Lecture on Aerobic Respiration

Overview

• Aerobic respiration is similar to photosynthesis but in reverse.
• Photosynthesis: Converts water, carbon dioxide, and ATP into glucose and oxygen.
• Respiration: Converts glucose and oxygen into ATP, carbon dioxide, water vapor, and heat.
• Occurs in the mitochondria, not chloroplasts.
• Types of respiration:
  • Aerobic: Requires oxygen, efficient, sustainable, produces more ATP.
  • Anaerobic: Occurs without oxygen, less efficient, produces less ATP.

Cellular Respiration Processes

• Glycolysis:

  • Common to both aerobic and anaerobic respiration.
  • Produces 2 ATP, occurs in the cytoplasm.
  • Breaks down glucose (6 carbons) into 2 pyruvate molecules (3 carbons each).
  • Uses 2 ATP and produces 4 ATP, net gain of 2 ATP.
  • Generates 2 NADH from NAD+.

• Aerobic Pathway:

  • After glycolysis, if oxygen is present, proceeds to aerobic respiration.
  • Involves Prep Steps, Krebs Cycle, and Electron Transport Chain.
  • Prep Steps:
    • Converts 2 pyruvate molecules into 2 acetyl CoA molecules (2 carbons each).
    • Produces 2 carbon dioxide molecules and 2 NADH.
  • Krebs Cycle (to be covered later): Produces additional ATP and electron carriers.
  • Electron Transport Chain (to be covered later): Produces majority of ATP, 34 ATP per glucose.

Anaerobic Pathway

• Happens when oxygen is absent.
• Produces lactic acid or alcohol, depending on organism.
• Does not produce additional ATP beyond the 2 from glycolysis.

Energy Carriers

• ATP: Main energy currency, likened to a battery.
• NADH and FADH2: Electron carriers, store energy in bonds.
• NADPH: Different from NADH, associated with photosynthesis.

Summary of Molecules Produced

• Glycolysis:
  • 2 ATP (net)
  • 4 NADH
  • 0 FADH2 (yet)
• Prep Steps:
  • Conversion to Acetyl CoA.
  • Produces 2 CO2 and 2 NADH.

Next Steps

• Future discussions will cover the Krebs Cycle and the Electron Transport Chain, where significant ATP production occurs.