Ch 9 Bacterial Gene Transfer Flashcards
What is transformation?
Importing free DNA into bacterial cells
What is the importance of transformation?
It gave clue to gene exchange between microorganisms
What is need for transformation to happen?
Competent cells, artificial manipulations (chemical or electrical means)
Why does transformation occur?
Use indiscriminate DNA as food, to repair genomes, and acquire new genes (horizontal gene transfer)
How do gram-positive bacteria transfer DNA?
The transformasome complex
How do gram-negative bacteria transform DNA
They are either competent or become competent
No transformasomes
What is conjugation?
Transfer of DNA from one bacterium to another by cell-to-cell contact
What is oriT used for?
Used during DNA transfer
What is oriV used for?
Used in nonconjugating cells
Which cell is the F+ cell?
The donor cell
Which cell is the F- cell?
The recipient cell
What does an Hfr cell do?
Transfers chromosome parts into recipient cell
What is generalized recombination?
Two recombining molcs. have stretch of homologous DNA sequence
What is site-specific recombination?
Requires very little sequence homology between DNA molcs.
Is RecA important for general or site-specific recombination?
General recombination
True or False: Gene transfer can occur across biological domains
True
What is transduction?
Bacteriophages carry host DNA from one cell to another
What is generalized transduction?
Can transfer any gene from donor to recipient cell
What is specialized transduction?
Can only transfer a few closely linked genes between cells
What does restriction and modification do for the cell when transferring genes?
Restriction cuts off any alien DNA with restriction endonucleases then modification protects the recognition sites
What is CRISPR?
Microbial immune mechanism used to edit genes to turn them on and off and treat diseases
What is transposase?
Enzyme that inverts target DNA
