TCA-ETC Flashcards
What is another name for the TCA cycle →
Krebs cycle
Where do TCA cycle reactions occur →
Mitochondria
What is produced per acetyl-CoA in the TCA cycle →
3 NADH, 1 FADH₂, 2 CO₂, 1 GTP
How many ATP equivalents are generated per acetyl-CoA via the TCA cycle →
10 ATP
Which substrate enters the TCA cycle from glycolysis →
Acetyl-CoA
How many carbons are in citrate →
6 carbons
How many NADH are produced per acetyl-CoA in the TCA cycle →
3 NADH
How many FADH₂ are produced per acetyl-CoA in the TCA cycle →
1 FADH₂
How many GTP are produced per acetyl-CoA in the TCA cycle →
1 GTP
Which enzyme catalyzes citrate formation from oxaloacetate and acetyl-CoA →
Citrate synthase
Which three TCA enzymes are irreversible →
Citrate synthase, isocitrate dehydrogenase, α-KG dehydrogenase
Which TCA enzyme requires the same cofactors as pyruvate dehydrogenase →
α-ketoglutarate dehydrogenase
What is the mnemonic for remembering citrate’s role in fatty acid synthesis →
Citrate is Krebs’ starting substrate for making oxaloacetate
Which complex receives electrons from NADH →
Complex I
Which complex receives electrons from FADH₂ →
Complex II (succinate dehydrogenase)
How many ATP are produced per NADH in the ETC →
2.5 ATP
How many ATP are produced per FADH₂ in the ETC →
1.5 ATP
What does passage of electrons through the ETC create →
A proton gradient across the inner mitochondrial membrane
What is the function of the proton gradient in oxidative phosphorylation →
Drives ATP production via ATP synthase (Complex V)
How many net ATP are produced per glucose via aerobic metabolism (malate-aspartate shuttle) →
32 ATP (heart and liver)
How many net ATP are produced per glucose via aerobic metabolism (glycerol-3-phosphate shuttle) →
30 ATP (muscle)
How many net ATP are produced per glucose via anaerobic glycolysis →
2 ATP
What shuttles allow NADH from glycolysis to enter mitochondria →
Malate-aspartate and glycerol-3-phosphate shuttles
What do uncoupling proteins do in mitochondria →
Increase inner mitochondrial membrane permeability, dissipating the proton gradient
Where are uncoupling proteins naturally found →
Brown fat
What common drug can cause uncoupling and hyperthermia →
Aspirin (salicylate) overdose
What toxins inhibit Complex IV of the ETC →
Cyanide, carbon monoxide (CO)
