4.7.1 - Intro to respiration

• Respiration

  • Series of reactions that convert chemical energy stored in carbohydrates into ATP
  • Happens in the mitochondria of eukaryotic cells
• Importance of respiration

  • Conversion of energy in bonds of glucose to ATP
  • The equation for respiration is:
  • 6O2 + C6H12O6 → 6CO2 + 6H2O
• Types of respiration

  • There are 2 types of respiration:
  • Aerobic - respiration using oxygen
  • Anaerobic - respiration without oxygen
  • Both types start with glycolysis
• Glycolysis Breakdown

  • Glucose [6C] → Glucose phosphate [6C] (ATP → ADP) → Hexose bisphosphate [6C] (ATP → ADP) → 2x Triose bisphosphate [3C] (4x ADP→ 4x ATP) → 2x Pyruvate [3C]
• Anaerobic respiration

  • Does not use oxygen
  • There are 2 types:
  • Ethanol fermentation - takes place in plants and yeast
  • Lactate fermentation - takes place in animals
• Aerobic respiration

  • Uses oxygen
  • Reaction and products are the same in plants, animals and yeast
  • Aerobic respiration differs to anaerobic respiration in the following ways:
  • Water is produced
  • More ATP is produced
  • Glucose is fully broken down
  • After glycolysis, there is the link reaction, the krebs cycle and oxidative phosphorylation
• Glycolysis

  • First stage of aerobic and anaerobic respiration
  • Occurs in the cytoplasm
  • Aerobic and anaerobic process
• Phosphorylation

  • The first step of glycolysis is the phosphorylation of glucose to glucose phosphate using one molecule of ATP
  • Glucose phosphate is phosphorylated by another molecule of ATP to hexose bisphosphate (6 carbons)
  • Hexose bisphosphate splits into two molecules of TP (3 carbons each)
• Oxidation

  • 2 molecules of TP are oxidised to pyruvate
  • A single molecule produces 2 molecules of ATP and one molecule of NADH
  • In total, the products of glycolysis are 2 ATP and 2 NADH