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Microbial Metabolism (catabolism (Aerobic respiration (proton motive force…

- - - - energy is released and used to transport protons (H+) from the cytoplasm to the outside of the membrane, As electrons move down the ETC
      - an electrochemical gradient across the membrane that contains energy used to do work for the bacterial cell
    - - Allowing protons to come back to the inside of the membrane through ATP Synthase enzyme releases energy that is used to make ATP
    - - superoxide dismutase
      - catalase
  - - - allows colonization of anaerobic environments
      - enables adaptation to variations in oxygen availability
      - provides a means for growth when oxygen levels are too low for aerobic respiration
    - - Solvents
        
        acetone, butanol
      - Organic acids
        
        lactic acid, acetic acid
      - Alcoholic beverages
        
        ethanol and CO2
      - Vitamins, antibiotics, and hormones
  - - - Glycolysis is a common pathway used in aerobic respiration and fermentation
      - begins with glycolysis; which is the breakdown of glucose into pyruvate
      - Glucose -----> 2 Pyruvate + 2 ATP + 2 NADH
      - Most bacteria use the glycolysis pathway for breaking down glucose and making ATP (eukaryotes do too!)
    - - Acetyl-CoA enters the Krebs cycle
      - The Krebs cycle is a series of enzymatic reactions that occurs in all aerobic organisms
      - Pyruvic acid is converted to Acetyl-CoA and CO2
      - takes place in the cytoplasm of bacteria and in the mitochondrial matrix of eukaryotes
      - After glycolysis, pyruvic acid is still energy-rich
      - cycle serves to transfer the energy stored in acetyl CoA to NAD+ and FAD by reducing them (transferring hydrogen ions to them)
      - 2 APT
    - - Consists of redox carriers that receive electrons from NADH and FADH2 generated by glycolysis and the Krebs cycle
      - Released energy from electron carriers in the electron transport chain is channeled through ATP synthase
      - the final step in both aerobic and anaerobic respirations
      - the coupling of ATP synthesis to electron transport is called Oxidative phosphorylation
      - each NADH that enters the electron transport chain can give rise to 3 ATPs
      - each FADH that enters the electron transport chain can give rise to 2 ATPs
      - Location
        
        embedded in the cell membrane in prokaryotes
        
        on the inner mitochondrial membrane in eukaryotes
- - - - Holoenzyme
        
        catalase
        
        an enzyme that breaks down hydrogen peroxide and requires iron as a metallic cofactor
        
        Nicotinamide adenine dinucleotide (NAD)
        
        In cellular respiration (the process of producing energy in the cells), NAD combines with two hydrogen atoms
        
        is a combination of a protein called the Apoenzyme plus required cofactors (vitamins, metals) called coenzyme that help mediate the reaction
        
        Metallic cofactors
        
        Include Fe, Cu, Mg, Mn, Zn, Co, Se
        
        Metals activate enzymes, help bring the active site and substrate close together,
        
        participate directly in chemical reactions with the enzyme-substrate complex
        
        Coenzymes
        
        Removes a chemical group from one substrate molecule and adds it to another substrate
        
        Bind to the active site of the enzyme
        
        Organic compounds that work in conjunction with an apoenzyme to perform a necessary alteration of a substrate
        
        Vitamins: one of the most important components of coenzymes
        
        levels of molecular complexity
        
        primary
        
        secondary
        
        tertiary
        
        quaternary
  - - - extracellular enzymes secreted by a cell and functions outside of that cell
      - Amylase
        
        an exoenzyme that hydrolyzes starch into mono- and dissacharide subunits
      - secreted by bacteria into the environment in order to break down larger nutrient molecules so they may enter the bacterium
      - Lipase
        
        an exoenzyme that hydrolyzes lipids into fatty acids and glycerol
      - In disease
        
        Pseudomonas aeruginosa (many diseases)
        
        Produces Elastase and Collagenase - digest elastin and collagen
        
        Clostridium perfringens (gas gangrene)
        
        Lecithinase C - destroys tissue in wounds
        
        Streptococcus pyogenes (Strept Throat)
        
        Produces Streptokinase - digests clots
    - - intracellular enzymes that function within the cell in which they are produced.
      - Catalase
        
        an endoenzyme that breaks down superoxide molecules inside the cell
  - - - always present in relatively constant amounts regardless of the amount of substrate
      - Inhibition or direct control
        
        binding of a molecule prevents the enzyme from working
        
        Types
        
        Competitive inhibition
        
        Blockade of the action of an enzyme on its substrate by replacement of the substrate with a similar but inactive compound that can bind to the active site of the enzyme but produces no reaction
        
        Noncompetitive inhibition
        
        The inhibitor binds to an enzyme somewhere other than the active site and changes the enzyme's structure preventing normal function.
        
        Feedback inhibition
        
        the end product of an enzymatic reaction interferes with the function of the enzyme that produced it once a certain concentration is reached
      - Genetic control
        
        more long term effect
      - Repression
        
        Excess of end product binds to the genetic component and turns if 'OFF‘
      - Induction
        
        Induced by presence of substrate (i.e LACTOSE) that binds to the genetic component and turns it 'ON‘ - make enzymes necessary for action
    - - production is turned on (induced) or turned off (repressed) in responses to changes in concentration of the substrate
  - - - Maltase
        
        digests maltose
      - Proteinase, protease, peptidase
        
        hydrolyzes the peptide bonds of a protein
      - Amylase
        
        acts on starch
      - Lipase
        
        digests fats
      - Carbohydrase
        
        digests a carbohydrate substrate
      - Deoxyribonuclease (DNase):
        
        digests DNA
      - Synthetase or polymerase
        
        bonds many small molecules together
    - - Transferases
        
        transfer functional group from one substrate to another
      - Hydrolases
        
        cleaves bonds on molecules with the addition of water
      - Dehydrogenase
        
        hydrogen transfer
      - Isomerases
        
        change a substrate into its isomeric forms
      - Oxidoreductase
        
        electron transfer
      - Ligases
        
        catalyze bond formation with the addition of ATP and removal of water
- - - - : loss of electrons
      - when a compound loses electrons, it is oxidized
      - By bonding to a more electronegative atom
    - - gain of electrons
      - when a compound gains electrons, it is reduced
      - By bonding to a less electronegative atom
  - - - hydrocarbons, methane, fats, carbohydrates, alcohols
      - carry a great deal of potential chemical energy stored in their bonds.
    - - ketones, aldehydes, carboxylic acids, carbon dioxide
      - carry very little potential chemical energy in their bonds
  - - - H removed from NADH goes to electron transport chain in the membrane
    - - H removed from NADH is added to pyruvate to make alcohol or acid
  - - - 5-carbon sugar (ribose)
      - chain of three phosphate groups groups bonded to ribose
      - nitrogenous base (adenine)
    - - Substrate-level Phosphorylation
        
        ATP is formed by a transfer of a phosphate group from a phosphorylated compound (substrate) directly to ADP
      - Oxidative Phosphorylation
        
        ATP is made in a series of redox reactions occurring during the final phase of the respiratory pathway