Cell Respiration Overview

Overview of Cell Respiration

• Cell respiration is the process by which cells generate energy from glucose
• It involves the breakdown of glucose and other organic molecules to produce ATP (adenosine triphosphate)
• ATP is the primary energy currency of the cell

Stages of Cell Respiration

1. Glycolysis
   • Takes place in the cytosol
   • Breaks down glucose into pyruvate, producing 2 ATP and 2 NADH
   • Net gain of 2 ATP
2. Pyruvate Oxidation
   • Takes place in the mitochondria
   • Converts pyruvate into acetyl-CoA, producing 2 NADH and 2 ATP
3. Citric Acid Cycle (Krebs Cycle)
   • Takes place in the mitochondrial matrix
   • Converts acetyl-CoA into ATP, NADH, and FADH2
   • Produces 2 ATP, 6 NADH, and 2 FADH2
4. Electron Transport Chain
   • Takes place in the mitochondrial inner membrane
   • Uses energy from NADH and FADH2 to pump protons across the membrane
   • Produces ATP through chemiosmosis
5. Oxidative Phosphorylation
   • Takes place in the mitochondrial inner membrane
   • Uses energy from the electron transport chain to produce ATP

ATP Yield

• Total ATP yield from complete breakdown of one glucose molecule: 36-38 ATP
• Net gain from glycolysis: 2 ATP
• Net gain from pyruvate oxidation, citric acid cycle, and oxidative phosphorylation: 34-36 ATP

Regulation of Cell Respiration

• Feedback inhibition: ATP and NADH inhibit key enzymes in glycolysis and the citric acid cycle
• Allosteric regulation: ATP and ADP bind to enzymes to regulate activity
• Hormonal regulation: insulin and glucagon regulate glucose metabolism

Cell Respiration Overview

• Cell respiration generates energy from glucose and organic molecules, producing ATP
• ATP is the primary energy currency of the cell

Stages of Cell Respiration

Glycolysis

• Breaks down glucose into pyruvate, producing 2 ATP and 2 NADH in the cytosol
• Net gain of 2 ATP

Pyruvate Oxidation

• Converts pyruvate into acetyl-CoA, producing 2 NADH and 2 ATP in the mitochondria

Citric Acid Cycle (Krebs Cycle)

• Converts acetyl-CoA into ATP, NADH, and FADH2 in the mitochondrial matrix
• Produces 2 ATP, 6 NADH, and 2 FADH2

Electron Transport Chain

• Uses energy from NADH and FADH2 to pump protons across the mitochondrial inner membrane
• Produces ATP through chemiosmosis

Oxidative Phosphorylation

• Uses energy from the electron transport chain to produce ATP in the mitochondrial inner membrane

ATP Yield

• Total ATP yield from complete breakdown of one glucose molecule: 36-38 ATP
• Net gain from glycolysis: 2 ATP
• Net gain from pyruvate oxidation, citric acid cycle, and oxidative phosphorylation: 34-36 ATP

Regulation of Cell Respiration

• Feedback inhibition: ATP and NADH inhibit key enzymes in glycolysis and the citric acid cycle
• Allosteric regulation: ATP and ADP bind to enzymes to regulate activity
• Hormonal regulation: insulin and glucagon regulate glucose metabolism