Microbio ch4

Aerobic respiration

uses oxygen as final electron acceptor, makes lots of atp

anaerobic respiration

doesn’t use oxygen as final electron acceptor, makes fewer atp

anoxygenic phototrophs

very diverse, live in anoxic environment that is exposed to light

what do microbes need for growth

need carbon source, nutrients, water, temperature, pH, oxygen, sunlight, pressure

binary fission

the way microbes reproduce, dividing into two

generation time

time it takes for one generation to grow

growth phases

lag, exponential, stationary, decline phase

lag phase

no growth, microbes are getting used to environment, does not always happen

exponential phase

cells are doubling in a short time period

stationary phase

general nutrients and oxygen make microbes stop growing, cell growth equal cell death

decline phase

the cells stop growing and metabolizing

batch culture

a closed system microbial culture of fixed volume

planktonic growth

growth in suspension of free floating cells

microbial mats

multilayered sheets with different organisms in each layer

biofilms

communities of microorganisms that attach to a surface and can cause infection by clumping

quorum sensing

a way that microbes communicate amongst each other

psychrophile

can grow in 4 C

mesophile

can grow in 39 C

thermophile

can grow in 60 C

hyperthermophile

can grow in 106 C

acidophiles

have ph below five

neutrophiles

have ph between five and nine

alkaliphiles

have a ph above five

halotolerant

can grow and tolerate up to ten percent salt

nonhalotolerant

can grow and tolerate up to one percent salt

osmophiles

live in environments high in sugar

xerophiles

able to grow in very dry environment

microaerophile

can grow in low levels of oxygen, mostly use anaerobic respiration and fermentation

obligate aerobe

requires oxygen, uses aerobic respiration

facultative aerobe

oxygen not required but grows better with oxygen, uses aerobic, anaerobic, or fermentation respiration

aerotolerant anaerobe

oxygen not required, uses fermentation

obligate anaerobe

oxygen is harmful, only uses anaerobic respiration and fermentation

why is oxygen toxic

o2 is not toxic, exposure to oxygen produces toxic byproducts like superoxide anion, hydrogen peroxide, hydroxyl radical

hydrogen peroxide

has enzyme catalase which causes bubbling, can kill microbes, helps to differentiate between staph and strep

hydrogen peroxide and staph and strep infections

staph is positive for catalase and bubbles, strep is negative for catalase and will not bubble

sterile

has no microbes at all

aseptic

to prevent contamination

pasteurization

beneficial microbes are left inside and bad microbes are killed

autoclaving

sterilizing at 121 celsius for 15 min at 15 psi

UV light

causes thiamines to dimerize, does not penetrate paper or plastic

gamma radiation

can penetrate medical equipment or packaging materials, breaks the backbone of dna

filtration

for sterilizing liquids, need to control the size of pores the material goes through

bacteriostatic agents

inhibit important biochemical processes and bind weakly

bactericidal agents 

bind tightly and kills the cell without lysis 

bacteriolytic agents

kill cell by lysis

sterilants

a chemical completely eliminates all microbes

disinfectants

chemical controls microbes on surface, example is 10 percent bleach

sanitizers

heat and water used to kill microbes on personal care products

antiseptics 

chemicals safe to use on skin or living surfaces, example is 70 percent bleach and h2o2

broad spectrum antibiotics

lots of bacteria are controlled

narrow spectrum antibiotics

only used for certain types of bacteria

cell membrane as drug target

penicillin can target cell walls and peptidoglycan in bacterial cells, polymyxin treats pink eye

protein synthesis as drug target 

antibiotics targeting protein synthesis will target translation by binding to the bacterial ribosome

protein synthesis drugs

tobramycin treat eye, doxycycline treat internal surgery, erythromycin is protein synthesis inhibitor

nucleic acid synthesis as drug target

affects the dna gyrase or packaging of dna, ciprofloxacin treats pneumonia, rifampin treats tb

isoniazid

a growth analog effective against mycobacterium by interfering with synthesis of mycolic acid

antivirals

target host structures

nucleoside analogs 

commonly used antivirals which block reverse transcriptase and production of viral dna 

antifungals

fungal infections are topical infections usually treated with creams