Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
The structure of bacterial chromosome in maintained by what?
|
polyamines.
|
|
|
Bacteria may contain what extrachromosomal elements?
|
plasmids and bacteriophages.
|
|
|
What is an episome?
|
an integrated plasmid.
|
|
|
What are the two infection states of bacteriophages?
|
lytic and lysogenic.
|
|
|
Transposons transfer DNA where?
|
WITHIN a bacterial cell; from one position to another in the genome, from one molecule of DNA to another. (Like from plasmid to plasmid or plasmid to chromosome.)
|
|
|
insertion sequences of transposons
|
150-1500 base pairs, inverted repeats at both ends, contain minimum information needed for gene transfer.
|
|
|
complex transposons often carry what?
|
information beyond what's needed for gene transfer. e.g. resistance to antiinfectives.
|
|
|
Conjugation
|
mating, transfer of info is one way-donor to recipient;
|
|
|
F carries what?
|
genes for its own transfer, including the genes for sex pilus, If F carries a fragment of the bacterial chromosome, then that plasmid is the F' plasmid.
|
|
|
If F' integrates into the chromosome, the recipient of integration is called?
|
Hfr, high frequency recombination cell.
|
|
|
What is the mechanism of DNA transfer in conjugation?
|
single stranded molecule, plasmid encoded protein makes site specific nick at OriT, nick starts rolling circle replication, displaces linear strand directed to F- cell, once in cell complimentary strand synthesized, recipient cell becomes male.
|
|
|
Transformation
|
bacterial cells take up fragments of naked DNA, incorporate fragments into their genomes; ability to take it up is called competence; natural in some bacteria but can me made to happen in all with ions and electroporation.
|
|
|
transduction-
|
genetic transfer mediated by bacterial viruses; bacteriophages pick up fragments of DNA, package fragments into bacteriophage particles; DNA delivered during infection.
|
|
|
Generalized transduction
|
Selection of random host sequences, accidental packaging of host DNA into bacteriophage.
|
|
|
Specialized transduction
|
transfer of particular genes, usually those adjacent to chromosomal integration site.
|
|
|
recombinant DNA technology
|
purify, amplify, modify, express specific gene sequences.
|
|
|
Cloning and expression vectors
|
must allow insertion of foregin DNA, must maintain ability to replicate in bacterial or eukaryotic host.
|
|
|
Most cloning vectors are engineered to have what?
|
site for insertion of foreign DNA, means for selecting bacteria that have incorporated vector (Like antibiotic resistance marker), means for identifying bacteria that have incorportated plasmids containing inserted DNA>
|
|
|
expression vectors are engineered to have?
|
DNA sequences for replication in bacteria, transcription of gene into mRNA.
|
|
|
DNA sequences can be obtained by
|
purification of DNA, selective amplification by PCR
|
|
|
restriction enzymes
|
cleave at palindromic base sequences, may make staggered cuts, may make blunt cut, multiple cloning site.
|
|
|
DNA ligase does what?
|
joins vector to DNA fragments. result is recombinant DNA
|
|
|
Applications of genetics
|
generation of genomic library; you can either clone all fragments or convert mRNA to cDNA and make a cDNA library.
|
|
|
Medical applications of bacterial genetics
|
insulin, hep b vaccine, human growth hormonone, hep C virus diagnostic,
|
|
|
bacteriophages have been used in the past to identify same strains of bacteria
|
like staph aureus food poisoning episode.
|
