Krebs Cycle

Question 1

Segment A

Answer 1

• Pyruvate from glycolysis is oxidized into acetyl group that feeds into citrate cycle
• 2-carbon acetyl CoA combines with 4-carbon oxaloacetate
• produces 6-carbon compound citrate

Question 2

Segment B

Answer 2

• oxidation reactions produce NADH
• loss of 2 CO2s produces a new 4-carbon compound
• 1 ATP is directly generated for each acetyl group fed in

Question 3

Segment C

Answer 3

• two additional oxidations generate another NADH
• also produces and FADH2
• regenerates the original 4-carbon oxaloacetate

Question 4

GTP

Answer 4

made in Krebs cycle from succinyl to succinate through substrate level phosphorylation
GDP with one more phosphate
can transfer its phosphate to ADP to make ATP
can be used in processes like ribosome formation

Question 5

why can FADH and NADH be used as energy currency like ATP

Answer 5

large and expensive (require lots of energy)

unstable enough to not be useful for long term storage

Question 6

products of krebs cycle

Answer 6

8 NADH + 2 FADH

Question 7

oxidative decarboxylation by pyruvate dehydrogenase complex

Answer 7

reactants: pyruvate, h+ ion, coenzyme A sulfhydryl
products: carbon dioxide, Acetyl CoA
h from Coenzyme A sulfhydryl and h+ ion bind to NAD+ to form NADH