

B. protein

C. amino acids

D. carbohydrates

20. What happens to blood and liver glycogen stores after prolonged, intense exercise?

A. They increase slightly.

B. They increase substantially.

C. They decrease slightly.

D. They decrease substantially.