360 likes | 841 Views
Microbial Metabolism. Microbial Metabolism. The sum of all chemical reactions within a living organism Catabolism Anabolism. Catabolism. Destructive metabolism ; the breaking down in living organisms of more complex substances into simpler ones, with the release of energy
E N D
Microbial Metabolism • The sum of all chemical reactions within a living organism • Catabolism • Anabolism
Catabolism Destructive metabolism; the breaking down in living organisms of more complex substances into simpler ones, with the release of energy (opposed to anabolism)
CO2 + H2O + Energy Catabolism • Complex substances into simple ones, releases energy Glucose
Catabolism Peptide Single amino acids Protein Energy
Anabolism Constructive metabolism; the synthesis in living organisms of more complex substances from simpler ones, spending energy (opposed to catabolism )
Amino acids + Energy Proteins Anabolism • Simple substances into complex ones, spend energy
Anabolism Peptide Enzyme Energy Single amino acids Protein
Enzymes • Speed up chemical reactions • Increase frequency of collision • Orient molecules • Lower activation energy • Low temperatures
Enzymes (cont.) • Very efficient • Reactions occur 10 billion times faster than without enzyme • Enzyme does not change during reaction
Substrate • Substance that the enzyme acts on (i.e.. Sucrose) sucrose + sucrase=glucose & fructose substrate+enzyme=product(s)
Enzyme structure • three-dimensional shape (thousands of shapes) • lock and key complementary
Enzyme structure Substrate Product Processing Enzyme Active site
Turnover number • Maximum number of substrate molecules that one enzyme can process per second • 1 to 10,000, but may be as high as 500,000
Enzyme cellular control • Repression • Induction
Repression • Mechanism that inhibits the synthesis of an enzyme when the specific-end product is present in abundance, or the substrateis absent
Induction • Mechanism that promotes the synthesis of an enzyme when the specific-end product is present in low concentration, or absent, and the substrateis present
Repression/induction Lactose present B-galactosidase Glucose and galactose (end products) high concentration
End-product and enzyme b-galactosidase (enzyme) Glucose and galactose (end products) Concentration Time
Substrate and enzyme B-galactosidase Lactose (substrate) Concentration Time
Substrate and enzyme B-galactosidase Lactose (substrate) Concentration Time
Cofactors • Metal ions (Fe, Cu, Mg, Zn, Ca and Co) • Bridge between substrate and enzyme • Coenzymes • Derived from vitamins (B-vitamins) • Electron carriers (NAD+ & NADP+)
Factors Influencing Enzymatic Activity • Temperature • pH • Inhibitors • Cyanide, arsenic, mercury
Energy Production • Adenosine triphosphate (ATP) • Cell’s energy carrier • Mitochondria (eucaryotes) • Plasma membrane (bacteria)
Respiration in eucaryotes Mitochondria Cell membrane Respiration in procaryotes (bacteria)
Oxidation-Reduction (Redox reactions) • Highly reduced compounds (many Hydrogens) are high in energy (glucose) • Highly oxidized compounds are low in energy (CO2)
Oxidation-Reduction (Redox reactions) (cont.) • Glucose (C6H12O6), reduced, high energy • CO2, oxidized, low energy
Glucose • Respiration (O2 or inorganic substances as electron acceptors) • Fermentation (organic substances as electron acceptors)
Glycolysis • First step in carbohydrate catabolism in both, respiration and fermentation • Does not require oxygen • 10 different reactions (enzymes)
Glycolysis Glucose -C-C-C-C-C-C - Oxidation Pyruvic acid -C-C-C- -C-C-C -
Glycolysis (cont.) • ATPs’ produced 4 • ATPs’ consumed 2 2
Pyruvic acid C-C-C (2) Oxidation Krebs cycle 6CO2 + 6H2O + 38 ATP (pro) 36 ATP (eu) Aerobic Respiration • O2required
Anaerobic respiration • Electron acceptor is an inorganic substance other than O2 (number of ATPs varies) NO3--->NO2 SO4---> H2S CO3--->CH4
Fermentation • e- acceptor is an organic substance (pyruvate) • Products • Energy • Lactic acid • Alcohol
Fermentation Glucose 2 Lactic acid 2 ATP