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Cellular Respiration. Redox Reaction. Redox is an abbreviation for reduction-oxidation reaction Reduction = gain of electrons (hydrogen atom) Oxidation = lose of electrons (hydrogen atom). LEO Goes GER. Oxidation and Reduction reactions are coupled . Reduction or Oxidation?.
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Redox Reaction • Redox is an abbreviation for reduction-oxidation reaction • Reduction = gain of electrons (hydrogen atom) • Oxidation = lose of electrons (hydrogen atom)
LEO Goes GER Oxidation and Reduction reactions are coupled.
Reduction or Oxidation? • NAD+ + H NADH • NADH NAD+ + H • C6H12O6 CO2
Both oxidation and reduction occur during cellular respiration
What “carries” the electron from the glucose to the water? • Electron carriers = coenzyme • NAD+ = coenzyme • Transfers electrons from one molecule to another • Becomes NADH • FAD = coenzyme • Transfers electrons from one molecule to another • Becomes FADH2
What is cellular respiration? • Redox reaction that leads to the step-wise release of energy from glucose to synthesize ATP
Cellular Respiration is also referred to as aerobic respiration • Aerobic = requires oxygen • Anaerobic = does not require oxygen
Which evolved first, aerobic or anaerobic respiration? What supports your decision?
Do you think all of glucose’s energy is transferred to ATP?Does this transfer of energy happen all at once?
Anaerobic Respiration • Glycolysis • Fermentation • Both stages occur in the cytoplasm
Stage 1: Glycolysis 1 Glucose- 6 carbon 2 ATP (donates P) PGAL- 3 C PGAL- 3 C NAD+ NAD+ NADH NADH 2 ADP 2ADP 2 ATP 2ATP Pyruvic Acid- 3 C Pyruvic Acid- 3 C
In glycolysis… • Glucose is oxidized • NAD+ is reduced
Fermentation • Mechanism to re-oxidize NADH, so it can be reused • Does not require oxygen • 2 Types: • Alcoholic • Lactic Acid
Alcoholic Fermentation 2 Pyruvic Acid- 3 C 2 NADH 2 NAD+ 2 Ethyl Alcohol – 2 C + 2 Carbon Dioxide - 1 C
Lactic Acid Fermentation 2 Pyruvic Acid- 3 C 2 NADH 2 NAD+ 2 Lactate – 3 C
In fermentation… • NADH is oxidized • Pyruvic acid is reduced
Cellular (Aerobic) Respiration Equation C6H12O6 + 6O2 6 CO2 + 6 H2O 36 ADP + 36 P 36 ATP
Stages of Aerobic Respiration • Glycolysis • Acetyl CoA production (preparatory reaction) • Krebs citric acid cycle • Electron transport chain & chemiosmosis
Glycolysis (same as anaerobic resp) 1 Glucose- 6 carbon 2 ATP (donates P) PGAL- 3 C PGAL- 3 C NAD+ NAD+ NADH NADH 2ADP 2ADP 2ATP 2ATP Pyruvic Acid- 3 C Pyruvic Acid- 3 C Substrate-level phosphorylation
Acetyl CoA Production • In the matrix of the mitochondria 2 Pyruvic Acid 2 CoA 2NAD+ 2 CO2 2NADH 2 Acetyl CoA Oxidation reaction that prepares carbon compound to enter the Krebs cycle
Krebs Cycle • In matrix of mitochondria • Oxidation of acetyl CoA and reduction of NAD+ • 2 cycles per glucose molecule • Substrate-level phosphorylation
Electron Transport Chain (ETC) • Made up of membrane proteins in the inner membrane (cristae) of mitochondria • Electrons are taken from NADH & FADH2 and passed from protein to protein • This movement of electrons releases energy that allows for formation of H+ concentration gradient
Chemiosmosis/Oxidative phosphorylation • Chemiosmosis = movement of ions down concentration gradient • Chemiosmosis gives energy needed for oxidative phosphorylation.
Each NADH fuels the production of 3 ATP molecules • Each FADH2 fuels the production of 2 ATP molecules