Module 8 Lec 2 Flashcards
What is natural transformation in bacteria?
Natural transformation occurs when a recipient cell has the enzymatic machinery to import DNA from its environment.
What is artificial transformation in bacteria?
Artificial transformation involves damaging the recipient cell walls, allowing donor DNA to enter the cell.
How are cells made competent for transformation?
Cells are made competent by treating them with calcium at cold temperatures, which increases their ability to take up DNA.
What is electroporation in bacterial transformation?
electroporation is the process of mixing donor DNA with recipient bacteria and subjecting them to a brief high-voltage shock, which opens up the cell membrane to allow DNA uptake.
What is the result of conjugation between an F+ and F- cell?
After conjugation, the F- cell becomes F+ and can now act as a donor in future conjugations.
How does the F-plasmid facilitate conjugation?
The F-plasmid codes for a pilus (a tube-like structure) that allows the F+ cell to connect with the F- cell and transfer the plasmid DNA.
What happens when an F+ bacterium conjugates with an F- bacterium?
During conjugation, the F+ cell transfers a copy of the F-plasmid to the F- cell, turning it into an F+ cell.
What is the F-plasmid in bacterial conjugation?
The F-plasmid (fertility plasmid) carries genes that allow a donor bacterium (F+) to transfer DNA to a recipient (F-) during conjugation.
What is conjugation in bacteria?
Conjugation is the transfer of genetic material between two bacterial cells through direct contact, typically involving a pilus.
What does Hfr stand for in bacterial conjugation?
Hfr stands for High Frequency Recombinants, which are bacterial cells with the F-plasmid integrated into their chromosome.
What happens when an Hfr cell conjugates with an F- cell
During conjugation, the Hfr cell transfers part of its chromosomal DNA (including the F-plasmid) to the F- cell. However, the full F-plasmid is rarely transferred.
How is an Hfr different from an F+ cell?
An Hfr cell has the F-plasmid integrated into its chromosome, while an F+ cell carries the F-plasmid as an independent plasmid.
What is a key feature of Hfr conjugation?
In Hfr conjugation, the chromosomal DNA is transferred along with the F-plasmid, but usually not all of it. This results in genetic recombination in the recipient cell.
Can an F- cell become an F+ cell by conjugating with an Hfr cell?
No, because Hfr conjugation typically does not transfer the full F-plasmid to the F- cell, so the F- cell does not become F+.
What is the basic process of conjugation involving Hfr?
Hfr conjugation involves the transfer of chromosomal DNA from an Hfr cell (a bacterium with the F-plasmid integrated into its chromosome) to an F- cell (a bacterium lacking the F-plasmid).
