MicroBiol Coredump E2

3 topics covered in exam

Microbial Nutrition and Growth

essential nutrients are needed for survival

general essential nutrients (GEN)

SPONCH = [Sulfur, Phosphorus, Oxygen, Nitrogen, Carbon, Hydrogen] are needed at an absolute minimum (at the very least, not amt)

growth factor = organic molecule the microbe cannot make itself. Might need preassembled aminic acid. Includes amino acids, vitamins, nucleotides

S by proteins; P from ATP, nucleic acids, phopolipids (easy)

N: via proteins, nucleic acids (considered difficult)

Generally parasites use organic form for S

specific essential nutrients (SEN)

individual needs of microbes. Diatons need silicon, bacteria does not need Si, but needs Fe

Difference between (GEN) and (SEN)

GEN are universal, while SEN are specific? Not All SEN's are needed at an absolute minimum like GEN.

• energy source types
  • phototroph
    • Get energy from light → photons
  • chemotroph
    • Get chemicals from inorganic chemicals
    • lithotrophs – Get E from inorganic chemicals
    • organotrophs – Get E from organic chems (C,H) at a min

• Carbon source types
  • autotroph
    • uses inorganic CO₂
    • mentions methanogens
      • 4H₂+CO₂ → CH₄+2H₂O
  • heterotroph
    • Obtain C from organic form
    • CHO's, proteins, lipids, etc
• Some combinations
  • Photoautroph – E from light, C form CO₂
    • eg. Thermus aqnaticus
  • Chemoheterotroph – energy from chem, carbon from organic source

//These are the 4 main arrangements, 16 possible combinations?

Know the various oxygen requirements/tolerances for the categories we went over in class

Oxygen is used in macromolecules and sometimes in respiration

organisms that use O₂ as their final e^- acceptors in respiration are called obligate aerobes. That acceptor needs to be there waiting at the end or you won't make ATP → dead.

Aerobic respiration

Glucose [(CH₂O)_n] + O₂ → CO₂ + H₂O + Energy (ATP)

obligate anaerobes are killed by O₂. There might be intermediate steps.. e^- + O₂ → radicals. They won't have the enzymes to break down these and they'll damage via free radicals.

facultative anaerobe → don't need O₂ , but can use it

aerotolerant anerobe → don't need O₂, aren't killed by it, don't use?

catalase : if bubbles are seen, it's not an obligate anaerobe since we can see that it can properly deal with O₂, or at least is trying to

concerning hydrogen, don't worry about with with SPONCH. Too much of it is around already.

cardinal temperatures: set of temps unique to each type/species

minimum : lowest temperature for survival, they aren't dead yet but close. Just surviving, not much growth

optimum: best temperature for growth/enzymatic reactions, lots of growth

maximum: highest temperature organisms can survive at, not much growth

psychrophiles : 0(or below)-20C, opt@15

psychotrophs

facilitative psychorophiles

mesophiles: 20-45C, opt@20-40

thermophiles: by plot 40-80C. Opt @~65C

hyperthermophiles

extremethermophiles

//do not relie on freezing to kill a microbe unless if hyperthermohile, they can exist at low temps. Boiling is preferred

//Thermus aqnaticus

acidophiles – 0-5.5 ph

alkaliphiles – 5.5 – 8.0 ph

halophiles - 9 – 30% salinity (exist in pink crystals)?

Halotolerant 5-6% salinity

osmophiles

osmotolerant

Q: If you pull out infested Jam from fridge, wha tis it?

Osmotolerant and pschrotroph (possible)

binary fission / transverse fission
• Replication/Partitioning
  • 1 mother cell --> 2 daughter cells
  • origin of replication → start copying DNA
• Septation/cytokenesis
  • forms a ring in the center of the cell, attached to cell membrane
  • add peptidoglycan
  • Z-ring contracts → splits cell apart

//cycle time = generation or doubling time

what happens during each of those two main stages to create two cells

Know the stages of the microbial growth curve and what is happening with the cells at those various stages

• Lag phase
  • adjusting to environment, gathering nutrients getting ready to divide
• Log/exponential phase
  • rapid cell division, more cells being produced than dying
  • N_f = (N_i)2ⁿ
• stationary
  • net = 0, nutrients get used, waste products get made and kill off population
• death
  • more cells dying than produced

there is a sample problem with this.

Q: to get n, n = (duration/standard doubling time)

thus, if sdt = 20, and duration = 240, n = 240 / 20, then N_f = (N_i)2ⁿ

//she used the book example*

Know the difference between symbiosis and non-symbiosis; know the various categories in those types of interactions

• symbiotic
  • @least needs the other to survive
  • Mutualism
    • both benefit
  • Commensalism
    • one benefits, the other is unaffected
  • Parasitism
    • One benefits, one is harmed
    • //anytime we get sick..
  • //Termite example:
    • They don't have the enzymes needed to digest wood cellulose, but they have the enzyme cellulase
    • protozoa have bacteria on/in it
    • bacteria live on/in protozoa, helps them produce cellulase
    • termite gets glucose
    • err.. cellulose ---(with cellulase)--> glucose
    • orgs xfered through silava
  • another ex. Us e.coli, et other one
    • e.coli will take O₂ in our intestents, and little pocktes inbetween cells won't have O₂
    • now, there's bacteriodes → obligate anaerobes that live there. If they get hit with O_2, they die

• non-symbiotic
  • Synergism
    • both benefit
  • Antagonism
    • one benefits, one is harmed
      • ex. penicillum colony vs bacteria
      • fungi produces toxin...
  • interacts /w one another, does not need other to survive
  • Some are beneficial, some are harmful

-Know the stages of biofilm formation and what is happening in those various stages

• Van Leeuwenboek via teeth scraping
• microbes grow together in close assocation
  • symbiotic
  • non-symbiotic?
• Bio-Films
  • attachment
    • Planktonic bacteria attachment
    • inducer molecules releases
      • these inducer molecules signal others to come over to initial attachment sites
      • /w enough they'll eventually reach a quorum
  • quorum
    • number of individuals needed to start forming matrix/biofilm
  • matrix development/maturation
    • cells act as a single unit, not individuals
  • matrix composition
    • polysaccharides, Proteins,Fimbriae, Pili
  • matrix function
    • Protection
      • film can block antibodies, keep antibodies from reaching cells
    • Genetic exchange
      • DNA binding proteins → help them hold onto DNA and maybe use it. One cell would spill its contents, another can pick I tup
  • matrix structure
    • differences in nutrients, temperatures, and oxygen levels
• There are a number of quorum-dependent proteins (qdp)
  • inducer molecule → chromosome → qdp
• //nitch concentration differences?
  • Top may offer most? These changes allow cells to behave differentially, than each other. They'll function as a unit and divide up tasks.
  • //@ top, lots of O₂ and it's used for respiration → ATP
  • //at bottom, cells have acccess to a lot of nutrients
  • //cells at top will produce a lot of energy that they'll share with cells at the bottom, while bottom cells share nutrients with them. Thus, a biofilm can act as a multicellular organism.

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TBC