Biology: Cellular Respiration

Overview of Respiration

• Respiration is the process by which cells generate energy from the food they consume
• It involves the breakdown of glucose and other organic molecules to produce ATP (adenosine triphosphate)

Types of Respiration

• Aerobic Respiration: occurs in the presence of oxygen, produces a net gain of 36-38 ATP molecules per glucose molecule
  • Takes place in the mitochondria
  • Involves three stages: glycolysis, citric acid cycle, and oxidative phosphorylation
• Anaerobic Respiration: occurs in the absence of oxygen, produces a net gain of 2 ATP molecules per glucose molecule
  • Takes place in the cytoplasm
  • Involves two stages: glycolysis and fermentation

Stages of Aerobic Respiration

• Glycolysis: breakdown of glucose into pyruvate, producing 2 ATP and 2 NADH molecules
  • Takes place in the cytoplasm
  • Net gain of 2 ATP molecules
• Citric Acid Cycle (Krebs Cycle): breakdown of pyruvate into acetyl-CoA, producing 2 ATP, 6 NADH, and 2 FADH2 molecules
  • Takes place in the mitochondria
  • Net gain of 2 ATP molecules
• Oxidative Phosphorylation: production of ATP molecules using the energy from NADH and FADH2 molecules
  • Takes place in the mitochondrial inner membrane
  • Net gain of 32-34 ATP molecules

Respiratory Quotient (RQ)

• RQ is the ratio of CO2 produced to O2 consumed during respiration
• RQ values:
  • Carbohydrates: 1
  • Fats: 0.7
  • Proteins: 0.8

Importance of Respiration

• Generating energy for cellular activities
• Maintaining cellular homeostasis
• Supporting growth and development

Respiration Overview

• Respiration is the process of generating energy from consumed food by breaking down glucose and organic molecules to produce ATP.

Aerobic Respiration

• Occurs in the presence of oxygen, producing a net gain of 36-38 ATP molecules per glucose molecule.
• Takes place in the mitochondria.
• Involves three stages: glycolysis, citric acid cycle, and oxidative phosphorylation.

Anaerobic Respiration

• Occurs in the absence of oxygen, producing a net gain of 2 ATP molecules per glucose molecule.
• Takes place in the cytoplasm.
• Involves two stages: glycolysis and fermentation.

Glycolysis

• Breakdown of glucose into pyruvate, producing 2 ATP and 2 NADH molecules.
• Takes place in the cytoplasm.
• Net gain of 2 ATP molecules.

Citric Acid Cycle (Krebs Cycle)

• Breakdown of pyruvate into acetyl-CoA, producing 2 ATP, 6 NADH, and 2 FADH2 molecules.
• Takes place in the mitochondria.
• Net gain of 2 ATP molecules.

Oxidative Phosphorylation

• Production of ATP molecules using energy from NADH and FADH2 molecules.
• Takes place in the mitochondrial inner membrane.
• Net gain of 32-34 ATP molecules.

Respiratory Quotient (RQ)

• Ratio of CO2 produced to O2 consumed during respiration.
• RQ values: carbohydrates (1), fats (0.7), and proteins (0.8).

Importance of Respiration

• Generating energy for cellular activities.
• Maintaining cellular homeostasis.
• Supporting growth and development.