Mikro forelæsninger Flashcards
What are microorganisms?
organisms that you can’t see with the unaided eye (< 0.1 mm) mainly single cell organisms (no differentatiion of cells)
• viruses are not microorganisms
yeast, algae and fungi are miros, but are eukarytes cells.
Hvilket gen er fyloginien baseret på hos prokaryote og hvilket er hos eukayoter?
16S rRNA prokaryote
18S rRna eukayoter
How differs prokaryotes and eukaryotes whit there nucleus whit cell membrane?
Eukaryotes have, Pro dos not.
How many chromosomes does prokaryotes and eukaryotes have?
prokaryotes 1 and eukaryotes 2 or more
Does prokaryotes and eukaryotes have mitosis?
Prokaryotes don’t and eukaryotes does.
Does prokaryotes and eukaryotes have secual reproduction:
prokaryotes Rare: only part of the genome involed, and eukaryotes gommen ; all chromosomes involved .
Does prokaryotes and eukaryotes have meiosis:
Prokaryotes no and eukaryotes yes
What is the advantage of being small?
Microbes process their nutrients 10 to 1000 times faster per gram than mammalian cells. High surface to volume ratio allows quick chemical exchange.
Hvad er nitrification?
NH4+ (ammonium) –> NO3 - nitrat
Hvad er denitrifikation?
NO3- (nitrat) –> N2 (kvælstof)
Hvad er N2 fiksation?
N2 + 8H+ –> NH3 (ammoniak) + H2
Hvilket bakterier laver N2 fikation aerobt?
Cyanobakterier og azotobacter
Hvilke bakterier laver N2 fikation anaerobt?
Clostridium
Hvad er Ammonifikation?
Org-N –> NH4 (ammonium)
Hvad er anamox?
NO2- + NH3 –> 2N
Hvilke bakterier laver anamox?
Brocodia
What are sterilization and withs methods do you know?
killing of all living cells and all spores
• not all methods are 100% effective -> reduction of germs (backteriea)
depending on material that needs to be sterilized different methods are used: o heat sterilization o Pasteurization o irradiation sterilization o sterile filtration o chemical sterilization
which heat sterilizations do you now?
Cooking
(100 °C for 15 min)
kills living cells but not all spores
Moist heat and pressure
(autoclave, 121 °C, 15 psi for 15 min) kills living cells and spores
Dry heat
(160-180 °C for 2-4 hours) kills living cells and spore
What are pasteurization? And how many microbial cells does it kill?
reduces microbial cells by 79-99%
- historical method: 63-66 °C for 30 min –
- modern method: 72 °C for 15 sek
What is Irradiation?
high energy radiation destroys cell components, especially DNA -> spores are quite tolerant to radiation
– UV radiation (approx. 260 nm)
– ionizing radiation (Gamma- and X-rays, < 10 nm)
how big is a sterile filter and why?
Bacterial and archaeal cells normally have a size of 0.5-1 μm
Membrane and nucleopore filters have pore sizes of 0.2 μm and stop nearly 100% of all cells
What is chemical sterilization?
many chemicals can kill prokaryotic microorganisms
organic compounds: e.g. ethanol, phenol, formaldehyde
halogens: e.g. iodine solution, chlorine bleach
heavy metals: e.g. mercuric chloride, silver nitrate
others: e.g. hydrogen peroxide, ozone
how many % of cell cell wight is water?
75 %
What is the cytoplasmic mebranes main function?
Permeability barrier
Protein anchor (anker)
Energy conservation
What is the different in the membrane lipids between bacteria, eukaryotes and archaea?
Archer have Ether linkage, bacteria and eukaryotes have ester linkage.
What is periplasm?
Protected environment between the membranes. Nedbrydende enzyme findes her for at nedbryder molekyler der bliver transporteret ind i cellen.
Where do we find prorins?
In outer membrane transporting hydrophilic compounds (sugars, amino acids, ions)
How big can a molecyle be so they still can pass porin?
700 daltons.
What are capsules, and what do they do?
slime or capsule covering the cells to protect them.
They consist of high-molecular weight polysaccharides
How does the transcription and translation work in bacteria?
In contrast to eukaryotes transcription and translation are coupled.
What is fimbriae and phili used to?
To attach to surfaces and to form biofilms
Pili are used to attach transfer proteins and DNA and motility. All fram negative bacteria and many gram positive have it.
What does catabolism means?
Breakdown of complex molecules into smaller ones.
What does anabolism means:
reactions that build cells.
Name some bacteria who is chemoorganoheterotrophs
most bacteria, e.g. Escherichia coli, Bacillus subtilis, etc.
