Overview
This lecture explains cellular respiration, its importance for living organisms, and the differences between aerobic and anaerobic respiration, including their equations and applications.
What is Respiration?
- Respiration is the process cells use to transfer energy from glucose.
- Described as an exothermic reaction, it releases energy continuously in living cells.
- Energy is not created; it is transferred from glucose molecules.
Uses of Respiration Energy
- Energy is used to build large molecules from smaller ones (e.g., amino acids to proteins).
- Required for muscular contraction to move limbs.
- Helps maintain body temperature in various environments.
- Needed for many other vital body reactions.
Types of Respiration
- Two main types: aerobic respiration and anaerobic respiration.
Aerobic Respiration
- Occurs in the presence of sufficient oxygen.
- Most efficient way to transfer energy from glucose.
- Takes place in mitochondria of both plant and animal cells.
- Word equation: Glucose + Oxygen → Carbon Dioxide + Water.
- Chemical equation: C6H12O6 + 6O2 → 6CO2 + 6H2O.
Anaerobic Respiration in Humans
- Occurs when oxygen is scarce, such as during intense exercise.
- Word equation: Glucose → Lactic Acid.
- Less efficient, as glucose is only partially broken down.
- Produces lactic acid, which is toxic and must be removed from the body.
Anaerobic Respiration in Plants and Yeast
- Word equation: Glucose → Ethanol + Carbon Dioxide.
- In yeast, this process is called fermentation.
- Fermentation is used in bread-making (CO2 forms air pockets) and alcohol production (ethanol for beer and wine).
Key Terms & Definitions
- Respiration — The process of transferring energy from glucose in living cells.
- Exothermic Reaction — A reaction that releases energy.
- Aerobic Respiration — Respiration using oxygen, occurring in mitochondria.
- Anaerobic Respiration — Respiration without oxygen, producing less energy.
- Lactic Acid — A toxic by-product of anaerobic respiration in humans.
- Fermentation — Anaerobic respiration in yeast, producing ethanol and carbon dioxide.
Action Items / Next Steps
- Review word and chemical equations for both types of respiration.
- Practice explaining the differences between aerobic and anaerobic respiration.