CHAPTER 5: Microbial MetabolismWhy is the Study of Metabolism Important?- According to Wikipedia, “Microbial metabolism is the means by which a microbe obtains the energy and nutrients (e.g. carbon) it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe’s ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles.”- Our definition: Collection of controlled biochemical reactions that take place within cells of an organism- As a part of the disease process, pathogens acquire energy and nutrients from a host (and to the detriment of the host)- Pathogen: microorganism that causes diseaseo Main function is to replicate- Microbes are being used to clean up the oil spill in the Gulf of Mexicoo The microbes use petroleum as nutrient- Explains how microbial fermentation results in beer, wine, and breado Use nutrient as alcohol or yeasto Produces the unique flavorsMetabolism- Collection of controlled biochemical reactions that take place within the cells of an organism o Bacteria  Take place in cytoplasm Provide energy for the cell Enables the cell to duplicate itself- Contains catabolism and anabolism – cant have one without the othero Catabolism: breaks the cell into smaller pieces and provides the cell with three different things ATP Reducing power  Precursor metaboliteso Anabolism: taking small molecules and using them as starter molecules to form a larger molecule  Requires ATP Requires reducing power Requires precursor metaboliteso Everything formed in catabolism is then used in anabolismMetabolic Processes Guided by Eight Elementary Statements- Every cell acquires nutrients - Metabolism requires energy from light or from catabolism of nutrientso Depends on type of cello Derived by the breakdown of nutrients- Energy is stored in adenosine triphosphate (ATP)- Cells catabolize nutrients to form precursor metaboliteso Catabolize: breaking down which from precursor metabolites- Precursor metabolites, energy, and enzymes are used in anabolic reactions to construct larger building blocks- Enzymes plus energy anabolically link building blocks together in polymerization reactionso Anabolic: using small pieces and energy and enzymes to make something largero Making a protein from amino acids o Takes energy to link amino acids together Polymerization reaction - Cells grow by assembling macromolecules into cellular structures- Cells reproduce once they have doubled in sizeOxidation and Reduction Reactions- Transfer of electrons (which carry energy) from a molecule that donates an electron to a molecule that accepts an electron- Reactions always occur simultaneously (oxidation AND reduction)- Molecule that donates: oxidized- Molecule that accepts: reduced - In biological systems usually an electron + proton is being transferred- Cells use electron carrier molecules to carry electrons (often in H atoms)- When electrons move from donor to acceptor, free energy is released (reducing power)o When electrons move from NADH to O2 during aerobic respiration, free energy is used to synthesize ATP- Three important electron carrierso Carry electrons from one place to another o Left hand side: oxidizedo Right hand side: reduced Stores potential energy- Utilized to synthesize ATPo NAD + + 2H+ + 2e-  NADH + H+o NADP + + 2H+ + 2e-  NADPH + H+o FAD + 2H+ + 2e-  FADH2ATP Production and Energy Storage- Organisms release energy from nutrients; can be concentrated and stored in high-energy phosphate bonds of ATP (squiggly lines)- Phosphorylation: inorganic phosphate is added to substrate (ADP to create ATP); stores high energy - Cells phosphorylate ADP to ATP in three wayso Substrate-level phosphorylation: transfer of phosphate from another phosphorylated organic compoundo Oxidative phosphorylation: energy from redox reactions of respirationused to attach inorganic phosphate to ATPo Photophosphorylation: light energy used to phosphorylate ADP (not really talked about)- Anabolic pathways use some energy of ATP by breaking a phosphate bond (both squiggly line bonds can be broken)- Anabolism requires ATPRequires energy – ATP is used – bonds between phosphate groups are broken – end up with ADPEnergy is derived from this processThe Roles of Enzymes in Metabolism- Catalysts: chemicals that increase the likelihood of a reaction but are not permanently changed in the process (organic catalysts = enzymes); and often increase the rate of a chemical reaction- Naming and classifying enzymeso Most end with suffix –aseo Usually incorporate the name of the enzyme’s substrate o Lipase: enzyme that breaks down lipids - Over 1,000 enzymes exist in a single cell and each operates with extraordinary specificity and speedo Very specific in terms of the substrate they act upon- Most enzymes are proteins- Enzymes lower activation energy (energy needed to trigger a chemical reaction)Carbohydrate Catabolism- Many organisms oxidize carbohydrates as the primary energy source for anabolic reactions- Glucose is the most common carbohydrate used- Glucose is catabolized by o Cellular respiration (aerobic or anaerobic) – results in complete breakdown of glucose to carbon dioxide and water; dollar bill breaking into pennieso Fermentation – results in organic waste products; still oxidized but not completely broken down; dollar bill breaking into 4 quarters- Both cellular respiration and fermentation begin with glycolysis and results in the production of two molecules of pyruvic acido Respiration continues via the Krebs cycle and electron transport chaino Fermentation involved the conversion of pyruvic acid into other organic compoundsCarbohydrate Catabolism- Breakdown of sugars so the cell can deriveo ATPo Precursor metaboliteso Reducing power- Oxidize carbohydrates: breaking them down- Bacteria undergo metabolism because it’s trying to replicate itself- In order to reproduce they have to duplicate EVERYTHING which takes a LOT of energyo Two ways Aerobic respiration: oxygen used and is the final electron acceptor Anaerobic respiration: oxygen not used; oxygen not final electron acceptor- Glucose catabolism is like taking a dollar bill and breaking it down as far as it will go (100