Lecture Notes: Grade 11 Life Science – Cellular Respiration

Introduction

• Instructor: Luellen
• Topic: Cellular Respiration
• Special Segment: Announcement about a fundraiser for a student with leukemia; fundraising involved shaving heads.
• Additional Note: Special session for Grade 12 from 7 to 7:30 PM related to the movie 'After Earth'.

Overview of Cellular Respiration

• Cellular respiration involves converting food into energy.
• Key Concept: Glucose is essential for energy production.

Key Definitions

• Aerobic Respiration: Requires oxygen to produce energy.
• Glycolysis: Initial stage of cellular respiration where glucose is broken down.
• Krebs Cycle (Citric Acid Cycle): Further breakdown of molecules to produce energy.
• Oxidative Phosphorylation: Final stage of aerobic respiration, where most ATP is produced.

Aerobic vs Anaerobic Respiration

• Aerobic Respiration: Involves oxygen, produces a significant amount of ATP (38 ATPs).
• Anaerobic Respiration: Does not require oxygen, produces less ATP (2 ATPs).

Detailed Stages of Aerobic Respiration

1. Glycolysis

• Occurs in the cytoplasm.
• Inputs: Glucose (C6H12O6)
• Outputs: 2 Pyruvic Acids, 2 ATP, 2 NADH
• **Process: **
  • Glucose is broken down into 2 molecules of 3-carbon pyruvic acid.
  • Produces 2 ATP and 2 NADH.

2. Krebs Cycle

• Occurs in the mitochondria.
• Inputs: Pyruvic Acid
• Outputs: 6 NADH, 2 FADH2, 2 ATP, 4 CO2
• **Process: **
  • Pyruvic acid is converted to Acetyl-CoA before entering the cycle.
  • Releases CO2 as a byproduct.
  • Produces 6 NADH, 2 FADH2, 2 ATP per glucose molecule (considering two pyruvic acids).

3. Oxidative Phosphorylation (Electron Transport Chain)

• Also occurs in the mitochondria.
• Inputs: NADH, FADH2
• Outputs: 34 ATP, Water
• **Process: **
  • Electrons from NADH and FADH2 are transferred through protein complexes.
  • Oxygen is the final electron acceptor, forming water.
  • Generates a large amount of ATP (34 ATP from one glucose molecule).

Anaerobic Processes

• Fermentation: Converts pyruvic acid into lactic acid or alcohol, allowing glycolysis to continue generating ATP without oxygen.
• Lactic Acid Fermentation: Occurs in muscles during strenuous activity.
• Alcohol Fermentation: Used in industries for alcohol production.

Practical Applications

• Importance of understanding cellular respiration in biological and industrial processes.

Conclusion

• Total ATP from Aerobic Respiration: 38 ATP
• Importance of Oxygen for efficient energy production.
• Encouragement to understand the application of these processes in everyday life and industries.

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Additional Information

• Code Word for Competition: Fossils
• Upcoming Event: Join the After Earth special today from 7 to 7:30 PM.
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