BIO 120 Cellular Respiration

  1. Anaerobic Respiration
    • when oxygen is not present
    • - ex: Fermentation
  2. Fermentation
    • occurs instead of cellular respiration
    • incomplete oxidation (giving less ATP)
    • waste products: CO2 and lactic acid or ethanol
    • produces 2 ATP
  3. Aerobic Respiration
    • when oxygen is present
    • consumes organic molecules and O2 and yields ATP
    • C6H12O6 + 6O2 --> 6CO2 + 6H2O + Energy
  4. Oxidative Phosphorylation
    • making ATP via electron transport chain by adding Phosphate
    • requires oxygen and electron transport chain
    • ex: in photosynthesis b/t photosystem II and I
  5. Substrate Level Phosphorylation
    • making ATP from a substrate
    • no electron transport chain
    • no oxygen
    • less ATP made
  6. NAD+
    • coenzyme; electron acceptor
    • passes electrons to electron transport chain
    • NADH = reduced form of NAD+
  7. Glycolysis
    • First phase of aerobic respiration
    • Breaks down glucose into two molecules of pyruvate
    • Takes place outside of mitochondria, in cytosol
    • Makes 2 pyruvates, 2 NADH, and 4 ATP by substrate-level phosphorylation
    • Uses glucose and 2 ATP
  8. Citric Acid (Kreb's) Cycle
    • completes the breakdown of glucose
    • Gain 1 ATP per cycle - 2 pyruvates formed during glycolysis, so must go around cycle 2 times = 2 ATP (by substrate-phosphorylation)
    • in mitochondria region
    • more electrons added from glycolysis
  9. Kreb's Cycle (cont.)
    • releases a TOTAL of:
    • 4 CO2 (other 2 CO2 needed for product comes from the change into pyruvate)
    • 2 ATP
    • 6 NADH
    • 2 FADH2
    • 1 molecule pyruvate releases:
    • 2 CO2
    • 1 ATP
    • 3 NADH
    • 1 FADH2
  10. Electron Transport Chain
    • Following glycolysis and the citric acid cycle, NADH and FADH2 account for most of the energy extracted from food
    • These 2 e- carriers donate e-s to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation
    • slow release of a little energy at a time; controlled
  11. Electron Transport Chain (cont.)
    • Electrons are passed through a number of cytochromes (proteins with iron atom that accept and donate electrons) to O2
    • Function: to break the large free-energy drop from food to O2 into smaller steps that release energy in manageable amounts
    • Releases 32-34 ATP
  12. Chemiosmosis
    • use of energy in H+ gradient to drive cellular work
    • Electron transfer causes proteins to pump H+ from the mitochondrial matrix to the intermembrane space
    • H+ moves back across the membrane through channels in ATP synthase
  13. Fermentation and anaerobic respiration
    • Glycolysis can produce ATP with or without O2
    • Anaerobic respiration uses electron transport chain with electron acceptor other than O2
    • Fermentation uses phosphorylation instead of electron transport chain
  14. Why do fermentation?
    • To get rid of pyruvate - waste product can get out of the cell
    • Continue making ATP & NADH from glycolysis
  15. Fermentation and Aerobic Respiration
    • Both use glycolysis
    • Different final electron acceptors
    • Different amounts of ATP produced (Aerobic = 38 ATP per glucose molecule; Fermentation = 2 ATP per glucose molecule)
  16. Why is Oxygen needed?
    • It is the final electron acceptor in electron transport chain
    • For pull of pyruvate into mitochondria (changing to CoA)
Card Set
BIO 120 Cellular Respiration
Vocab to know for a biology exam covering cellular respiration