EXAM FLASHCARDS (BUS VERSION) 🔴 PDC (these are BIG) Q: What does PDC do? A: Pyruvate (3C) → acetyl-CoA (2C) + CO₂ + NADH ⸻ Q: PDC Step 1 A: Decarboxylation of pyruvate to an aldehyde (TPP, E1) ⸻ Q: PDC Step 2 A: Oxidation of aldehyde to carboxylic acid (lipoamide, E2) ⸻ Q: PDC Step 3 A: Formation of acetyl-CoA (transfer to CoA-SH) ⸻ Q: PDC Step 4 A: Reoxidation of lipoamide (FAD → FADH₂) ⸻ Q: PDC Step 5 A: Regeneration of FAD via NAD⁺ → NADH ⸻ Q: PDC inhibitors A: ATP, NADH, acetyl-CoA, fatty acids ⸻ Q: PDC activators A: AMP, CoA, NAD⁺, Ca²⁺ ⸻ 🟠 CAC CORE Q: CAC net products (per acetyl-CoA) A: 2 CO₂, 3 NADH, 1 FADH₂, 1 GTP ⸻ Q: CAC intermediates (order) A: Citrate → Isocitrate → α-KG → Succinyl-CoA → Succinate → Fumarate → Malate → OAA ⸻ Q: CAC enzymes that release CO₂ A: Isocitrate dehydrogenase, α-KG dehydrogenase ⸻ Q: Rate-limiting CAC enzyme A: Isocitrate dehydrogenase ⸻ Q: CAC regulatory enzymes A: Citrate synthase, Isocitrate DH, α-KG DH ⸻ Q: CAC activated by A: ADP, Ca²⁺ ⸻ Q: CAC inhibited by A: ATP, NADH, citrate, succinyl-CoA ⸻ Q: CAC enzyme in ETC A: Succinate dehydrogenase (inner mitochondrial membrane) ⸻ 🟡 NET vs INTERMEDIATE (this prevents mistakes) Q: Is oxaloacetate a net CAC product? A: No — regenerated ⸻ Q: Is citrate a net CAC product? A: No — intermediate ⸻ Q: Why does CAC stop without O₂? A: NADH builds up → NAD⁺ depleted ⸻ 🔵 CARBON LABELING (glycolysis) Q: Glucose C1 & C6 → pyruvate? A: C3 (methyl carbon) ⸻ Q: Glucose C2 & C5 → pyruvate? A: C2 (central carbon) ⸻ Q: Glucose C3 & C4 → pyruvate? A: C1 (carboxylate) ⸻ 🟢 GLYCOGEN (VERY LIGHT) Q: Glycogen phosphorylase product A: Glucose-1-phosphate ⸻ Q: Glycogenesis vs gluconeogenesis A: Glycogenesis = glycogen synthesis Gluconeogenesis = glucose synthesis ⸻ 🟣 PPP (recognition only) Q: PPP purpose A: NADPH + ribose-5-phosphate ⸻ Q: PPP regulation A: NADPH inhibits G6P dehydrogenase

What does PDC do?

Pyruvate (3C) → acetyl-CoA (2C) + CO₂ + NADH

What is PDC Step 1?

Decarboxylation of pyruvate to an aldehyde (TPP, E1)

What is PDC Step 2?

Oxidation of aldehyde to carboxylic acid (lipoamide, E2)

What is PDC Step 3?

Formation of acetyl-CoA (transfer to CoA-SH)

What is PDC Step 4?

Reoxidation of lipoamide (FAD → FADH₂)

What is PDC Step 5?

Regeneration of FAD via NAD⁺ → NADH

What are PDC inhibitors?

ATP, NADH, acetyl-CoA, fatty acids

What are PDC activators?

AMP, CoA, NAD⁺, Ca²⁺

What are the net products of the CAC per acetyl-CoA?

2 CO₂, 3 NADH, 1 FADH₂, 1 GTP

What are the CAC intermediates in order?

Citrate → Isocitrate → α-KG → Succinyl-CoA → Succinate → Fumarate → Malate → OAA

Which CAC enzymes release CO₂?

Isocitrate dehydrogenase, α-KG dehydrogenase

What is the rate-limiting CAC enzyme?

Isocitrate dehydrogenase

Which enzymes are regulatory enzymes in the CAC?

Citrate synthase, Isocitrate DH, α-KG DH

What activates the CAC?

ADP, Ca²⁺

What inhibits the CAC?

ATP, NADH, citrate, succinyl-CoA

Which CAC enzyme is part of the ETC?

Succinate dehydrogenase (inner mitochondrial membrane)

Is oxaloacetate a net CAC product?

No — regenerated

Is citrate a net CAC product?

No — intermediate

Why does the CAC stop without O₂?

NADH builds up → NAD⁺ depleted

What is the result of Glucose C1 & C6 → pyruvate?

C3 (methyl carbon)

What is the result of Glucose C2 & C5 → pyruvate?

C2 (central carbon)

What is the result of Glucose C3 & C4 → pyruvate?

C1 (carboxylate)

What is the product of glycogen phosphorylase?

Glucose-1-phosphate

What is the difference between glycogenesis and gluconeogenesis?

Glycogenesis = glycogen synthesis; Gluconeogenesis = glucose synthesis

What is the purpose of the PPP?

NADPH + ribose-5-phosphate

How is the PPP regulated?

NADPH inhibits G6P dehydrogenase