11) Carbohydrate metabolism involves the reactants, glucose plus oxygen, and the resultant products, ________.

A) pyruvate and nitrogen

B) carbon dioxide and water

C) water and sucrose

D) nitrogen and hydrogen

E) water and pyruvate

12) Most cells generate ATP and other high-energy compounds by breaking down carbohydrates, especially ________.

A) ribose

B) galactose

C) sucrose

D) fructose

E) glucose

13) Which of the following is the first intermediate formed in the citric acid cycle?

A) coenzyme A

B) pyruvate

C) FADH2

D) citric acid

E) oxygen

14) Regarding the citric acid cycle, which molecule participates in a complex reaction involving NAD and coenzyme A within the mitochondrion?

A) pyruvate

B) citric acid

C) ATP

D) oxygen

E) FADH2

15) In the electron transport system (ETS), which of the following are pumped into the intermembrane space, providing the concentration gradient essential for the generation of ATP?

A) oxygen molecules

B) water molecules

C) ATP molecules

D) hydrogen ions

E) cytochromes

16) When actively contracting, skeletal muscles catabolize glucose, but at rest they rely on which of the following?

A) proteins

B) glycogen

C) nucleic acids

D) fatty acids

E) amino acids

17) Which of the following may not be used for gluconeogenesis because their breakdown produces acetyl CoA?

A) fatty acids

B) complex carbohydrates

C) glycerol

D) nucleic acids

E) glycogen

18) Lipids that can diffuse easily across plasma membranes are called ________.

A) triglycerides

B) steroids

C) albumins

D) high-density lipoproteins

E) free fatty acids

19) Lipogenesis of steroids and almost all fatty acids begins with

A) glucose.

B) amino acids.

C) fatty acids.

D) acetyl CoA.

E) succinyl CoA.

20) Molecules that carry excess cholesterol from peripheral tissues to the liver for storage or secretion in the bile are called

A) low-density lipoproteins (LDLs).

B) high-density lipoproteins (HDLs).

C) fatty acids.

D) steroids.

E) chylomicrons.