micro exam 2 lecture

psychrophile

cis unsaturated fatty acid - keeps membrane squishy and filled up with anti frezze solutes so ice crystals dont stab and burst it

cold - bendy

thermophiles

saturated fatty acid, chaperon proteins, and special proteins to stop dna from falling apart
hot - solid

reactive oxygen species (ROS)

microbes that live with oxygen must have antioxidant enzymes to clean up ROS

biofilms

bacteria attached to surface and builds sticky slim made of extracellular polymeric substances

helicase

unzips double standed dna

rna primase

lays down a short RNA building block

dna polymerase

builds dna 5’→3’ with matching letters

dna ligase

builds okazaki fragments on lagging strand

topoisomerase

untangles knots/supercoils after added fragments

PCR steps

denaturation 95C - breaks hydrogen bonds seperating dna

annealing 60c- cools down dna so dna primers stick to targeted gene

extension 72 c - heat stable taq polymerase builds the new dna strands

central dogma and fast microbs

dna→rna(transcription)→protein(translation)

in bacteria riboseome jumps on mrna while being made a coupled transcription trnaslation allowing fast growth

virus strcuture

-capsid (protein coat) protecting nucleic acid genome

-some have envelope (lipid membrance stolen from the host) embedded viral spike proteins used to grab host cells

rna dependent rna polymerase

-host dont ’t have these

• makes rna from an rna templete (needs rna virus)

reverse transcriptase

• host does not have

• makes dna from rna templete

key - double starnded rna (dsrna) virus

• must bring RdRp because human host cells cannot directly read dsRNA into mRNA

lytic cycle

virus enters, makes copies, pops host cell

lysogenic cycle

virus hides dna inside host chromosomes as prophage until triggered to pop out

sars - cov -2

uses spikes protein to bind the host ACE2 receptor

HIV

uses gp120 to bind cd4 receptors uses reverse transcriptase to make dna, and integrase to insert into host dna

prions

infectious proteins with no dna or rna thay force normal proteins to misfold

vertical gene transfer

parent cell passes dna down to daughter cells division

horizontal gene transfer

passing dna sideways to a neighbor cell

transformation

-hgt

-cell takes in naked dna from enviornment using com ea / ec proteins

-cell must be competent

vesiduction

-hgt

-cell takes in tiny lipid membrane bubbles (vesicles) packed with dna

conjugation

-hgt

- direct cell-to-cell contact

-donor (f+) uses sex pilus to send a plasmid to a recipient (f-) from via rolling circle replication

---

hfr strain - f plasmid is glued directly inside main chromsome so it drags host genes along during transfer

transduction

-hgt

-virus accidentally carries bacterial dna from one host to another

generalized (transduction)

phage randomly chops up and packages any piece of bacterial dna

specialized (transduction)

lysogenic phage excises imprecisely carrying only adjacent host genes

homologous recombination

integrating foreign dna into the host chromosome by matching similar sequences

operon

a cluster of genes controled trogether

promoter

rna polymerase landing strip

operator

repressor parking spot and structual genes

repressible operons

(trp operon) usually on, when tryoptophan is plentiful, acts as a corerepressor to stick the repressor onto the operator and turn trnascription off

inducible

(lac operon) usually off, when lactose is present acts as an inducer to pull repressor off an turn trnascription on

qurom sensing

bacteria talk to each other using secreted chemical signal molecules called autoinducer

when cell density high, autoinducers build up, reenter cell, and bind activtor proteins to switchgroup behaviors

pasive trnasport

solute floats down concentration gradint

• not atp

abc transporters

active transport powered directly by atp hydrolysis

symporters (contrancporters)

move 2 thins in same direction

antiporters (contrancporters)

move 2 things in opposite direction

group translocation

chemically alters incoming molecule so glucose keeps diffusing inside

siderophores

special molecule secreted to grab onto tightly bound iron and pull into cell

sec system

moves unfolded proteins across inner memebrance using sce a, yeg and atp

tat system

moves fully folded proteins using proton motive force

1 step (outer membrane secretion)

shoot proteins straight across both membranes at once

2 step (outer membrane secretion)

push proteins into periplasm first

energy source

photo - light

chemo -chemicals

electron source

organo - organic molecule

litho - inorganic molecule

carbon source

auto - fixes co2 gas into food

hetero - eats organic carbon food

aerobic respiration

uses electron transport chain with oxygen as final electron receptor

anaerobic respiration

uses etc with non oxygen inorganic acceptor

fermentation

no etc, pyruvate accepts electrons from nadh to regenerate nad+ making end product like lactate or ehtanol

methanogens (archea)

make methane from co2 and h2

methanotrophs

eat methane as their energy and carbon source

rubisco

key enzyme in calvin cylce fixes co2 gas into organic carbohydrates

microbial autotrophs do 50% of all global carbon fixation

NIF - nitrogenase

converts nitrogen gas to bioavaliable ammonia

nitrogen fixation

takes a ton of atp and destroys by oxygen

amo - ammonia monooxygenase

converts ammonia to nitrate = ammonia oxidation

nxr - nitrate oxidoreductase

convert nitrite to nitrate = nitrtie oxidation

nir - nitrite reductase

convert nitrate/nitrite back into nitrogen gas (denitrification)

eutrophication

Excess fertilizer (Nitrogen/Phosphorus) runs off into lakes $\rightarrow$ causes huge algal blooms $\rightarrow$ algae die $\rightarrow$ heterotrophic bacteria eat dead algae and consume all dissolved oxygen $\rightarrow$ creates hypoxia (dead zones where fish suffocate)

acid mine drainage

Chemolithotrophic sulfur/iron-oxidizing bacteria eat exposed mine minerals, producing sulfuric acid that turns streams red/acidic