Unit 2 - Bacterial Nutrition Flashcards
What are the 4 main macronutrients needed for bacterial nutrition?
What are some other minor micronutrients that bacteria need?
- Carbon
- Oxygen
- Nitrogen
- Hydrogen
- Sulfur, Phosphorus….Se kinda
What are the 4 avenues in which a bacteria can acquire cabon??
- Sugars - permeases break down sugars
- Amino Acids - certain bacteria will have “high-affinity uptake systems” for amino acids
-
Nucleotides - uptake or competence
- BmpA-NupABC - ABC transporter for all nucleosides
- Com protieins of Bacillus subtilis - natural competence
-
From CO2
- some organisms can convert CO2 into organic carbon
How can bacteria acquire Nitrogen?
- Atmospheric nitrogen has to be converted into a bioavailable form - like NH4 or NO2-
- there are nirtogen fixing and nitrofying bacteria that do this.
- Obtained from inorganic or organic sources
- Break down of animals, plants, other microbes
- Chemical processes that produce ammonia or nitrates
What is one mechanism in which bacteria use to acquire nitrogen?
iron-fixing bacteria
Siderophores
Magnetite deposits
Answer: Siderophores
What is a Siderophore?
- a high iron affinity molecule within bacteria
- Can be diffsed into the environment & then re-uptaked by membrane transport system.
What do most microbes use to generate energy?
Electron transport
A redox reaction usually involves reactions between [blank]?
intermediates/carriers
What are 2 classes of electron carriers?
-
Prosthetic groups
- attached to an enzyme
-
Coenzymes (diffusible)
- Nad+, NADP
- Can be recycled sometimes
What are 3 examples of compounds that store energy after it has been released from a redox reaction?
- ATP (prime energy currency)
- Phosphoenolpyruvate
- Glucose 6-phosphate
What are the 2 reaction series linked with energy conservation?
How do they differ?
- Fermentation & Respirations
- Fermentation
- substrate-level phophorylation; ATP directly synthesized from an energy-rich intermediate
- Respiration:
- Oxidative phosphorylation; ATP produced from proton motive force formed by trnasport of electrons
- Is fermentation a aerobic process?
- What macromolecule is consumed?
- How many ATP are produced per glucose?
- What are some of the byproducts?
- Anaerobic
- Glucose is consumed
- 2 ATPs/glucose
- Products = lactate or ethanol or both
Anaerobic Respiration vs Aerobic Respiration
Aerobic Respiration
- What is the terminal elecron acceptor?
- How many ATPs/glucose?
- What generates these ATP?
Anaerobic Respiration
- Use electron acceptors like??
Aerobic
- Oxygen
- 34 ATPs/glucose
- proton motive force
Anaerobic
- Fumarate, sulfate, sulfer, CO2, Fe(II) etc…
What is the TCA cycle?
- pathway through which pyruvate is completely oxidized to CO2
Which energetics process can actually generate precursors to amino acids, nucleotides, and fatty acids?
TCA Cycle
TCA Cycle by the #s
- How many CO2/glucose?
- How many NADH or FADH2/glucose?
- How many GTP/glucose?
- 6 CO2
- 8 NADH and 2 FADH2
- 2 GTP
Where is the ETC located in bacteria?
Membrane (no mitochondria in bacteria)
In bacteria, which “side” is positive/negative in order to use the proton motive force?
- Inside becomes electrically negative
- Outside becomes electrically positive
Why can’t microorganisms use CO2 for their organic carbon needs?
- Trick!
- They can. Some microorganisms can convert CO2 to organic carbon
If no Oxygen is present what are 2 mechanisms a microbe can use to utilize glucose?
- Ferment the pyruvate from glycolysis, to ethanol and/or lactic acid
- Put pyruvate through TCA cycle, ETC, and use an anaerobic electron acceptor.
Chemotrophy refers to?
Phototrophy refers to?
- uses energy from bond breakage form chemicals
- Energy from light
Lithotrophy uses what to obtain reducing equivalents?
Organotrophy uses what for reducinga gents?
- Lithotrophy - inorganic subtrate - H2, H2S, NH3
- Organotrophy - catabolism of organic compounds
- NADH from glucose breakdown
A heterotroph receives carbon from….what?
A Autotroph receives its carbon from…?
- Hetero - metabolism of organic compounds
- Auto - CO2 fixation only
What is the difference between a defined mixture and a complex mixture?
- Defined - precise mixture of purified components
- Complex - precise/loose mixture of impure products
Can all organisms that grow in an enriched medium, also grow in a general medium like an LB agar plate?
- No - an enriched medium is meant for organisms that can be “difficult to grow” in a general media.
- Ex: Chocolate agar
Another name for “difficult to grow” organisms?
Fastidious
What is the difference between selective medium and differential medium?
- Selective - only certin organisms will grow
- Differential - can differentiate organisms absed on morphological changes
What protein is critical to the elongation of a prokaryotic cell during binary fission?
MreB
What are some of the “known” characteristics of MreB that help in cell wall elongation?
- The sites at which MreB touch the cell wall are the sites in which the cell is elongating.
Do all rod bacteria have MreB?
What do MreB mutant rods become?
What does this tell you about the MreB in these mutant bacteria?
- Yes
- Rods become coccoid when MreB is mutant
- Naturally coccoid bacteria lack MreB
What are the 4 steps of peptidoglycan Synthesis?
- Clip existing peptiodglycan chains
- Autolysins - hydrolyzes B 1-4 glycosidic bonds
- Endopeptidases also help break these bonds
- Getting NAG and NAM units into periplasm
- Bactoprenol - hydrophobic lipid carrier binds to NAH and NAM and transport them across cytoplasmic membrane
- Inserting into existing peptiodglycan polymer
- transglycosylases - insert into backbone
- Carboxypeptidases - cleave terminal amino acid in peptide chain
- Crosslinking units back together
- transpeptidases - form cross links
What are the main Fts proteins involved in cell separation during binary fission?
What is the function of each?
- FtZ - “tubulin” type protein that forms a ring at the center of the cell.
- localizes divisome.
- FtsA/ZipA - anchors FtZ ring to membrane
- FtsI - Peptidoglycan synthesis component
What do the Min C & Min D proteins do during binary fission?
- inhibit FtsZ on the poles of the cell
What does MinE do during cell seperation of binary fission?
- Helps localize FtsZ to center of cell by sweeping away MinC and MinD
Cell Shape and Division in Archaea?
Do they contain FtsZ and MreB?
- Mechanism not understood
- Some archaeal genomes contain FTsZ and MreB
- Some have an “actin” homolog - crenactin or arcadins
- not found in eyrarchaeota, form helical bundles.
What are the 4 ways to measure cell population growth?
- Microscopy
-
Viable Cell Plate Count
- use 10x serial dilution.
- looking for 30-300 colonies on a plate
- Spectrophotmetry - shoot light through and measure the amount of light that gets through
-
FACS - Fluorescence Activated Cell Sorting
- very uncommon. Sorts by different things like FP and CFP, small/large, rod/cocci
