YO PPL! LOL gona b a boring post unless u super duper interested in microbiology!!! hahhahaha sooooooo here goes!!!~~~

OK 1ST IS!!!! sterilization and disinfection!!!!

S: sterilization
Eliminates ALL microorganisms and microbes on or in an object.
Autoclave/ethylene oxide gas
Used 4 sterilizing canned FOOD!!! ,Surgical instruments, culture media

D: disinfection
Eliminates most microorganisms
Alcohol
Disinfects workbenches 4 preparation of culture media

A: antisepsic
Eliminates most microoganisms on living tissue
Alcohol. Iodine(antiseptic)
Prevents infections of open wounds.

P: pasteurization
Eliminates microoganisms, preventing change of taste and nutrients
Heat 4 a short period
Pasteurization of milk and fruit juices etc

how does soap wash away microbes on or hands?
soap molecules hav a fatty end and a ionic end. when mixed with water it creates a suspension when e water binds 2 e ionic end and e oil bind 2 e fatty end. this allows water 2 wash away e microoganisms on our hands.

how does antimicrobials work.
3 types: bacteriostatic, bacteriocidal, bacteriolytic
bacteriocidal kills e living cells.bacteriolytic kills off e cells and destroys them.( seen by total cell count sloping down along with the living cell count in graph)

antifungal drugs.
polyene antibiotics prevent ergosterol in e cell membrane. ergosterol in fungi but cholesterol in humans.
imidazole and triazole inhibit ergosterol synthesizing enzymes, preventing formation of cell membrane.

NEXT OFF IS MICROBIAL ENVIRONMENTAL FACTORS!!!

5: temp, pH, water availability, oxygen, UV light.

with temp: psychrophiles( loves low temp), mesophiles( normal temp), thermolphiles( high temp like duh -_-)

when below minimum temperature, cell membrane has 2 little fluid and so no diffusion/transport of molecules; thus there is no growth.
when at optimum, the diffusion/transport of molecules is e highest and thus has highest growth.
when nearing maximum/above maximum, the high heat denature e cell proteins/membranes causing it 2 lyse/MATI!!!!

with pH: acidophiles, neutrophiles, alkalinophiles. if i need 2 explain these den uhhhh -_-

during bacterial growth:
protein breakdown increases pH.
organic acid production decreases pH
buffers help provide optimum pH 4 growth.

2 types of food poisoning: intoxications and infections
Intoxications: when food is left in e fridge 4 2 long, e bacteria leave toxins on e food, which causes u 2 go @@ if u nvr cook e food well enough b4 eating.
Infections: whereby e bacteria grow in ur digestive tract! ewwwwwwwww LOL

3 types of infections: bacterial, viral, parasitic

salmonella ella ella eh eh under my umbrella is e 2nd most common bacterial infection.
all salmonella inffections are called salmonellosis except 4 an infection by salmonella typh which is called typhoid fever.

salmonella mostly found in raw/undercooked eggs poultry meat fish shellfish such as shrimp BLABLABLABLABLABLABLABLABLABLABLABLABLABLABLA

e most common type of viral infection is hepatitis A. which is due 2 water getting contaminated by raw sewage, shellfish tat r harvested from contaminated water.
foods tat hav been known 2 contain hepatitis A: water, sliced luncheon meat, sandwiches, SALADS( I KNEW VEGES ARE BAD!!!!!!)

parasitic infections: mostly caused by trichinella spiralis which causes u 2 hav trichinosis.
infects pigs bears etc.
we get infected due 2 undercooked pork etc.

NOW E 3RD FACTORS ISSSSSSSSSSSSSSSSSSSSSSSSS WATER AVAILABILITY!!!!!

microorganisms grow in diff water availability.
Halophiles( love high salt conc. )
Osophiles( love high sugar conc.)
xerophiles(love dryness)

how do microbes adapt 2 low water availability?
method1: they pump in inorganic ions such as K+
method 2: they store water soluble molecules such as sucrose.

industrial applications of e above shit:
PCR(polymerase chain reaction)
uses heat stable enzymes found in thermophiles 2 rapidly amplify DNA. process is called taq polymerase. this won Kary mullis e nobel prize in 1993.

Bioremediation: this uses e enzymes from bacteria, algae, plants etc 2 change an evironment tat has been contaminated back 2 its original state. (eg. oil spills)

NEXT ISSSSSSSSSS MICROBIAL NUTRITION AND GROWTH!

life needs : energy, CHNOPS, water 2 survive.

2 types of energy sources: chemotroph and phototroph.
2 types of chemotrophs: chemoorganotrophs and chemolithotrophs.
chemotrophs use chemotrophy 2 get energy from organic/inorganic substances.
chemoorganotrophs use organic substances such as glucose/sucrose etc.
chemolithotrophs use inorganic substances such as H and C
phototrophs use phototrophy 2 get energy from sunlight.

Auto and heterotrophs: autotrophs use CO2 as their source of carbon while heterotrophs use other sources as their carbon source.

OXYGEN!!
aerobes and anaerobes
aerobes need oxygen 2 survive.
anaerobes need 2 hav no oxygen 2 survive
facultaive anaerobes can survive in both
micro aerophiles can survive in regions of low oxygen conc.

obligate and facultative
obligate: must have either oxygen/ NO oxygen at all 2 survive
facultative: flexible

why obligate anaerobes canot survive in oxygen?
oxygen changes in2 molecules in cells:
superoxide free radical: O2-
hydrogen peroxide: H2O2
hydroxyl radical: OH.

these molecules can take electrons from cell proteins etc. therefore cell will die.
aerobes can survive due 2 e presense of superoxide dimutase(SOD) and catalase.
superoxide dismutase converts superoxide free radicals in2 hydrogen peroxide and O2
catalase converts H2O2 in2 water and oxygen.

GROWTH GRAPH
consists of : rest, lag, exponential, stationary, death phases.
lag phase: synthesis enzymes, cell repair, change of cell chemistry, germination from rest phase.
exponential: cells divide rapidly.
Stationary: some cells start 2 die. (accumulation of wastes/lack of food/compt 4 food)
death: more cells mati-ing den XXX-ing and so less cells. mati-ing due 2 e loss of ability 2 detoxify toxins as wastes accumulate. food running out.

Culture media: 2 types
synthetic and nonsynthetic.
synthetic has known ingredients and amounts.
nonsynthetic has unknown amounts and ingredients

Calculation of growth: Nf= Ni(2^n)
where Nf is final cell number
Ni is initial cell count
n is number of generations

2 calculate n, times the time allowed 2 grow with time taken 2 undergo binary fission once.

measuring microbial growth:
cell numbers: viable and total
cell mass

viable: spread and pour plates

spread plates: culture is pipetted on2 media and spread evenly. incubate and den count number of colonies.
Advantages counts living cells only
disadvantages: strictly 4 aerobes. microbes diffuse and colonies may overlap.

Pour plates: culture is pipetted on2 petri dish. media is poured in and mixed well with culture. incubate and then count.
advantages: counts living cells only.
disadvantages: strictly 4 anaerobes only, colonies are smaller as movement is restricted and counting is difficult.

Cell mass: centrifuge and filtraion

centrifuge:
pour culture in2 centrifuge tube and centrifuge. pour off top layer. and add in distilled water. centrifuge agn. pour off top layer agn. dry e tube and weigh e cells left bhind.

filtration:
weigh e filter paper. pour in a known amount of culture. wash filtrate with distilled water. let it dry.

filtration is more accurate den centrifuge.

DWAN TYPE LIAO!!! HAND IS SUPER E TIRED!!!! ARGHHHH