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Glucose CatabolismRespiratory Chain
• Respiration: a process changes reducing power into a biological useful energy form ATP.
– Aerobic respiration: oxygen is the final electron acceptor, the product is H2O.
– Anaerobic respiration: the final electron acceptors are other than oxygen such as NO3
-, SO42-, Cu2+, and Fe3+.
• Respiratory chain is the electron transport chain for formation of ATP by transferring electrons from the carriers such as NADH to an electron acceptor.
Glucose CatabolismRespiratory Chain-Oxidative Phosphorylation
“Oxidative Phosphorylation is the electron transport chain that forms ATP as electrons are transferred from NADH or FADH2 to oxygen by a series of electron carriers” (L. Stryer, 1988)
- electron acceptor: oxygen (aerobic condition)- generate ATP, H2O- from NADH or FADH2
Taking place in mitochondria in eucaryotesor in cytoplasmic membrane in procaryotes
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/oxidative/oxidativephosphorylation.html
Glucose CatabolismOxidative Phosphorylation
• In the process of Oxidative Phosphorylation
In eucaryotes:
NADH + H+ 3 ATP
FADH2 2 ATP
In procaryotes:
NADH + H+ ≤2 ATP
FADH2 ATP
Glucose Aerobic CatabolismReaction Summary
• EMP (glycolysis)Glucose + 2ADP + 2 NAD+ + 2 Pi →2 pyruvate + 2 ATP+ 2 (NADH + H+)
• Entry of pyruvate2pyruvate + 2NAD+ + 2CoA-SH →2 acetyl-CoA + 2CO2 + 2(NADH + H+)
• TCA cycle2acetyl-CoA + 6 NAD + 2FAD + 2GDP+ 2Pi + 4H2O → 2CoA + 6(NADH
+ H+) +2FADH2+2GTP (~ATP) + 4CO2
• Oxidative Phosphorylation In eucaryotes
EMP: 2 NADH → 2 FADH2 → 4 ATP (glycerol phosphate shuttle)Entry of pyruvate and TCA: 8 NADH → 24 ATPTCA: 2FADH2 → 4 ATP
The overall reaction:Glucose + 6O2 + 36ADP + 36 Pi → 6 CO2 + 6 H2O + 36 ATP
http://www.metabolic-database.com/html/body_lipogenesis__prevention_of_fat1.html
Glucose Catabolism
Glucose
Aerobic metabolism Anaerobic metabolism
Tricarboxylic acid (TCA)or (Krebs)or (Citric acid cycle)
Respiratory chain:Oxidative phosphorylation
Glycolysis orEmbden-Meyerhof-Parnas (EMP)
Fermentation: ethanol, acetic acid, lactate.
Glucose Anaerobic CatabolismGlycolysis (EMP)
Ethanol Production
Glycolysis (EMP)
Fermentation
Pyruvate
Decarboxylase
Alcohol dehydrogenase
Hydrocarbon Catabolism• Hydrocarbon: C & H
- Aliaphatic hydrocarbon
e.g. octane, C8H18
polyethylene –HC=CH-- Aromatic hydrocarbon
naphthalene
• Metabolism of hydrocarbon- Requires oxygen- Hydrocarbons are converted to acetyl-CoA which is metabolized by TCA cycle.- Challenges : low solubility in aqueous solution.
available microorganisms are limitedPseudomonas, Mycobacteria
naphthalene
http://umbbd.ahc.umn.edu/naph/naph_image_map.html
http://umbbd.ahc.umn.edu/naph/naph_map.html
http://www.dcs.napier.ac.uk/~cs203/catech.html
Naphthalene Pathway
Nitrogen Compounds CatabolismNitrogen compounds can be used for C, N and energy
sources
Proteins → peptides → amino acids → converted other amino acids or organic acids and ammonia by deamination.
- organic acids: acetyl-CoA into TCA cycle, lipids- amino acids: proteins, other amino acids or enter
TCA cycle- ammonium: amino acid, protein, nucleic acids
Nucleic acids → ribose/deoxyribose, phosphoric acid and purine/pyrimidine
- sugar: glycolysis and TCA- Phosphoric acid: ATP, lipids, nucleic acids- bases: nucleic acids, urea, acetic acids
Photosynthesis
Glycolysis and TCA
Overview of Biosynthesis• Pentose-phosphate pathway (hexo-
monophosphate pathway (HMP):
convert glucose-6-phosphate into carbon skeletons of C3 ~ C7 .
• Polysaccharides: glycan, glycogen
gluconeogenesis
• Lipids
• Proteins
• Nucleic acids (DNAs, RNAs)
1
4
5
2
6
3
Summary of Metabolism Pathways• Metabolism:
- catabolism: ATP, C skeleton for further biosynthesis- anabolism: biosynthesis requiring energy
• Bioenergetics: - energy storage and carrier ATP - Reducing power carriers: NADH, NADPH, FADH2
• Glucose catabolism:
Summary of Metabolism Pathways• Glucose catabolism:
Glucose
Anaerobic metabolism
Tricarboxylic acid (TCA)or (Krebs)or (Citric acid cycle)
Respiratory chain:Oxidative phosphorylation
Glycolysis orEmbden-Meyerhof-Parnas (EMP)
Fermentation: ethanol, acetic acid, lactate.
Aerobic metabolism
Summary of Metabolism Pathways
- Under aerobic condition, one molecule of Glucose catabolism generates:
in Glycolysis, 2 ATP, 2 NADH and 2 pyruvate
in TCA cycle, 6 (NADH+H+), 2FADH2, 2GTP, and 4CO2
in oxidative phosphorylation:
NADH, FADH2, O2→ ATP, H2O
Summary of Metabolism Pathways
- Under anaerobic condition, Glucose catabolism includes Glycolysis and fermentation:
Products: ethanol, lactic acid, ATP, etc.
• Nitrogen compound catabolism
• Hydrocarbon catabolism
• Photosynthesis
• Biosynthesis