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Cellular Respiration :Cellular Respiration BIOLOGY
Cellular Respiration :Cellular Respiration Aerobic (requires oxygen)
A cellular process that requires oxygen and gives off carbon dioxide.
Most often involves breaking down glucose to make CO2, H2O, and ATP.
Glycolysis :Glycolysis Occurs in cytosol.
Energy within a glucose is released slowly.
Costs 2 ATP to start. (-2)
Makes 4 ATP. (+4)
Net gain of 2 ATP. (=2)
Reactants – glucose
Products – pyruvic acid, NADH & ATP
The Krebs cycle :The Krebs cycle Reactants – Pyruvate, NAD+, FAD Has 8 steps with 8 different enzymes. Products – 2 ATP, NADH, FADH2 Occurs in matrix of mitochondria
Electron Transport System :Electron Transport System As electrons pass down the electron transport system, energy is captured and ATP is produced.
The total of 32-34 ATP produced by ETS is calculated by allowing 3 ATP per NADH and 2 ATP per FADH2 that enter the ETS.
Occurs on the inner membrane folds of mitochondria
Figure 9.5 An introduction to electron transport chains :Figure 9.5 An introduction to electron transport chains
Chemiosmosis couples the electron transport chain to ATP synthesis :Chemiosmosis couples the electron transport chain to ATP synthesis Yellow arrow = electron flow
Red arrow = proton flow to form ATP
Figure 9.14 ATP synthase, a molecular mill :Figure 9.14 ATP synthase, a molecular mill
Slide 9:Cellular Respiration Summary
Fermentation :Fermentation Glycolysis followed by reduction of pyruvate to either lactate or alcohol & CO2
Anaerobic
(no oxygen)
Can provide
rapid burst of
ATP.
Yields only 2 ATP
Fermentation :Fermentation Alcohol--yeast produce wine and beer and
cause bread to rise.
Lactic Acid—bacteria produce yogurt, sauerkraut, cheese. Also in muscle cells when working anaerobically.
Comparison of Cellular Respiration versus Fermentation :Comparison of Cellular Respiration versus Fermentation One mole of glucose yields 686 kcal.
Cellular respiration - 263/686 = 38% of available energy is used.
Fermentation - 15/686 or 2% of available energy.
The Formulas :The Formulas Cellular Respiration
6O2 + C6H12O6 ? 6CO2 + 6H2O + energy
Long term, continuous use of energy
Lactic Acid Fermentation
pyruvic acid + NADH ? lactic acid + NAD+
Short spurts of energy in emergency situations then muscle fatigue and cramps
Alcoholic Fermentation
pyruvic acid + NADh ? alcohol + CO2 + NAD+