Table of Contents
- 1 What happens when an HFR cell conjugates with an F cell?
- 2 When an F+ cell donates to an F cell What is transferred?
- 3 What happens when F+ mates with F?
- 4 How is FF XF conjugation different from Hfr XF?
- 5 How do f+ cells differ from F cells quizlet?
- 6 What happens after the cross between Hfr cell and F- Cell?
- 7 What is the frequency of F-factor transfer from donor to recipient cell?
What happens when an HFR cell conjugates with an F cell?
Hfr cell acts as donor while F- cell acts as recipient. After the cross between Hfr cell and F- cell, recipient cell remains recipient. In this conjugation, chromosomal DNA is always almost transfer from donor to recipient cell together with portion of F- factor. So, frequency of recombination is high.
What is the end result of Hfr conjugation?
In conjugation mediated by Hfr cells, transfer of DNA starts at the origin of transfer (oriT) located within the F factor and then continues clockwise or counterclockwise depending on the orientation of F factor in the chromosome. This results in sequential transfer of genes on the bacterial chromosome.
When an F+ cell donates to an F cell What is transferred?
In conjugation, DNA is transferred from one bacterium to another. After the donor cell pulls itself close to the recipient using a structure called a pilus, DNA is transferred between cells. In most cases, this DNA is in the form of a plasmid. An F+ donor cell contains its chromosomal DNA and an F plasmid.
How does an F+ cell differ from HFR cell?
The key difference between F+ strains and Hfr is that F+ strains have F plasmids in the cytoplasm freely without integrating into bacterial chromosomes while Hfr strains have F plasmids integrated to their chromosomes.
What happens when F+ mates with F?
The bacterium is F+, but is now the recipient. When the F factor is integrated into the bacterial chromosome, it can still act as the donor in a conjugation cross. These integrated strains are called Hfr, because of the high frequency of recombination that occurs when mated with F- bacteria.
How do an HFR cell and an F+ cell differ?
How is FF XF conjugation different from Hfr XF?
Only F+ x F- conjugation requires a pilus. Only Hfr x F- conjugation transfers genes from the bacterial chromosome. 2.
How do HFR cells differ form from F cells quizlet?
How does an F+ cell differ from an Hfr cell? Hfr strains have the F plasmid integrated into the chromosome. Ability to synthesize sex pili, presence of a fertility factor, and ability to mate with an F- cell.
How do f+ cells differ from F cells quizlet?
How does an F+ cell differ from an Hfr cell? F+ cells have no plasmids. Hfr cells cannot perform conjugation. Hfr strains can no longer reproduce.
What is high frequency recombination (HFR) bacteria?
When F-plasmid (sex factor) integrated with chromosomal DNA then such bacteria is known as high frequency recombination (Hfr) bacteria. In the cross (conjugation) between Hfr cell and F- cell, frequency of recombination is very high but frequency of transfer of whole F-factor is very low. Hfr cell acts as donor while F- cell acts as recipient.
What happens after the cross between Hfr cell and F- Cell?
After the cross between Hfr cell and F- cell, recipient cell remains recipient. In this conjugation, chromosomal DNA is always almost transfer from donor to recipient cell together with portion of F- factor. So, frequency of recombination is high.
Why is conjugation not possible with HFR and F+?
This conjugation will not happen because neither Hfr nor F+ cells can be recipients. Recipient cells in conjugation must be F-.
What is the frequency of F-factor transfer from donor to recipient cell?
So, frequency of transfer of whole F-factor is very low. After the cross between Hfr cell and F- cell, recipient cell remains recipient. In this conjugation, chromosomal DNA is always almost transfer from donor to recipient cell together with portion of F- factor.