Microbial Metabolism

Microbial Metabolism Chapter Metabolism - all of the chemical reactions within a living organism Catabolism ( Catabolic ) • breakdown of complex organic molecules into simpler compounds • releases ENERGY Anabolism ( Anabolic ) • the building of complex organic molecules from simpler ones • requires ENERGY Enzymes - catalysts that speed up and direct chemical reactions A Enzymes are substrate specific • • • • • Lipases Sucrases Ureases Proteases DNases Lipids Sucrose Urea Proteins DNA Enzyme Specificity can be explained by the Lock and Key Theory E + S -> ES > E + P Naming of Enzymes - most are named by adding “ase” to the substrate Sucrose Lipids DNA Proteins removes a Hydrogen removes a phosphate Sucrase Lipase DNase Protease Dehydrogenase phosphotase Naming of Enzymes Grouped based on type of reaction they catalyze Oxidoreductases oxidation & reduction Hydrolases hydrolysis Ligases synthesis Enzyme Components Parts Apoenzyme - protein portion Coenzyme (cofactor) - non-protein Holoenzyme - whole enzyme Coenzymes Many are derived from vitamins Niacin • NAD (Nicotinamide adenine dinucleotide) Riboflavin • FAD (Flavin adenine dinucleotide) Pantothenic Acid • CoEnzyme A Factors that Influence Enzymatic Activity Denaturation of an Active Protein Anaerobic Respiration Electrons released by oxidation are passed down an E.T.S., but oxygen is not the final electron acceptor Nitrate (NO3-) > Nitrite (NO2-) Sulfate (SO24-) > Hydrogen Sulfide (H2S) Carbonate (CO24-) -> Methane (CH4) Fermentation Anaerobic process that does not use the E.T.S Usually involves the incomplete oxidation of a carbohydrate which then becomes the final electron acceptor Glycolysis - plus an additional step Fermentation may result in numerous end products Type of organism Original substrate Enzymes that are present and active Lactic Acid Fermenation Only ATP End Product - Lactic Acid Food Spoilage Food Production • Yogurt - Milk • Pickles - Cucumbers • Sauerkraut - Cabbage Genera: • Streptococcus • Lactobacillus Alcohol Fermentation Only ATP End products: • alcohol • CO2 Alcoholic Beverages Bread dough to rise Saccharomyces cerevisiae (Yeast) Mixed - Acid Fermentation Only ATP End products - “FALSE” Escherichia coli and other enterics Propionic Acid Fermentation Only ATP End Products: • Propionic acid • CO2 Propionibacterium sp Fermentation End Products Lipid Catabolism Protein Catabolism Photosynthesis - conversion of light energy from the sun into chemical energy Chemical energy is used to reduce CO2 to sugar (CH2O) Carbon Fixation - recycling of carbon in the environment (Life as we known is dependant on this) Photosynthesis • Green Plants • Algae Chemical Equation CO2 + H2O + sunlight -> C6H12O6 + O2 Parts: • Light Reaction • Dark Reaction Light Reaction Non-Cyclic Photophosphorylation • O2 • ATP • NADPH2 Light Reaction (simplified) Dark Reaction