MBIO 2020: Lab Final Exam

alcohol

if culture is spilled onto skin, first wash with ___, then with soap and water

water

contamination of the mouth should be treated with copious amounts of rinsing with ___

rubbing

avoid ___ eyes that have been splashed with culture

disinfectant

clothes that have been contaminated should be disinfected with a small amount of ___, then allowed to dry completely

detergent and bleach

contaminated clothes and lab coats should be washed separately from other clothes with ___

compressed gas

flammable

oxidizing hazards

death / toxicity

health hazard

harmful / irritant

biohazardous infectious materials

corrosion

exploding bomb

UV

we exposed our bacteria to ___ in order to trigger induced mutations

30-300

a reasonable amount of colonies when counting colonies on plates

cfu/ml

# of colonies counted on plate / amount of sample added to plate

concentration of cells in original sample

cfu/ml of diluted sample / dilution of that plate

mutation frequency

cfu/ml of mutants / cfu/ml of control plates

rifampicin

antibiotic that acts by binding to the beta subunit of RNA polymerase and inhibits RNA synthesis since RNA won’t be able to bind to DNA

auxotroph

mutant strain that has lost its ability to synthesize one or more essential nutrients

growth factors

essential nutrients needed for the growth of bacteria; can be produced by wild-type strain in minimal media

trp operon

if tryptophan is absent from the environment, E. coli uses the ___ to synthesize tryptophan

carbon source mutant

strain that has lost its ability to use a carbon source that would normally be used by the wild-type

lac^- mutant

carbon source mutant that is incapable of using lactose; will not grow if lactose is the only carbon source in the media

• lac operon is defective

genotype

phenotypes are dependent on ___

sensitive

the strain of bacteria has a gene that means it will not survive in the presence of the antibiotic

resistant

the strain of bacteria has a gene that means it will survive if exposed to the antibiotic

+ superscript

means that the gene is present and working normally

- superscript

means that the gene is missing or non-functional

defined media

media with all the elements need for growth by wild-type E. coli, but not growth factors and carbon sources

• M9 medium

complex media

media with a wide variety of growth factors and organic carbon sources

• gets carbon and energy through peptones

• gets growth factors from peptones and yeast extracts

• LB agar

Mycobacterium tuberculosis

one of the bacteria (alongside Mycobacterium leprae) rifampicin works against

ampicillin and tetracycline

antibiotics that work on gram negative and positive bacteria

streptomycin

antibiotic most effective against gram negative bacteria

peptidoglycan

ampicillin blocks ___ synthesis by preventing cross-links from forming

30S subunit of ribosome

tetracycline binds to the ___ and prevents the binding of aminoacyl-tRNA to its A site

tRNA

streptomycin binds to the 30S subunit of the ribosome and causes ___ mismatches which results in mistranslated proteins

rifampicin MOR

mutation in the beta subunit prevents the drug from binding to RNA polymerase

ampicillin MOR

production of a beta-lactamse enzyme that cleaves the beta-lactam ring which inactivates the antibiotic

tetracycline MOR

organism actively excretes the drug which prevents it from accumulating inside the cell

streptomycin MOR

mutations in rpsL gene (which codes for a 30S ribosomal polypeptide) result sin reduced binding of the drug

lac operon

a series of genes that regulate the production of beta-galactosidase

beta-galactosidase

the enzyme that breaks down lactose into allolactose

lacI

codes for the repressor protein in the lac operon

lacZ

codes for beta-galactosidase

lacY

codes for lac permease

lac permease

enzyme needed to bring lactose into the cell

lacA

codes for transacetylase

allolactose

inducer of lac operon

cAMP/CAP complex

the binding of the ___ promotes efficient binding of RNA pol and activates transcription of lac operon

import

adenylate cyclase is inhibited by the ___ of glucose

halo

morphology as a result of lysis inhibition caused by secondary adsorption of phage onto already-infected cells

turbid plaque

caused by incomplete lysis of host cells

MOI

multiplicity of infection

high

___ MOI is caused by a high ratio of viruses to bacteria; causes lysogens to form

low

___ MOI is caused by a low ration of viruses to bacteria; causes lysis of bacterial cells

alkaline lysis

method used for isolating plasmid DNA from bacterial cells

steps of alkaline lysis

• bacterial cells lysed

• genomic DNA is denatured by alkaline solution which plasmid DNA remains intact

• neutralization

• centrifugation

centrifugation

step of alkaline lysis method which seperated cellular debris and chromosomal DNA from the plasmid DNA

neutralization

step of alkaline lysis method where genomic DNA is renatured while plasmid DNA remains denatured

GTE buffer

the purpose of ___ in alkaline lysis method is to provide a stable, isotonic environment to suspend your bacterial cell pellet uniformly before lysis begins

RNase A

purpose of ___ in alkaline lysis is to degrade and remove contaminating cellular RNA from plasmid DNA sample