4.3.3 Glycolysis and the Krebs Cycle

Question 1

the net energy output for one glucose molecule from glycolysis through the Krebs cycle is

Answer 1

• 4 ATP, 10 NADH + H+, and 2 FADH2.
• In glycolysis, two ATP were invested, and four ATP and two NADH + H+ were produced.
• · In the conversion of pyruvate to acetyl CoA, two NADH + H+ were produced.
• In the Krebs cycle, two ATP, six NADH +H+, and two FADH2 were produced.
• A net of four ATPs was produced from glycolysis through the Krebs cycle. More ATP will be produced from reduced coenzymes in the mitochondria during the electron transport chain and oxidative phosphorylation.

Question 2

Two important electron acceptors in aerobic cellular respiration are:

Answer 2

• NAD+ and FAD

Question 3

Which statement about pyruvate is false?

Answer 3

• It is a peptide

Question 4

A major function of the citric acid cycle is to

Answer 4

• generate stored energy in the form of NADH + H+

Question 5

Glycolysis takes place in the ________, fermentation takes place in the ________, and the Krebs cycle takes place in the ________.

Answer 5

• cytosol; cytosol; matrix

Question 6

If 25 micromoles of acetyl CoA enter the Krebs cycle, how many micromoles of NADH will be produced?

Answer 6

• 75

Question 7

Which of these statements is false regarding pyruvate?

Answer 7

• Pyruvate is converted to acetyl CoA and then transfered to the mitochondrial membrane where it will enter into the Kreb’s cycle.

Question 8

How many ATP are produced directly from glycolysis and the Krebs cycle for each glucose molecule that enters glycolysis?

Answer 8

• 4

Question 9

Which of the following is not a product of respiration up to the Krebs cycle (from glycolysis to the Krebs cycle):

Answer 9

• NADPH + H+

Question 10

Acetyl CoA is a ____-carbon molecule that combines with oxaloacetate, a ____-carbon molecule to form citrate, a ____-carbon molecule.

Answer 10

• 2; 4; 6