Chapter 5 Microbial Metabolism

Chapter 5
Microbial Metabolism

Metabolism: the sum of all chemical reactions within a living organism.
A. anabolic: (biosynthetic reactions) The combination of simpler substances into complex substances. Requires energy.
B. catabolic: (degradative reactions) Releases energy stored in organic molecules. Yields energy. Energy liberated by catabolism is stored in energy rich bonds of adenosine triphosphate. (ATP)

I Enzymes
A. Collision Theory
B. Enzymes and Chemical Reactions
C. Enzyme specificity and efficiency
D. Naming enzymes
F. Factors influencing enzymatic activity
1. temperature
a. reaction rate
b. denaturation
2. pH
a. pH optimum
3. substrate concentration
a. saturated
G. Feedback inhibition
H. Ribozymes

II Energy production (Nutrient molecules have energy stored in bonds that can be concentrated into the “high energy” [or “unstable”] bonds of ATP)
A. Oxidation – Reduction
1. dehydrogenation
2. oxidation-reduction
a. NAD
b. NADP
B. Generation of ATP
1. phosphorylation
2. oxidative phosphorylation
3. electron transport chain
4. substrate-level phosphorylation
5. photophosphorylation

III Metabolic Pathways of Energy Production
A. metabolic pathway
IV Carbohydrate Catabolism *************
A. glycolysis:
1. Pyruvic acid
2.
B. Cellular respiration
1. aerobic
2. anaerobic
C. Krebs cycle
1. decarboxylation
D. Electron transport chain
1. flavoproteins
2. cytochromes
3. ubiquinones (coenzyme Q)
E. Chemiosmotic Mechanism of ATP Generation
1. chemiosmosis
F. Summary of Aerobic Respiration: Prokaryotes generate 38 molecules of ATP aerobically for each molecule of glucose; eukaryotes produce only 36.
G. Anaerobic respiration:
H. Fermentation
1. lactic acid
2. ethanol
3. homolactic
4. heterolactic
I. Lipid catabolism
1. beta oxidation
J. Protein catabolism
1. deaminated: NH2 removed
2. decarboxylated: COOH removed

V Photosynthesis
A. photosynthesis
1. photophosphorylation
2. cyclic photophosphorylation
3. noncyclic photophosphorylation
4. Calvin-Benson cycle
B. metabolic diversity among organisms
1. phototrophs
2. chemotrophs
3. autotrophs
4. heterotrophs
5. photoautotrophs
a. green sulfur bacteria
b. purple sulfur bacteria
c. anoxygenic
d. oxygenic
6. photoheterotrophs
a. green nonsulfur bacteria
b. purple nonsulfur bacteria
7. chemoautotrophs

8. chemoheterotrophs
a. saprophytes
b. parasites
VI Metabolic pathways of energy use
A. polysaccharides
B. lipids
C. amino acids
D. amination
E. transamination
F. nucleotides
1. purine
2. pyrimidine
VII Integration of metabolism
A. Amphibolic pathways