4.3.18 Biochemistry II Flashcards
What are the 7 factors affecting bacterial growth
nutrients, energy source, carbon source, terminal electron acceptor, oxygen, pH, temperature
Nutrients is where we get ___ sources & various trace nutrients
C, N, P
Non-fastidious vs. fastidious
Non-fastidious - grows on simple salts
fastidious - difficult to culture based on growth conditions & nutritional needs
oxygen varies from ___ to ___
essential to toxic
Many bacteria are ___ & ___, where do they get their carbon & energy source?
Many bacteria are chemoheterotrophs or heterotrophs
Energy source = organic compounds
Carbon source = organic compounds
bacterias major goal. How do they harness energy to drive reactions?
replicate itself
Harness the energy from delta G from breakdown (catabolic) reactions to drive biosynthetic (anabolic) reactions
Describe -delta G
-delta G = exergonic reaction = energy released & is available for work
Describe catabolism. It releases energy harnessed in? What is this done through?
degeneration = breakdown of molecules
Release energy trapped in molecules
Released energy are harnessed in PMF, NAD(P)H, & ATP to do cellular work
Done through glycolysis, tricarboxylic acid cycle
Describe anabolism. Where does it get energy from? What is this done through?
biosynthesis = biosynthesis of molecules
Using energy that was harnessed from catabolism (movement of electrons down the gradient in PMF, hydrolysis of high energy phosphate bonds of ATP, oxidation of NAD(P)H)
Done through amino acid biosynthesis, fatty acid biosynthesis
Define chemical bioenergetics in the cytosol
energy captured from catabolism used to produce molecules w/ bonds w/ high free energy of hydrolysis
Define electrical bioenergetics in the cytosol
Electrons from oxidation of molecules are used to reduce molecule such as NAD(P)+ to produce NAD(P)H
High energy carries are created from
high energy bonds
Where is the ETC for bacteria located?
membrane
Explain Peter Mitchell’s chemiosmotic theory
Movement of electrons down the electrical gradient in the membrane via ETC releases energy that is used to generate electrochemical energy (PMF) across the cell membrane
H+ is electrical/chemical & pH = log 1/H+ is electrical/chemical
electrical
chemical
PMF is used for what in bacteria?
ATP synthesis
Flagella mediated motility
Solute transport
pH homeostasis
T/F: fermenting bacteria produce PMF
T
Define oxidation, reduction, electron donor, electron acceptor
Oxidation = losing electrons
Reduction = gaining electrons
Electron donor = reducing agent = molecule that’s getting oxidized
Electron acceptor = oxidizing agent = molecule that’s getting reduced
Redox reactions are always
coupled
Define reduction potential
tendency to either donate or accept electrons of a molecule
Bacteria pulls different amount of energy out of chemical compound based on
terminal electron acceptor
Fermentation occurs in the ___. Is it aerobic or anaerobic? What’s its terminal electron acceptor? How is ATP generated? What is often an intermediate in the reaction?
cytosol
anaerobic
organic molecule generated within the pathway
substrate-level phosphorylation
pyruvate
Respiration occurs in the ___. Electron movement is coupled to proton extrusion to generate ___. How is ATP generated? Is it aerobic or anaerobic? Where does the terminal electron acceptor come from?
Cell membrane
PMF
using PMF via ATP synthase
BOTH
outside the pathway
Substrate level phosphorylation occurs in the ___. It is the direct transfer of ___ from an ___ to ___. It is the formation of a ___ bond
Cytosol
Direct transfer of phosphate from an organic molecule w/ a high group transfer potential (high free energy of hydrolysis) to ADP
Formation of a phosphate bond
___ is a reducing power
H
Define cellular respiration. Energy released is coupled to ___ to generate ___
utilization of the energy released from oxidation of a molecule to generate PMF via ETC
H+ translocation to generate PMF
Describe prokaryotic respiration
Can have multiple pathways that are branched & modular
Allows organism to get different amounts of energy from each compound
E. coli lacks ___ complex & doesn’t tend to use cytochrome c during ___
cytochrome bc1
aerobic respiration
Some dehydrogenases & terminal oxidases are ___ that use energy from redox reaction to translocate protons
proton pumps
Define proton pumps
Moves positively charged ions across the membrane
Moves H+ out of cell
Substrate level phosphorylation produces ___ ATP. Oxidative phosphorylation produces ___ ATP. Producing a total of
4
34
38
What are the 2 fermenting conditions pathways?
Pyruvate-ferredoxin oxidoreductase
Pyruvate-formate lyase
What is the respiring conditions pathway?
pyruvate dehydrogenase
TCA cycle steps
citrate –> isocitrate –> alpha-ketoglutarate –> succinyl-CoA –> succinate –> fumarate –> malate –> oxaloacetate
Glyoxylate pathway is not present in
mammals
Glyoxylate pathway used for metabolism of
FA & acetate
Entner-Doudoroff Pathway is only found in
prokaryotes
Why is the utilization of O2 a paradox?
b/c it’s an essential element of macromolecules & for metabolism of many bacteria, but also the precursor of some of the most dangerous agents for cellular material
Define aerobes, anaerobes, facultative anaerobes, microaerophiles, & capnophiles
- Aerobes: REQUIRE O2
- Anaerobes: ABSENCE of O2
- Facultative anaerobes: can grow in the presence or absence of O2
- Aerotolerant anaerobes: don’t use O2, but grow in the presence of O2
- Microaerophiles: only grown in low O2
- Capnophiles: can grow in high CO2
define reactive oxygen species
oxygen w/ unpaired electrons
___ removes O2 radicals. ___ removes H2O2
superoxide dismutase
catalase
H2O2 can directly inactivate enzymes & also generate ___ by interacting w/ O2 radicals
OH radicals
___ radical is the most reactive ROS & can interact w/ nearly all biomolecules
OH
Define Fenton reaction
Fe2+ mediated generation of hydroxyl radical
Presence or absence of SOD & catalases: strict anaerobes, aerotolerant anaerobes, aerobes
- Strict anaerobes: no SOD or catalases
- Aerotolerant anaerobes: SOD & a peroxidase, no catalase
- Aerobes: both SOD & catalase
What is Anaerobic sulfate reducer Desulfovibrio vulgaris & C. acetobutylicum
superoxide reductase system that allows elimination of O2 radicals w/o the generation of O2
- Don’t require O2
Describe lactic acid bacteria
NADH oxidase = unique flavoprotein that catalyzes direct 4 electrons reduction of O2 to 2 H2O
