Bacterial Metabolism - PowerPoint PPT Presentation

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Bacterial Metabolism

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Bacterial Metabolism Introduction Metabolism ... ATP generated via chemiosmosis ( proton pump ) and ATP synthase Photo - light energy from photosynthesis, ... – PowerPoint PPT presentation

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Title: Bacterial Metabolism


1
Bacterial Metabolism
  • Introduction
  • Enzymes
  • Energy Production
  • Bacterial Catabolism

2
Bacterial Metabolism
  • Introduction
  • Metabolism - sum of all chemical reactions in
    cell
  • Anabolism - reactions that synthesize or build
    up e.g. protein synthesis
  • Catabolism - reactions that digest or break
    down e.g. starch to glucose

3
Bacterial Metabolism
  • Enzyme Introduction
  • Enzyme Components
  • Enzyme Mechanism
  • Factors Influencing Enzymes

4
Bacterial Metabolism
  • Enzyme Introduction
  • Enzymes are biological catalysts
  • Catalysts are agents which speed up a reaction
  • Enzymes are very specific
  • Enzymes are typically proteins
  • Catalysts work by lowering the activation energy
    of a reaction

5
Bacterial Metabolism
  • Enzymes work to lower activation energy

6
Bacterial Metabolism
  • Enzyme Components
  • Cofactor - nonprotein component that is part of
    enzyme, e.g. Fe, NAD, biotin
  • Apoenzyme - protein portion of enzyme
  • Holoenzyme - Cofactor plus apoenzyme

7
Bacterial Metabolism
  • How enzymes speed up reactions
  • Proximity
  • Orientation
  • Induced fit
  • Reactive groups
  • Cofactors

8
Bacterial Metabolism
  • Enzyme Mechanism
  • Substrate binds to active site lock key
    specificity induced fit
  • Formation of enzyme-substrate complex
  • Catalytic activity localized acid or base or
    induced fit

9
Bacterial Metabolism
10
Bacterial Metabolism
  • Factors Influencing Enzymes
  • Temperature
  • pH
  • Salt concentration
  • Inhibitors
  • Competitive (active site)
  • Non - Competitive (allosteric)
  • Feedback Inhibition

11
Bacterial Metabolism
  • Energy Production
  • Oxidation / Reduction reactions
  • Role of ATP
  • Phosphorylation
  • Substrate
  • Oxidative
  • Photo-

12
Bacterial Metabolism
  • Oxidation / Reduction
  • Oxidation - loss of electrons
  • Reduction - gain of electrons
  • Redox reactions always coupled
  • Oxidation of reduced carbon tends to be
    energetically favorable

13
Bacterial Metabolism
  • Carbon Oxidation/Reduction
  • Carbon Dioxide CO2 (4)
  • Acid (Formic Acid HCO2) (2)
  • Aldehyde (Formaldehyde - H2CO) ( 0 )
  • Alcohol (Methanol - H3COH) (-2)
  • Methane CH4 (-4)

14
Bacterial Metabolism
  • Oxidation States
  • Alcohols
  • Fats
  • Organic Acids (acetic acid)
  • Glucose

15
Bacterial Metabolism
  • Role of ATP
  • ATP ? ADP Pi
  • Energy intermediate or currency
  • Hydrolysis of ATP coupled to energetically
    unfavorable reactions

16
Bacterial Metabolism
17
Bacterial Metabolism
  • Glucose Pi ? Glucose-6-PO4 H2O
  • ?G 13.8 kJ/mol, Keq 5 x 10-3
  • ATP H20 ? ADP Pi
  • ?G -30.5 kJ/mol, Keq 4 x 105
  • Glucose ATP ? Glucose-6-PO4 ADP
  • ?G (-30.5 kJ/mol) (13.8 kJ/mol)
  • -16.7 kJ/mol

18
Bacterial Metabolism
  • Phosphorylation
  • Substrate - direct transfer of phosphate from an
    organic molecule to ADP
  • Oxidative - ATP generated via chemiosmosis
    (proton pump) and ATP synthase
  • Photo - light energy from photosynthesis, a
    modification of chemiosmosis

19
Bacterial Metabolism
  • Bacterial Catabolism
  • Carbohydrate catabolism has two functions
  • energy production and/or storage
  • generation of chemical intermediates
  • Cellular respiration and fermentation
  • Includes three processes
  • Glycolysis
  • Krebs or Tricarboxylic Acid (TCA) cycle
  • Electron transport /oxidative phosphorylation
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