exam 4

photo autotrophs

uses light for energy

uses co2 for carbon

cyanobacteria, plants ,algae

Chemo heterotrophs

carbon and energy from organic compounds

animals, fungi, protozoa, most bacteria

binary fission

one cell divides into two identical cells

generation time is the time for one cell to divide

psychrophile

below 15 Celsius cold

rivers mountains streams snowfields

Mesophile

the human body in the middle of both cold and hot moderate temp

thermophile

above 45 Celsius hot springs volcanos sunny

obligate aerobe

use o2 in metabolism

requires oxygen

obligate anaerobe

cannot use o2 in metabolism

damaged by oxygen

facilitative anaerobes

can grow with or without oxygen

minimum PH

lowest pH where growth is permitted

maximum PH

Highest pH where growth is supported

optimum PH

the PH that permits the fastest growth and metabolism

selective media

grows certain microbes but not others

differential media

a type of selective media that allows easy identification of microbes

distinguishes based on metabolic traits

complex media

chemical composition varies

supports a variety of microbes example agar agar

synthetic media

exact chemical composition kown

exponential growth

population size doubles each generation (each division adds

increases rapidly two new cells)

growth curve

1. lag phase- no increase in number of living bacteria cells

2.log phase- exponential increase in number of of living bacteria cells

3. stationary phase-plateau in number of bacteria cells rate of cell division and death equal

4. death phase- exponential decrease in number of bacteria cells

sterilize

to kill all microbes in area

all endospores must be killed

disinfect

kills 99.9 percent of pathogens (impractical for humans)

not reliable for spores (used on inanimate surfaces)

chemicals like bleach phenolics

doesnt sterilize

Sanitization

disinfect inanimate objects used by the public

useful for dishes plates basic cleaning

steam/autoclave

121 C at 15 psi

uses pressure and steam to sterilize

not useful for heat sensitive materials

denatures proteins

refrigeration/freezing

-Biostatic (does not kill)

-Cannot sterilize

membrane filters

mechanical removal of cells or spores

can sterilize heat sensitive materials

smaller the agent harder to filter

heat

denaturizes proteins

1. boiling water(moist) - doesn't kill all endospores doesnt sterilize

dry heat(flaming, ovens) takes longer than moist heat sterilizes

Pasteurization

doesn't sterilize used on food

reduces microbial preserves nutrients

used on milk

Sepsis

growth of microbes in blood/tissue

causes infection

asepsis/aseptic technique

practice used to prevent pathogens

keep equipment sterile

antiseptic

reduces microbes on living tissue

chemicals methods applied to skin

alcohol and iodine

degerming

physical removal of microbes from surface

involves scrubbing or washing

osmotic pressure

high concentration of salt and sugar

fungi is more resistant

dehydrates microbes stops growth

static vs cidal

static inhibits growth

cidal kills microbes

heavy metals

denaturizes proteins

doesn’t sterilize

mercury, sliver, zinc, copper gold

surfactants

reduces attraction between molecules

soaps(polar lipids)

detergents(charged organic surfactants)

degerming and sanitization

alcohols

dehydrates disinfects, antiseptic is diluted with water

ethanol or isopropanol

doesn’t sterilize , toxic

phenol

carbolic acid

destroys enzymes

bad odor irritate human tissues

halogens

oxidize cell structures

iodine antiseptic for skin cant sterilize

chlorine for water treatment disinfection

can sterilize

oxodizer

(hydrogen peroxide)

oxidizes enzymes

great disinfectant not good antiseptic

high concentration sterilizes

aldehydes

can sterilize

disrupts enzymes and DNA

odor unstable carcinogenic

metabolism

(folic acids)

sulfa drugs

plasma membrane

polymyxin

cell wall

penicillin

B lactams

Bacitracin

DNA and RNA synthesies

cipro rifampin

fluoroquinolones

ribosomes

affects protein synthesizes

streptomycin (aminogylacide)

(tetracycline) (chloramphenicol)

antibiotics

chemicals that kill or inhibit microbes

produced naturally by fungi bacteria

kills pathogen without damaging host(selective)

risk bacterial resistance to people

ionizing vs non ionizing

ionizing damages DNA sterilizes (xrays, Gamma radiation)

nonionizing uv radiation disinfects doesn’t sterilize

gases

sterilizes items that cant be heated or irradiated

disrupts DNA and enzymes

slow action carcinogenic

antiviral drugs

chemotherapy

using chemicals to treat relieve or prevent disease

antiviral drugs

blocks viral entry, inhibits viral assembly and nucleic acid

hard to treat use host cell machinery(selective toxicity)

Acyclovir → herpes virus → blocks DNA replication

AZT → HIV → blocks reverse transcriptase

Tamiflu → influenza → prevents viral release