chapter 6 iv. glycolysis and aerobic respiration...iv. glycolysis and aerobic respiration c 6h 12o 6...
TRANSCRIPT
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Chapter 6
IV. Glycolysis and AerobicRespiration
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
Energy flowand chemicalrecycling in
theecosystem.
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Mitochondrion Structure
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
Aerobic Respiration
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Overview
• Respiration – Extracting stored energyfrom glucose to form ATP.
• The breakdown of glucose occurs intwo stages.– Glycolysis (does not require oxygen)– Aerobic Respiration (Requires Oxygen)
• Preparatory step• Krebs Cycle (Citric Acid Cycle)• Electron Transport Chain
Energy Storing Compounds
• ADP + Pi ATP• NAD+ + 2e- + H+ NADH• FAD+ + 2e- + 2H+ FADH• Reduction = The addition of electrons.
– NAD+ + 2e- + H+ NADH• Oxidation = The removal of electrons
from a compound.– NADH NAD+ + 2e-
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Glycolysis
• Glycolysis – Glucose breaking downthrough the action of enzymes.
• Occurs in the cytoplasm of the cell.• Glycolysis does not require oxygen• Substrate-level phosphorylation =
The formation of ATP during glycolysisand the krebs cycle.
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Glycolysis - Summary
• 2ATP are used to “kick start” thereaction.
• 4 ADP are converted to 4 ATP viasubstrate level phosphorylation.
• 2 NAD+ are reduced to 2NADH.• 2 Pyruvate are produced
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Aerobic Respiration
• Occurs in themitochondrion.
• Three stages– Preparatory step– Krebs Cycle (Citric acid
cycle)– Electron Transport
Chain
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Aerobic Respiration – PreparatorySteps
• Pyruvate is converted to acetyl-CoA• NAD+ is reduced to NADH• CO2 is released.• Remember there are two pyruvate
molecules! So this reaction happens foreach pyruvate molecule!
Aerobic Respiration – Krebs Cycle(Citric acid cycle)
Named after Hans Kreb (1930s) The first compound created is citrate (citric
acid cycle) 3NAD+ are reduced to 3NADH. FAD+ is reduced to FADH2 1 ATP is created via substrate level
phosphorylation. 2CO2 are released. Remember that there are two acetyl-CoA!
This reaction occurs for each acetyl-CoA!
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Record Keeping – What wehave so far.
1 ATP x 2 = 2ATP1 FADH2 x 2 = 2 FADH2
3 NADH x 2 = 6NADHKrebs Cycle
1 NADH x 2 = 2NADHPreparatory steps
2 ATP (Net)2 NADHGlycolysis
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Aerobic Respiration - ElectronTransport Chain
• Occurs at the inner mitochondrial membrane.• This is the stage where most of the ATP is
made!• NADH and FADH2 are oxidized to NAD+ and
FAD+
• Electrons are released into the electrontransport chain.
• H+ is pumped into the intermembane spacecreating a concentration gradient.
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Aerobic Respiration - ElectronTransport Chain
• H+ passes back into the mitochondrialmatrix through ATP synthases whichgenerate ATP from ADP.
• Oxidative phosphorylation – Theformation of ATP as a result of theelectron transport chain.
Aerobic Respiration - ElectronTransport Chain
• Oxygen is the final electron acceptor!• Oxygen combines with 2H+ and two
electrons to form H2O!• Oxygen keeps the electrons moving
through the chain! Without oxygenthe electron transport chain wouldstop! No ATP would be generated!
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Other Sources of Energy
• Fats and Proteins can be used forenergy.
• A gram of fat provides twice as muchATP as a gram of glucose.
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