Bacterial metabolism
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Bacterial Metabolism. Metabolism Sum up all the chemical processes that occur within a cell 1. Anabolism: Synthesis of more complex compounds and use of energy 2. Catabolism: Break down a substrate and capture energy. Overview of cell metabolism. Bacterial Metabolism. Autotroph:

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Bacterial metabolism
Bacterial Metabolism

Metabolism

  • Sum up all the chemical processes that occur within a cell

    1. Anabolism: Synthesis of more complex compounds and use of energy

    2. Catabolism: Break down a substrate and capture energy



Bacterial metabolism1
Bacterial Metabolism

  • Autotroph:

    Photosynthetic bacterial

    Chemoautotrophic bacteria

  • Heterotroph:

    Parasite

    Saprophyte


Energy Generating Patterns

  • After Sugars are made or obtained, they are the energy source of life.

  • Breakdown of sugar(catabolism) different ways:

    • Aerobic respiration

    • Anaerobic respiration

    • Fermentation


Photosynthesis
Photosynthesis

(1) Higher plants

  • Light reaction:

    Photolysis of H2O produce ATP and NADPH

  • Two photosystem (I & II)

    Dark fixation: use the production from light reaction (ATP and NADPH) to fix CO2

    Reaction:

    6CO2 + 6H2O -----> C6H12O6 +6O2

    (Light and chloroplast)


Bacteria photosynthesis
Bacteria Photosynthesis

i. Only one photosystem can not do photolysis of H2O

ii. H2O not the source of electron donor

iii. O2 never formed as a product

iv. Bacterial chlorophyll absorb light at longer

W.L.

v. Similar CO2 fixation

vi. Only has cyclic photophosphorylation


How the bacteria synthesize nadph
How the Bacteria synthesize NADPH

  • Grow in the presence of the H2 gas

    H2 + NADP+ ------------- NADPH2

    hydrogenase

  • Reverse the electron flow in the e- transport chain

    H2S S

    S + NADP+-------- SO4-2 + NADPH2

    Succinate Fumarate

  • Simple non-cyclic photosynthetic e- flow





Anoxygenic versus oxygenic phototrophs 2
Anoxygenic versus oxygenic phototrophs(2)


Anoxygenic versus oxygenic phototrophs 1
Anoxygenic versus oxygenic phototrophs(1)


Photosynthetic bacteria
Photosynthetic bacteria

(1) Chlorobium-green sulfur bacteria

Use green pigment chlorophyll

Use H2S (hydrogen sulfide), S (sulfur), Na2S2O3 (sodium thiosulfate) and H2 as e- donors.

(2) Chromatium-purple sulfur bacteria

Use purple carotenoid pigment, same e-donors

(3) Rhodospirillum-non sulfur purple bacteria

Use H2 and other organic compounds such as isopropanol etc, as e-donors.

Reaction: CO2 + 2H2A -----> CH20 + H20 +2A

  • A is not O


Chemautotroph
Chemautotroph

  • Some bacteria use O2 in the air to oxidize inorganic compounds and produce ATP (energy). The energy is enough to convert CO2 into organic material needed for cell growth.

  • Examples:

    Thiobacillus (sulfur S)

    Nitorsomonas (ammonia)

    Nitrobacter (nitrite)

  • Various genera (hydrogen etc.)


Aerobic respiration
Aerobic respiration

  • Most efficient way to extract energy from glucose.

  • Process: Glycolysis

    Kreb Cycle

    Electron transport chain

  • Glycolysis: Several glycolytic pathways

  • The most common one:

    glucose-----> pyruvic acid + 2 NADH + 2ATP


Aerobic respiration1
Aerobic respiration

  • Euk.

    glucose -----> G-6-P----->F-6-P----->

    …... 2 pyruvate +2ATP + 2NADH

  • Prok.

    glucose-----> G-6-P------>F-6-P

  • Process take places during transport of the substrate. Phosphate is from phosphoenolpyruvate (PEP)

    .....-----> 2 pyruvate +2ATP + 2NADH


  • Kreb cycle:

    Pyruvate + 4NAD + FAD ----->

    3CO2 +4NADH + FADH

    GDP + Pi -----> GTP

    GTP + ADP -----> ATP + GDP

  • Electron trasnport Chain

    4HADH -----> 12 ATP

    FADH ------> 2 ATP Total 15 ATP

    Glycolysis -----> 8 ATP

  • Total equation:

    C6H12O6 + 6O2 ------> 6CO2 + 6H2O + 38 ATP





Anaerobic respiration
Anaerobic respiration

  • Final electron acceptor : never be O2

  • Sulfate reducer: final electron acceptor is sodium sulfate (Na2 SO4)

  • Methane reducer: final electron acceptor is CO2

  • Nitrate reducer : final electroon acceptor is sodium nitrate (NaNO3)

    O2/H2O coupling is the most oxidizing, more energy in aerobic respiration.

    Therefore, anaerobic is less energy efficient.


Fermentation
Fermentation

  • Glycosis:

    Glucose ----->2 Pyruvate + 2ATP + 2NADH

  • Fermentation pathways

    a. Homolactic acid F.

    P.A -----> Lactic Acid

    eg. Streptococci, Lactobacilli

    b.Alcoholic F.

    P.A -----> Ethyl alcohol

    eg. yeast


c. Mixed acid fermentation

P.A -----> lactic acid

acetic acid

H2 + CO2

succinic acid

ethyl alcohol

eg. E.coli and some enterbacter

d. Butylene-glycol F.

P.A -----> 2,3, butylene glycol

eg. Pseudomonas

e. Propionic acid F.

P.A -----> 2 propionic acid

eg. Propionibacterium






Energy carbon classes of organisms
Energy/carbon classes of organisms




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