HOW IS F plasmid formed in recipient bacteria?

The F plasmid contains only F factor DNA and no DNA from the bacterial genome. F’ (F-prime) bacteria are formed by incorrect excision from the chromosome, resulting in F plasmid carrying bacterial sequences that are next to where the F episome has been inserted.

How are F plasmids transferred?

The F plasmid DNA replicates and the newly synthesized copy of the circular F molecule is transferred to the F− recipient (Figure 9-3c). However, a copy of F always remains behind in the donor cell. The recipient cell becomes converted into F+, because it now contains a circular F genome.

How do bacteria transfer genetic material?

Conjugation is the process by which one bacterium transfers genetic material to another through direct contact. During conjugation, one bacterium serves as the donor of the genetic material, and the other serves as the recipient. The donor bacterium carries a DNA sequence called the fertility factor, or F-factor.

What is an F factor and how does it and other factors like it contribute to gene exchange?

The F factor encodes genes for sexual pili, thin rod-like structures with which F-carrying (male or donor) bacteria attach to F− (female or recipient) cells for conjugative transfer. The F factor carries an operon of about 30 genes, encoding Tra proteins promoting transfer (Figure 1).

What is the difference between F factor transfer and HFr transfer?

In F factor conjugation, only the F factor is transferred to the F- strain; in HFr conjugation, the chromosomal DNA is transferred first, the F factor last.

Can f+ conjugate with F +?

(No, the bacterium still has the F factor, so it cannot be the recipient.) The bacterium is F+, and is the donor. (No, a bacterium with the F factor is not a recipient.) When the F factor is integrated into the bacterial chromosome, it can still act as the donor in a conjugation cross.

What kind of bacteria are rod shaped?

Bacillus, (genus Bacillus), any of a genus of rod-shaped, gram-positive, aerobic or (under some conditions) anaerobic bacteria widely found in soil and water. The term bacillus has been applied in a general sense to all cylindrical or rodlike bacteria.

What is the difference between F factor transfer and Hfr transfer?

Is the F fertility factor integrated into the chromosome?

The F fertility factor is integrated into the chromosome in an Hfr strain, is free in the cytoplasm in an F+ strain, and is missing from an F- strain. In an interrupted-conjugation experiment in E. coli, the pro gene enters after the thi gene.

What is the Order of these markers on the circular chromosome?

In E. coli, four Hfr strains donate the following markers, shown in the order donated: Strain 1: M Z X W C Strain 2: L A N C W Strain 3: A L B R U Strain 4: Z M U R B All of these Hfr strains are derived from the same F+ strain. What is the order of these markers on the circular chromosome of the original F+?

How is the F + A + genotype produced?

In Figure 5-15, how is the F+ a+ genotype produced? A cross is made between two E. coli strains: Hfr arg+ bio+ leu+ × F- arg- bio- leu-. Interrupted-mating studies show that arg+ enters the recipient last, so arg+ recombinants are selected on a medium containing bio and leu only.

What are donor genes being selected on each type of agar?

The cells are then plated on agar of the following three types, where nutrient Aallows the growth of a−cells; nutrient B, of b−cells; nutrient C, of c−cells; and nutrient D, of d−cells (a plus indicates the presence of streptomycin and a nutrient, and a minus indicates its absence): a. What donor genes are being selected on each type of agar? b.