Biology

• What are the four key stages of respiration mentioned in the study material?

  Glycolysis, link reaction, Krebs cycle, and oxidative phosphorylation
• Where does glycolysis occur in the cell?


  In the cytoplasm
• What is the net gain of ATP from glycolysis?

  2 ATP
• What is the first step in glycolysis?

  Glucose is phosphorylated to glucose phosphate
• How many ATP molecules are used in the phosphorylation of glucose during glycolysis?

  2 ATP molecules
• What is produced when triose phosphate is oxidized in glycolysis?

  Pyruvate, 4 ATP, and reduced NAD
• What is the role of NAD in glycolysis?

  NAD acts as a coenzyme that picks up hydrogen to form reduced NAD
• What happens to pyruvate after glycolysis in aerobic respiration?

  It is actively transported into the mitochondrial matrix for the link reaction
• What is produced during the link reaction from pyruvate?

  Acetate, carbon dioxide, and reduced NAD
• What does acetate combine with to enter the Krebs cycle?

  Coenzyme A
• How many times does the link reaction occur for each glucose molecule?

  Twice
• What are the products of one cycle of the Krebs cycle?

  3 reduced NAD, 1 reduced FAD, 1 ATP, and 2 carbon dioxide
• How does the Krebs cycle differ in terms of products when considering one glucose molecule?

  The cycle produces double the products because it occurs twice for each glucose molecule
• What is the final step of respiration called?

  Oxidative phosphorylation
• What is the role of oxygen in oxidative phosphorylation?

  Oxygen acts as the final electron acceptor and forms water
• How many ATP molecules are produced during oxidative phosphorylation?

  34 ATP molecules
• What is the purpose of anaerobic respiration?

  To re-oxidize NAD so that glycolysis can continue
• What are the end products of anaerobic respiration in animals?

  Lactate or lactic acid
• What happens to pyruvate in anaerobic respiration?

  It is reduced to form lactate
• What is a downside of lactic acid production in anaerobic respiration?

  Lactic acid can denature enzymes and other proteins
• What do microbes produce during anaerobic respiration?

  Ethanol and carbon dioxide
• Why is ethanol production in microbes considered harmful?

  Because ethanol can be toxic to the organism
• What are the key stages of aerobic respiration and their locations?

  • Glycolysis: Cytoplasm
  • Link Reaction: Mitochondrial Matrix
  • Krebs Cycle: Mitochondrial Matrix
  • Oxidative Phosphorylation: Mitochondrial Matrix
• What are the products of glycolysis and their significance?

  • 2 Pyruvate: Needed for the link reaction
  • 2 ATP: Net gain for energy
  • 2 Reduced NAD: Used in further stages of respiration
• What are the products of the Krebs cycle per glucose molecule?

  • 6 Reduced NAD
  • 2 Reduced FAD
  • 2 ATP
  • 4 Carbon Dioxide
• What is the process of oxidative phosphorylation?

  1. Reduced coenzymes release hydrogen
  2. Electrons are transported along the electron transfer chain
  3. Protons are actively transported, creating a gradient
  4. Protons move through ATP synthase to produce ATP
  5. Oxygen acts as the final electron acceptor, forming water
• What are the differences between aerobic and anaerobic respiration?

  • Aerobic Respiration:
  • Requires oxygen
  • Produces more ATP
  • Occurs in mitochondria
  • Anaerobic Respiration:
  • Does not require oxygen
  • Produces less ATP
  • Occurs in cytoplasm