Respiration

• Aerobic respiration (GCSE level)

  Respiration with oxygen
• Anaerobic respiration (GCSE level)

  Respiration without oxygen
• Properties of ATP that make it a good energy source

  Releases small, manageable amounts of energy so no energy is wasted as heat

  Small, soluble molecule that is easily transported around the cell

  Easily broken down so releases energy instantaneously

  Quickly re-made
• Co-enzymes involved in respiration

  NAD, CoA and FAD

  NAD and FAD transfer hydrogen from one molecule to another

  CoA transfers acetate between molecules
• What is glycolysis

  The splitting of one molecule of glucose into smaller molecules of pyruvate
• Where does glycolysis take place

  Cytoplasm
• In which form of respiration does glycolysis happen

  Both aerobic and anaerobic since it doesn't require oxygen
• Describe the process of glycolysis

  Glucose is phosphorylated by two molecules of ATP

  This produces hexose bisphosphate and two molecules of ATP

  Hexose bisphosphate is unstable so it splits into two molecules of triose phosphate

  Triose phosphate is oxidised to form 2 molecules of pyruvate

  NAD collects the hydrogen ions and turns into 2 reduced NAD (NADH)

  4 ATP are produced (ADP + Pi -> ATP)

  Net gain of 2 ATP
• What is the net gain of ATP in glycolysis

  2
• What are the stages of aerobic respiration

  Glycolysis

  Link reaction

  Krebs cycle

  Oxidative phosphorylation
• Where does the link reaction take place

  The matrix of the mitochondria
• What happens to pyruvate in anaerobic respiration

  Pyruvate is converted into ethanol (in plants and yeast)

  Lactate (in animals and some bacteria) using reduced NAD (NADH)

  This regenerates oxidised NAD so glycolysis can continue to produce small amounts of ATP
• Alcoholic fermentation

  Pyruvate -> (loses a CO2) ethanal (NADH -> NAD) -> ethanol
• Lactate fermentation

  Pyruvate -> (NADH -> NAD) lactate (lactic acid)
• Describe what occurs in the link reaction

  Pyruvate is decarboxylated and a CO2 molecule is released

  Pyruvate is oxidised to form acetate

  NAD is reduced to form reduced NAD (NADH)

  Acetate combines with coenzyme A to form acetyl coenzyme A

  No ATP is produced
• How much ATP is produced in the link reaction


  0
• How many times does the link reaction occur for every glucose molecule

  Twice
• How many times does the Krebs cycle occur for every glucose molecule

  Twice
• What are the products of glycolysis

  2 Net ATP

  2 NADH

  2 Pyruvate
• What are the products of the link reaction for every glucose molecule

  2 Acetyl CoA

  2 CO2

  2 NADH
• What is the NADH from the link reaction used for

  Goes to oxidative phosphorylation