Unit 2 - Bacterial Nutrition

Question 1

What are the 4 main macronutrients needed for bacterial nutrition?

What are some other minor micronutrients that bacteria need?

Answer 1

1. Carbon
2. Oxygen
3. Nitrogen
4. Hydrogen
5. Sulfur, Phosphorus….Se kinda

Question 2

What are the 4 avenues in which a bacteria can acquire cabon??

Answer 2

• 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

Question 3

How can bacteria acquire Nitrogen?

Answer 3

• 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

Question 4

What is one mechanism in which bacteria use to acquire nitrogen?

iron-fixing bacteria

Siderophores

Magnetite deposits

Answer 4

Answer: Siderophores

Question 5

What is a Siderophore?

Answer 5

• a high iron affinity molecule within bacteria
  
  • Can be diffsed into the environment & then re-uptaked by membrane transport system.

Question 6

What do most microbes use to generate energy?

Answer 6

Electron transport

Question 7

A redox reaction usually involves reactions between [blank]?

Answer 7

intermediates/carriers

Question 8

What are 2 classes of electron carriers?

Answer 8

• Prosthetic groups
  
  • attached to an enzyme
• Coenzymes (diffusible)
  
  • Nad+, NADP
  • Can be recycled sometimes

Question 9

What are 3 examples of compounds that store energy after it has been released from a redox reaction?

Answer 9

1. ATP (prime energy currency)
2. Phosphoenolpyruvate
3. Glucose 6-phosphate

Question 10

What are the 2 reaction series linked with energy conservation?

How do they differ?

Answer 10

1. Fermentation & Respirations
2. Fermentation
   
   1. substrate-level phophorylation; ATP directly synthesized from an energy-rich intermediate
3. Respiration:
   
   1. Oxidative phosphorylation; ATP produced from proton motive force formed by trnasport of electrons

Question 11

1. Is fermentation a aerobic process?
2. What macromolecule is consumed?
3. How many ATP are produced per glucose?
4. What are some of the byproducts?

Answer 11

1. Anaerobic
2. Glucose is consumed
3. 2 ATPs/glucose
4. Products = lactate or ethanol or both

Question 12

Anaerobic Respiration vs Aerobic Respiration

Aerobic Respiration

1. What is the terminal elecron acceptor?
2. How many ATPs/glucose?
3. What generates these ATP?

Anaerobic Respiration

1. Use electron acceptors like??

Answer 12

Aerobic

1. Oxygen
2. 34 ATPs/glucose
3. proton motive force

Anaerobic

1. Fumarate, sulfate, sulfer, CO2, Fe(II) etc…

Question 13

What is the TCA cycle?

Answer 13

• pathway through which pyruvate is completely oxidized to CO2

Question 14

Which energetics process can actually generate precursors to amino acids, nucleotides, and fatty acids?

Answer 14

TCA Cycle

Question 15

TCA Cycle by the #s

1. How many CO2/glucose?
2. How many NADH or FADH2/glucose?
3. How many GTP/glucose?

Answer 15

1. 6 CO2
2. 8 NADH and 2 FADH2
3. 2 GTP

Question 16

Where is the ETC located in bacteria?

Answer 16

Membrane (no mitochondria in bacteria)

Question 17

In bacteria, which “side” is positive/negative in order to use the proton motive force?

Answer 17

• Inside becomes electrically negative
• Outside becomes electrically positive

Question 18

Why can’t microorganisms use CO2 for their organic carbon needs?

Answer 18

• Trick!
• They can. Some microorganisms can convert CO2 to organic carbon

Question 19

If no Oxygen is present what are 2 mechanisms a microbe can use to utilize glucose?

Answer 19

1. Ferment the pyruvate from glycolysis, to ethanol and/or lactic acid
2. Put pyruvate through TCA cycle, ETC, and use an anaerobic electron acceptor.

Question 20

Chemotrophy refers to?

Phototrophy refers to?

Answer 20

1. uses energy from bond breakage form chemicals
2. Energy from light

Question 21

Lithotrophy uses what to obtain reducing equivalents?

Organotrophy uses what for reducinga gents?

Answer 21

1. Lithotrophy - inorganic subtrate - H2, H2S, NH3
2. Organotrophy - catabolism of organic compounds
   
   1. NADH from glucose breakdown

Question 22

A heterotroph receives carbon from….what?

A Autotroph receives its carbon from…?

Answer 22

1. Hetero - metabolism of organic compounds
2. Auto - CO2 fixation only

Question 23

What is the difference between a defined mixture and a complex mixture?

Answer 23

• Defined - precise mixture of purified components
• Complex - precise/loose mixture of impure products

Question 24

Can all organisms that grow in an enriched medium, also grow in a general medium like an LB agar plate?

Answer 24

• No - an enriched medium is meant for organisms that can be “difficult to grow” in a general media.
  
  • Ex: Chocolate agar

Question 25

Another name for "difficult to grow" organisms?

Answer 25

Fastidious

Question 26

What is the difference between selective medium and differential medium?

Answer 26

* Selective - only certin organisms will grow * Differential - can differentiate organisms absed on morphological changes

Question 27

What protein is critical to the elongation of a prokaryotic cell during binary fission?

Answer 27

MreB

Question 28

What are some of the "known" characteristics of MreB that help in cell wall elongation?

Answer 28

* The sites at which MreB touch the cell wall are the sites in which the cell is elongating.

Question 29

Do all rod bacteria have MreB? What do MreB mutant rods become? What does this tell you about the MreB in these mutant bacteria?

Answer 29

1. Yes 2. Rods become coccoid when MreB is mutant 3. Naturally coccoid bacteria lack MreB

Question 30

What are the 4 steps of peptidoglycan Synthesis?

Answer 30

1. Clip existing peptiodglycan chains 1. _Autolysins_ - hydrolyzes B 1-4 glycosidic bonds 2. Endopeptidases also help break these bonds 2. Getting NAG and NAM units into periplasm 1. _Bactoprenol_ - hydrophobic lipid carrier binds to NAH and NAM and transport them across cytoplasmic membrane 3. Inserting into existing peptiodglycan polymer 1. _transglycosylases_ - insert into backbone 2. _Carboxypeptidases_ - cleave terminal amino acid in peptide chain 4. Crosslinking units back together 1. _transpeptidases_ - form cross links

Question 31

What are the main Fts proteins involved in cell separation during binary fission? What is the function of each?

Answer 31

1. FtZ - "tubulin" type protein that forms a ring at the center of the cell. 1. localizes divisome. 2. FtsA/ZipA - anchors FtZ ring to membrane 3. FtsI - Peptidoglycan synthesis component

Question 32

What do the Min C & Min D proteins do during binary fission?

Answer 32

* inhibit FtsZ on the poles of the cell

Question 33

What does MinE do during cell seperation of binary fission?

Answer 33

* Helps localize FtsZ to center of cell by sweeping away MinC and MinD

Question 34

Cell Shape and Division in Archaea? Do they contain FtsZ and MreB?

Answer 34

* 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.

Question 35

What are the 4 ways to measure cell population growth?

Answer 35

1. **Microscopy** 2. **Viable Cell Plate Count** 1. use 10x serial dilution. 2. looking for 30-300 colonies on a plate 3. **Spectrophotmetry** - shoot light through and measure the amount of light that gets through 4. **FACS -** Fluorescence Activated Cell Sorting 1. very uncommon. Sorts by different things like FP and CFP, small/large, rod/cocci