Plasmid types


Are conjugative plasmids and the F factor(plasmid) the same thing? Or is the f factor a type of conjugative plasmids which also include the R factor. Does the r factor also have genes for encoding pili and do all conjugative plasmids code for pili?Im confused because the book classified plasmids in two ways:according to transfer ability and according to functions. And they explained how bacteria containing the f factor could transfer antibiotic resistance. And in the classification they said that the r factor has genes for antibiotic resistance.What is the relation between the f factor, r factor and conjugative plasmids? Also are stringent and relaxed plasmids the same as conjugative and nonconjugatuve plasmids? Im so confused pleaseeee help.

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Microbiology 2019-10-05T19:59:10+00:00 1 Answer 445 views New Member 0

Answer ( 1 )

    • F factor and R(fi+) factor have same sex pilli and the ability of R(fi+) factors to control genes of F factor tells that F factors and R(fi+) factors are quite related to each other. But both of these are different in episomal characteristics. F factor has information for the restriction phages φII T7.R factors are sensitive to both of these restriction phages . R(fi+) factor does not stop the F factor in cells containing both an R(fi+) factor and an F factor. Both of these are heteroimmune episomes. In addition, an R(fi+) factor in cells containing both an R factor and an F factor can not completely stop the expression of F-factor.
    • The relaxed plasmids are known as the best cloning vectors with high copy numbers, which is estimated as 50 copies per cell.The replication of relaxed plasmids is not associated with the chromosomal replication. Relaxed plasmids are non-conjugative.
    • The replication of stringent plasmids is associated with the chromosomal replication. Stringent plasmids are conjugative

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