Question

the krebs cycle forms many products. which option lists the correct products of the krebs cycle after 1 molecule of glucose goes through it? (1 point)
○ net 2 nad+, 2 atp, 4 co₂, 2 fadh
○ net 4 nadh, 4 atp, 8 co₂, 4 fadh₂
○ 6 nadh, 2 atp, 4 co₂, and 2 fadh₂
○ net 1 nadh, 1 atp, 2 co₂, 1 fadh₂

Explanation:

1. Recall the Krebs cycle (Citric Acid Cycle) process: One molecule of glucose is broken down into 2 molecules of pyruvate during glycolysis. Each pyruvate enters the Krebs cycle, so the Krebs cycle runs twice per glucose molecule.
2. Analyze the products per turn of the Krebs cycle:

• Per turn (per pyruvate - derived acetyl - CoA), the Krebs cycle produces 3 NADH, 1 ATP (or GTP), 2 \(CO_2\), and 1 \(FADH_2\).

1. Calculate the products for 2 turns (1 glucose molecule):

• For NADH: \(3\times2 = 6\) NADH.
• For ATP: \(1\times2=2\) ATP.
• For \(CO_2\): \(2\times2 = 4\) \(CO_2\).
• For \(FADH_2\): \(1\times2=2\) \(FADH_2\).
• Now check the options:
• The first option has incorrect molecules (NAD+ instead of NADH, FADH instead of \(FADH_2\)).
• The second option has incorrect quantities (4 NADH, 4 ATP, 8 \(CO_2\), 4 \(FADH_2\) are wrong as per the calculation).
• The third option (6 NADH, 2 ATP, 4 \(CO_2\), and 2 \(FADH_2\)) matches our calculation.
• The fourth option has incorrect quantities (1 NADH, 1 ATP, 2 \(CO_2\), 1 \(FADH_2\) is per turn, not for 2 turns).

Answer:

6 NADH, 2 ATP, \(4\ CO_2\), and \(2\ FADH_2\) (the third option in the given choices)