Module 5 Flashcards
bacterial virulence attributes often transfer from one bacterium to another by exchange of what three types of DNA
- chromosomal DNA
- plasmid DNA
- transposon DNA
acquisition of strain resistance is most often by ___ in bacterial DNA
mutations
what are 2 of the 3 major molecular targets for antimicrobials
- bacterial replication
- gene expression
bacterial DNA is present on ____ chromosomes with ___ and potentially ___
- circular
- transposons
- plasmids
bacteria lack a nucleus but their genetic information is present in a _____ within a cell
nuclear region
nonspecific proteins are ___ but have no ___
associated, histones
what occurs since there is no nuclear membrane
SIMULTANEOUS transcription and translation
plasmid DNA replication with ___
two replication forks
replication of bacterial DNA occurs by ___
DNA polymerases
T / F plasmids can be exchanged between strains of bacteria
True
plasmids have protein coding regions that include:
- colonization factors
- virulence determinants
- antibiotic resistance
- conjugation pili
- entire metabolic pathways
what contributes to the pathogenicity of many species
plasmids
plasmids sharing a region readily join together by ____ and what is it called
- cross-over homologous recombination
- Campbell recombination
what are mobile genetic elements
transposons
transposons always encode ___ enzyme integration into a chromosome target site, with or without additional gene(s)
recombinases
T/F transposons can move to plasmid and back possibly inactivating an existing gene
true
some transposons contain genes coding for bacterial surface pili allowing them to __
move between cells
what are the 3 major processes in maintenance and expression of bacterial genetic information
- REPLICATION of bacterial chromosomal & plasmid DNA
- TRANSCRIPTION of bacterial genes
- TRANSLATION of bacterial mRNAs
what is DNA synthesis by DNA-dependent DNA polymerases
replication
what is mRNA synthesis by RNA polymerases on a DNA template
transcription
what is protein synthesis by ribosomes with tRNA and associated factors
translation
__ & __ of bacterial genes are central in colonization, virulence, & pathogenicity
presence & expression
what are secreted biologically active components used for attachment & adhesion
cell walls, toxins, flagella, pilli/fimbriae
how does RNA polymerase initiate transcription of bacterial DNA regions into RNA
recognizes the promoter region
what is a sequence in the DNA that binds RNA polymerase
a promoter
bacterial mRNAs are different than eukaryotic mRNAs in that
about half encode more than one protein
what type of mRNAs have multiple ORFs and are only seen in bacteria
polycistronic mRNAs
what type of mRNAs have a single ORF
monocistronic mRNA
what is a bacterial operon
a 3 protein coding region
what is the first gene ever identified that allows lactose fermentation
lac operon
what is a unit of controlled gene expression
a gene
___ is the HERITABLE gene
RNA coding region
when do ribosomes begin translating mRNAS
as they are being made
what are prokaryotic ribosomes that translate mRNA
polysomes
a ribosome is a ___ complex
ribonucleoprotein
what is the role of a ribosome
the assembly of amino acids into proteins
what are the 3 ways bacteria are able to exchange DNA
- transformation
- transduction
- conjugation
what is the term for when cells take up naked DNA? this occurs in VERY FEW bacteria
transformatipn
what is the term for when phages carry host DNA? this occurs in MOST bacteria
transduction
what is the term for when cells mate through specialized appendages? this usually occurs between SAME SPECIES
conjugation
what allows for the spread of virulence genes and/or antibiotic resistance genes
DNA recombination & genetic transfer in bacteria
what are the steps of transformatin
- The bacterial cell lyses and the bacterial DNA goes directly into the environment
- the naked bacterial DNA is then susceptible to DNAses
- that naked bacterial DNA is then encoded into another bacterial cell
what is a virus that attacks bacteria and replicates by invading a living cell and using the cell’s molecular machinery
bacteriophage
what are bacteriophages composed of
DNA & proteins
what are the 2 types of phages
- virulent / LYTIC phages
- temperature / LYSOGENIC phages
what type of phages interact with RNA & DNA
virulent / LYTIC phages
what type of phages interact with only DNA
temperate / LYSOGENIC phages
what type of phage is involved in infection of susceptible bacteria always leading to destruction of bacterial cells & release of new infectious phages
virulent / LYTIC phages
what type of phage is dependent on growth conditions and can either lyse the host or they can integrate into the chromosome
temperature / LYSOGENIC phages
T/F lysogenic phages can ‘go lytic’ when growth conditions change
true
what is the transfer of F plasmid DNA from F+ (plasmid-positive) donor cell to F- recipient cell
bacterial conjugation
what is the F plasmid that is excised from HFR chromosome and carries new regions
F-prime donor
___ is known to cause resistance to spread quickly through entire Gram - populations
plasmid mediated conjugation
what is a bacteria that has the F plasmid integrated into their DNA
Hfr+ = high frequency recombination
what is an irregular or club shaped Gram + rod bacteria that causes diptheria
Corynebacterium diptheriae
what does the toxin produced by C. diphtheria cause
membrane like coating in the throat by ribosylation of the ribosome
when does C. diphtheriae produce a soluble toxin
when it is encoded by a LYSOGENIC bacteriophage
what is homologous recombination?
a - recombination between two DNA helixes that are aligned over shared sequence (>400 bp)
b - integration of one circular DNA into another
c - fusion of two similar kinds of bacteria into a novel new form
d - method to introduce genes into bacteria for production of useful proteins
a - recombination between two DNA helixes that are aligned over shared sequence (>400 bp)
which one of these is NOT a bacterial genetic element?
a - ribosome
b - circular chromosome
c - transposon
d - plasmid
a - ribosome
what is unique about bacterial genes or transcription units compared to those of eukaryotes?
a - they can have more than one protein coding region
b - mutations in the control region of the transcription unit can change gene expression
c - they are read as nucleotide triplets by the ribosome
d - they can be inactivated by transposons
a - they can have more than one protein coding region
what additional capabilities do temperature ( or lysogenic) bacteriophages have compared to lytic phages?
a - ability to do specialized transduction
b - ability to lyse host bacteria
c - ability to change to phenotype of host bacteria
d - tail fibers in addition to head capsid
a - ability to do specialized transduction
