Respiration Lecture Notes

Overview

• Definition of respiration
• Usage of energy by organisms
• Types of respiration: aerobic and anaerobic

What is Respiration?

• Cellular respiration: an exothermic reaction transferring energy from glucose.
• Occurs continuously in living cells.
• Breaks down glucose to release trapped energy.
• Energy is transferred, not created.

How Organisms Use Energy

1. Building Molecules
   • E.g., combining amino acids to form proteins.
2. Muscular Contraction
   • Enables movement of limbs.
3. Maintaining Body Temperature
   • Keeps organisms warm in colder environments.

Types of Respiration

Aerobic Respiration

• Most common form of respiration.
• Requires oxygen; most efficient method.
• Occurs continuously in plants and animals.
• Takes place in mitochondria.
• Equation:
  • Word: Glucose + Oxygen → Carbon Dioxide + Water
  • Chemical: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Anaerobic Respiration

• Occurs without oxygen.
• Used when oxygen supply is insufficient, e.g., during sprinting.
• Equation in Humans:
  • Word: Glucose → Lactic Acid
• Limitations:
  • Inefficient energy release due to partial glucose breakdown.
  • Produces lactic acid, which is toxic and must be removed.

Anaerobic Respiration in Plants and Yeast

• Equation:
  • Word: Glucose → Ethanol + Carbon Dioxide
• Known as fermentation in yeast.
• Industrial applications:
  • Bread making: CO₂ creates air pockets, making bread light and fluffy.
  • Alcohol production: Ethanol is used to make beer and wine.

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