respiration

• What are the 4 stages of aerobic respiration?

  • glycolysis (cytoplasm)
  • link reaction (matrix)
  • krebs cycle (matrix)
  • oxidative phosphorylation (inner membrane cristae)
• What happens in glycolysis?

  • 6C glucose is phosphorylated and 2 phosphate groups are added from 2 ATP to form 6C glucose phosphate
  • 6C glucose phosphate is broken down into t lots of 3C TP
  • Each 3C TP is oxidised and forms 3C pyruvate, 2 ATP and NADH from NAD
• what are the products of glycolysis?

  • 2 pyruvate
  • Net gain of 2 ATP
  • 2 NADH
• What happens in the link reaction?


  • 3C pyruvate is oxidised into 2C acetate, this helps make CO2 and NADH from NAD
  • 2C acetate combines with coenzyme A to make 2C Acetylcoenzyme A
• For each glucose molecule, how many link reactions are there?

  • 1 glucose molecule makes 2 pyruvate so there are 2 link reactions
• What happens in the Krebs cycle?

  • 2C acetylcoenzyme A reacts with a 4C compound to make a 6C compound
  • The coenzyme is then released and reused in the link reaction
  • 6C compound then forms 4C compound by producing 2x 1C carbon dioxide, ATP, FADH, 3X NADH
• What happens in oxidative phosphorylation?

  • FADH and NADH are oxidised into NAD and FAD releasing their electrons and protons in the matrix
  • The electrons move along the membrane by a series of redox reactions releasing energy, this is called the electron transport chain
  • Energy from the electron transport chain, actively transports protons from the matrix into the inner membrane space
  • This creates a high electrochemical gradient of protons in the membrane space
  • Protons move by facilitated diffusion back into the matrix through ATP synthase protein
  • ATP synthase will phosphorylate ADP into ATP
  • Oxygen then picks up electrons and protons and forms water
• what is the final electron acceptor?

  • oxygen