Summary Physiology of Microorganisms (NWI-BB024B)

Physiology of microorganisms summary

Gram negative = inner + outer membrane
Gram positive = inner membrane + peptidoglycan wall

L1 introduction
Main needs for living:
- Metabolic plan
o Genome
o Regulatory systems
- Nutrients
o Macronutrients: C, H, N, O, P, S
o Micronutrients
- Enzymes

Active transport = accumulation against concentration gradient, energy driven
- Simple transport
- Group translocation
- ABC system

Simple transport:
- Symporter = protons + compound/solute are co-transported in same direction
- Antiporter = protons + compound/solute are transported in opposite direction
Driven by proton motor force (= pmf)

Group translocation:
Compound gets chemically modified during transport, mostly used for sugars
PEP = phosphorylated pyruvate: PE-P
Driven by energy rich compound

ABC transporter = ATP-binding cassette
3 parts:
- Periplasmic binding protein
- Transmembrane transporter
- ATP-hydrolysing protein
High substrate affinity -> used often
Driven by energy from ATP

Metabolism = sum of all chemical reactions
- Anabolism = required energy, makes macromolecules
o Similar in all microorganisms
- Catabolism = creates energy, breaks down molecules
o Very different per microorganism

, Metabolic classes:
Carbon source:
- Heterotrophs = get carbon from organic source
- Autotrophs = get carbon from CO2 = primary producers
Energy source:
- Chemoorganotrophs = get energy from organic sources
- Chemolithotrophs = get energy from oxidation of inorganic compounds
- Phototrophs = get energy from light conversion
o Photoautotroph = energy from light, CO2 for carbon
o Photoheterotroph = energy from light, organic source for carbon

Energy = ability to do work [kJ]
Free energy = G = energy available to do work
ΔG = G[C+D] - G[A+B] for A+B -> C+D
-> doesn’t say anything about the reaction rate
Reactions use catalysts (= enzymes) -> lower activation energy -> increase reaction rate
Co-factor = small non-protein group on enzyme
- Prosthetic group = binds covalently to enzyme
- Coenzyme = loosely bound to enzyme, carry products btwn enzymes

Redox
- Oxidation = removal of electrons
- Reduction = addition of electrons
Reduction potential = E [V]
E > 0 more reduction = acceptor
E < 0 more oxidation = donor
Further from 0 -> stronger
Bigger difference in E btwn donor and acceptor -> more free energy released = lower -ΔG

Electron carriers = shuttle electrons btwn different substrates: donor -> carrier -> acceptor
-> increase the diversity in redox reactions
Catabolism: NAD+/NADH -> carries 2 electrons
Anabolism: NADP+/NADPH -> carries 1 electron

ATP = energy currency
ATP -> ADP + P = hydrolysis = releases free energy