Which reaktions are chemolithoautotrophs
nitrifiers (NH4++O2), sulfur‐oxidizers, iron‐oxidizers, Knaldgas‐bacteria (H2+O2)
Which bacteria is chemolithoheterotrophs
some species of Thiobacilus, Beggiatoa, Nitrobacter spp., Wolinella (H2)
which bacteria is photolithoautotrophs
Cyanobacteria (H2O), Chlorobiaceae, Chromatiaceae (H2S), Chloroflexus (H2)
Which bacteria is photoorganoheterotrophs (some mixotrophic)
Rhodobacter, Rhodopseudomonas, Rhodospirillum, Rhodomicrobium, Heliobacterium, Chloroflexus
What is the netto energy output of glycolysis?
2 ATP
What is substrate-level phosphorylation?
transfer of a phosphoryl group from an organic substrate to ADP to generate ATP
what is the netto energy output of pentose phosphate pathway?
1 ARP, 2 NADPH
What is the netto energy output of entner-douoroff (ED)
1 ATP, 1 NADH AND 1 NADPH
What is entner-douoroff used to?
bruges til sugar-acid - altså glukose der er oxideret mere
end glukose-6-p
what is pentose phosphate pathway used to?
many precursors for biosynthesis of cell components (eg. pentose backbones of nucleic acids)
what is the netto energy output for TCA cycle?
2 ATP, 6 NADP + 2 FADH2
What are the netto energy output for ome molekyle of glukose?
38 ATP
Hvad er række følgen på reduktions potentialet hos, , CO2. NO3, O2, SO42 MN2+, FE,
O2, NO3, MN2+, FE, SO42 CO2.
Hvad er forskellen på type 1 og type 2 reaktions centrere?
Type I
• ferredoxin reductases
• electron acceptor is ferredoxin (iron– sulfur protein)
• ferredoxin is very electronegative (-400 mV)
• very potent reducing agent
• most of the energy from the photon is conserved
Type II
• quinone reductases
• reduces quinones to quinols
• quinols are weak reducing agent (0 to -100 mV)
• more energy dissipated in reaction center
• less efficient than type I
What is rubisco?
Rubisco consists of 8 small (S) and 8 large (L) subunits.
Catalyzes the condensation of CO2 to ribulose 1,5-bisphosphate, and the splitting of the unstable 6C intermediate into two 3C PGA molecules
Hvad kendetegner chemolithotrofe organismer?
inorganic electron donors (NH4+, NO2-, H2S)
o oxidized (usually by O2)energy
o oxidized to produce NADPH for CO2 fixation
low efficiency
low biomass but high activities
unique ecological niche – do not compete for organics
NADPH needed to reduce CO2 generated by ”reverse electron transport” at the expense of the proton potential
what does colony morphology describes?
formation of colonies
• shape of colonies
• pigmentation of colonies
• exopolymer production
What does cell morphology describes?
Shape
Size
Gram ration
Presence of flagella and their arrangement
What does motility describes?
motile by flagella
motile by gliding
buoyancy by gas vesicles
nonmotile
hvad har man I mente når man clacificere efter næringsstoffer og fysiologi?
energy conservation: phototroph, chemoorganotroph, chemolithotroph
• aerob, anaerobe
• temperature optimum
• pH optimum
• salt requirements/tolerances
• ability to use carbon, nitrogen and sulfur sources
• growth factor requirements
Hvilke andre factore kan spille ind i taxonomy os bakterier?
pigments spore formation cell inclusions surface layers pathogenicity antibiotic sensitivity
Hvordan bestemmer man ny prokaryotiske arter?
isolate new organism
• characterize it: physiological test, genome
• deposit it as type strain at a culture collection
• publish in International Journal of Systematic and Evolutionary Microbiology (IJSEM) with a proposed
name with publication name is official
• later species will be included in overview literature like Bergey’s Manual of Systematic Bacteriology
Hvorfor burger man 16rRNA til at bestemme bacterier?
General considerations
• universal – essential in all cells
• similar function – directly comparable
• 1500 bp is long enough to see useful differences
• interacts with other gene products in complex assembly critical for survival – decreases likelihood of horizontal gene transfer
Practical advantages
• conserved regions alternate with more variable regions (because all bases are functional – compare protein)
• allows reliable alignment over broad taxonomic range
• conserved regions allow for use of “universal primers” for PCR
• many sequences available for comparison in online databases
What is the definition for a prokaryotic species?
group of similar related strains that differ more from other strains than they do from each other
96-98% identity in the 16S rRNA gene
>70% genome hybridization
What is the definition for a eukaryotic species
Organisms that can interbreed and produce fertile offsprings.”
How many estimated prokaryotic species is there?
> 10 million