1 / 16

Bacterial metabolism

Bacterial metabolism. by E. Börje Lindström. This learning object has been funded by the European Commissions FP6 BioMinE project. Definitions. Metabolism:. - all chemical reactions occurring in a cell. With respect to function:. biosynthesis (anabolic reactions)

joel-mays
Download Presentation

Bacterial metabolism

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bacterial metabolism by E. Börje Lindström This learning object has been funded by the European Commissions FP6 BioMinE project

  2. Definitions Metabolism: - all chemical reactions occurring in a cell • With respect to function: • biosynthesis (anabolic reactions) • energy production (catabolic reactions) • exergonic reactions: - releases working energy (DG < 0) • endergonic reactions: - consumes energy (DG > 0) • co-enzyme: • a low-molecular-weight molecule, that participates in an enzymatic reaction • excepts and donates electrons and functional groups

  3. Catabolism ATP is produced by: • Photosynthesis - light energy  ATP • Chemo synthesis • chemical energy  ATP • substrate level phosphorylation • oxidative phosphorylation • red-ox reactions • electron donator; Ared  Aox • electron receiver: Box  Bred • Processes in chemo synthesis: • Respiration • Fermentation

  4. Respiration • Box = inorganic substance • Model system: - glucose • 4 processes: • Glycolysis • Oxidative decarboxylation • Krebs cycle (TCA) • Electron transport chain

  5. Glycolysis Embden-Meyerhof-Parnas pathway (EMP) • Occurs in two steps: • Activation • Oxidation (the carbon atom is oxidized) • Summary of the reaction: Glucose + 2 NAD  2 pyruvate + 2 NADH + 2 ATP

  6. Decarboxylation of pyruvate 2 pyruvate + 2 NAD+ + 2 CoASH  2 acetyl~SCoA + 2 NADH

  7. Krebs cycle (TCA) • 2 functions in the cell: • Catalyst in the energy metabolism • Start material for biosynthesis of e.g. Amino acids 2 acetyl~SCoA Krebs (TCA) 2 CO2 2 CO2 2 x 4 NADH

  8. NAD+ FADH2 Ared Bred CYT. …… Aox Box NADH FADH+ ATP ATP ATP Electron transport chain Two (2) functions: • Transfer of electrons from NADH Box • produce ATP (oxidative phosphorylation) • Mechanism: • H atoms from NADH is separated into • e- (electrons)  Box • H+ (protons)  outside of cytoplasm membrane • pH gradient is produced (proton motive force, PMF)

  9. Box examples Process Box • aerobic respiration: - O2 • anaerobic respiration: • NO3-, NO2- • SO42-, S0 • CO2

  10. NO3- SO42- CO2 O2 Box examples, cont. Lake Bred  H2O  NO2- ; NH3 ; N2 Sediment  S2- (black sediment)  CH4 (methane)

  11. Fermentation • Box is an organic substance • often an internal substance • the process is anaerobic • no functional electron transport chain • it can however exist in some micro-organisms Model system: - Glucose (Ox.)  (Red.) Glucose pyruvate End products ( naming the process)  (3 alt.) (7 alt.)

  12. Lactic acid fermentation 1) Homo-fermentative: EMP  Glucose 2 pyruvate + 2 ATP + 2 NADH Ox. Box Red. 2 Lactic acid + 2 NAD+ Application: • Yoghurt • Cheese • Butter • Sausages, etc.

  13. Lactic acid fermentation, cont. 2) Hetero-fermentative: -Phosphoketolase pathway (ox.step) NADH 2 NADH Ox.   Glucose 6-P-gluconate Pyruvate +acetyl~P + CO2 + ATP Ox. ATP Red. 2 NAD+ ethanol NAD+ Lactic acid Summary: Glucose  lactic acid + ethanol + CO2 + ATP Application: • Kefir, etc.

  14. Ethanol fermentation Organism: - Saccharomyces cerevisiae (yeast) EMP  Glucose 2 pyruvate + 2 ATP + 2 NADH Ox. CO2 2 acetaldehyde (Box) 2 NAD+ 2 ethanol Applications: • Wine • Beer • Vodka • Bread

  15. 2 NAD+ 2NADH 2NADH 2 NAD+ 2 NAD+ 2 NAD+ 2 NAD+ 2NADH 2NADH 2 NAD+ 2 NADH Mixed acid fermentation Bacteria: • E. coli; Salmonella; Shigella, etc. Three (3) processes in the cell: 1) glucose  2 pyruvate  2 lactic acid 2 ATP ethanol CO2 + H2 2) glucose  2 pyruvate  CH3-CO~SCoA + HCOOH 2 ATP acetic acid + ATP CH3-CO~SCoA + formic acid (1) 3) glucose  2 pyruvate succinate (1) 2 ATP

  16. Mixed acid fermentation, cont. Applications: • Diagnose of pathogenic bacteria (clinical bacteriology) • Analysis of water in swimming pools etc.

More Related