Micro Flash Cards 1st test

Maintain concentration of limiting nutrients

            Provide additional nutrients

            Remove cells and end products

            Number of cells remains constant

            Pure cultures on solid medium form colonies

            Differ in shape, texture, color

            Center of colony no growth

            Edges of colony exponential growth

cloudiness in culture resulting from microbial growth

obligatory but mutually beneficial relationship

one harmed while the other benefits

relationship between two or more organism that benefits them but isnt neccessary for their survivl, produces result that neither could achieve individually

•Obligate intracellular parasites

•Acellular

•Characteristics:

–Contain single type of nucleic acid (DNA, RNA)

–Protein coat surrounding nucleic acid

–Multiply inside living cell using cell’s machinery

–Cause synthesis of specialized structures that can transfer viral nucleic acid to other cells

•Animal, plant, eukaryotes, bacteria

•Host determined by presence of receptor for virus on cell surface

–Virus attaches to receptor to infect

Determined with EM

From 20 nm to 14,000 nm (about 1/3 size of bacteria)

•Capsid – protein coat, capsomers, protection

–nucleocapsid

•Envelope – surrounding membrane, along with capsid, help virus find suitable host cell and enter

–Naked virus – no envelope

•Nucleic acid – ssDNA, dsDNA, ssRNA, dsRNA

•Transcription

–DNA-RNA-Protein

•Reverse transcription

–RNA-DNA-RNA-Protein

–retroviruses

•Reverse transcriptase (RNA-DNA)

•Polymerases (DNA-RNA)

•“Borrow” what else need from host

•Adsorption – attachment, depends on host cell receptor (host range)

•Penetration – endocytosis (whole virus enters), uncoating (remove envelope and capsid, genome enters)

•Uncoating – removal of envelope and capsid

•Synthesis and assembly – make viral parts and put together

•Release – new virions released (virion – intact virus capable of infection)

–Budding or exocytosis

–Cells are intact!

Highest:  Endospores, prions

Elevated temps – microbiocidal

Low temps – microbiostatic

Moist heat – steam, boiling

Dry heat – baking, flame

Long-term storage

  Psychrophiles

preservation

rapid removal of water with vacuum after quick freeze

causes ejection of electrons to form ions

excites atoms to higher energy state, can cause abnormal bond to form

sort by size

great for heat sensitive liquids

doesnt remove soluble molecules like toxins

tinctures:  solutions mixed with alcohol

aqueous:  solutions mixed with water

bad burns, very irritating

phenol coefficient--comapare other chemicals to phenol

phenolics:  microbicidal, fungicidal, most viruses, not very sporicidal

Bactericidal, not sporicidal, some viruses and fungi

advatage:  mild, low toxicity, fast, not absorbed into deeper tissues

only ethyl alcohol and isoproply alcohol useful

50 percent and higher 70 percent the best

light sensitive

forms oxygen free radicals