chap 6

Glycolysis

• ATP Yield During Glycolysis

  • Starts with: 1 glucose molecule

  • Consumes: 2 ATP

  • Produces: 4 ATP

  • Net gain: 2 ATP

• Transformation of Pyruvate to Acetyl CoA

  • Pyruvate is formed from glycolysis

  • Each pyruvate is converted to acetyl CoA, producing:

    • 1CO₂ per pyruvate

    • NADH per pyruvate

  • Occurs in mitochondria

  • Result: 2 acetyl CoA from 2 pyruvates

Krebs Cycle (Citric Acid Cycle)

• Occurs in the mitochondria (matrix)

• Each turn produces:

  • 2 CO₂

  • 1 ATP (or equivalent)

  • 3 NADH

  • 1 FADH2

• Total per glucose (2 turns):

  • 4 CO₂

  • 2 ATP

  • 6 NADH

  • 2 FADH2

Electron Transport Chain (ETC)

• Takes place in the inner mitochondrial membrane

• Oxygen acts as the final electron acceptor

• NADH and FADH2 donate electrons to the chain

• Creates a hydrogen ion gradient used for ATP production through chemiosmosis

Chemiosmosis

• Process where hydrogen ions flow back into the mitochondrial matrix via ATP synthase

• Drives the formation of ATP from ADP + Pi

ATP Yield from Glucose Catabolism

• Glycolysis: 2 ATP (net gain)

• Pyruvate Entering Acetyl CoA: 0 ATP

• Krebs Cycle: 2 ATP

• Electron Transport Chain: 28 ATP

• Total ATP: Approx. 32 ATP per glucose

Mitochondrial Disease

• Genetic disorders affecting metabolism

• Symptoms: muscle weakness, loss of coordination, neurological issues

• Treatment requires specialized training in medical genetics

Oxidative Phosphorylation Overview

• Begins with the electron transport chain

• Electrons released energy used to pump hydrogen ions, forming a gradient

• ATP produced through ATP synthase via chemiosmosis

Key Terms

• Aerobic Respiration: Cellular respiration requiring oxygen

• Anaerobic Respiration: Occurs when oxygen is absent

• Fermentation: Pathway to regenerate NAD+ in the absence of oxygen

• Substrate-level phosphorylation: Direct production of ATP by transferring a phosphate group

• Oxidative phosphorylation: Production of ATP using the electron transport chain and chemiosmosis.