Respiration

• What is the equation for respiration?

  • 6O2 (oxygen)+ C6H12O6 (glucose) → 6CO2 (carbon dioxide)+ 6H2O (water)
• What is phosphorylation?

  The addition of a phosphate group to a molecule.
• Where do the following reactions take place?

  Glycolysis - cytoplasm

  Link reaction - mitochondrial matrix

  Krebs - mitochondrial matrix

  Oxidative phosphorylation - cristae
• Outline the steps in glycolysis


  Glucose --> Glucose phosphate (Phosphorylation)

  Glucose phosphate --> Hexose biphosphate (Phosphorylation)

  Hexose biphosphate --> 2x triose phosphate

  2x Triose phosphate --> 2x pyruvate (Oxidation and reduction)

  • 2x ATP
  • 2X NADH
• What are the types of anaerobic respiration?

  Lactate fermentation - animals

  Ethanol fermentation - plants + animals
• Ethanol fermentation uses what enzyme?

  Pyruvate decarboxylase
• Explain the process of ethanol fermentation


  Pyruvate --> CO2 (catalyzed by pyruvate decarboxylase)

  Ethanal --> Ethanol (reduced)

  • NADH oxidized to NAD
• Explain the process of ethanol fermentation.

  Pyruvate is first converted to ethanal by the enzyme pyruvate decarboxylase.

  • CO2 is produced as a by-product.
  • Ethanal is then reduced to ethanol.
  • This reaction is catalysed by ethanol dehydrogenase.
  • NADH is oxidised to NAD.
• Lactate fermentation process

  Pyruvate → lactate

  • Pyruvate is reduced to lactate.
  • This reaction is catalysed by lactate dehydrogenase.
  • NADH is oxidised to NAD.
• What enzyme catalyzes lactate fermentation?

  Lactate dehydrogenase
• Explain the process of the link reaction

  • Pyruvate diffuses from the cytoplasm across the mitochondrial membrane and into the matrix of the mitochondria.
  • pyruvate --> acetate (decarboxylated and oxidated)
  • CO2 is produced as a by-product.
  • NAD is reduced to NADH.
  • Acetate + coenzyme A (CoA) --> acetyl coenzyme A.
• Outline the steps of the Krebs cycle

  • Acetyl CoA + OAA split to CoA + citrate

  Citrate is:

  • Reduced Reduced​ (NAD)
  • ATP phosphorylation
  • Reduced (FAD)
  • Reduced (NAD) to OAA
• What is OAA?


  Oxaloacetate
• Outline oxidative phosphorylation:

  • Electron Donors: NADH and FADH2 donate electrons to the ETC.
  • ETC Pathway: Electrons pass through complexes I-IV in the inner mitochondrial membrane.
  • Proton Gradient: Energy from electrons pumps protons into the intermembrane space.
  • ATP Synthase: Protons flow back into the matrix, through ATP synthase = ATP
  • Oxygen: Final electron acceptor, forms water to sustain electron flow