Monday, August 23, 2010

How conjugation provides greater diversity among bacteria ??????????????????please helpp !!! really badly!!?

please helpp !!! really badly need in help !! and please answer

How conjugation provides greater diversity among bacteria ??????????????????please helpp !!! really badly!!?
Conjugation occurs when bacterial cells come in contact and exchange portions of their DNA molecules. Thus, one bacterium can change when there is a change (or exchange) in DNA.





This switching of genes is comparable to what occurs during Prophase I of meiosis. During Prophase I, chromosomes appear and the chromosomes that are the same size and shape and responsible for the same traits (one had its origin in the mother and one of the pair came from the father and are called homologous chromosomes) pair up and a similar event occurs. In this case it is called crossing over and groups of genes from one chromosome will switch to the other member of the pair.





Bacterial conjugation, like crossing over, mixes up the genes and the gene pool and leads to diversity within the species.
Reply:Normally bacteria "reproduce"by binary fission..which literally means to "break into 2". A mother cell will divide into two IDENTICAL daughter cells....these will also divide to produce 2 IDENTICAL daughter cells. So while this method is rapid and produces lots of bacteria, the result is that they will be all ( almost) identical in their genetics.....this means they will respond in the same way in how virulent ( how "nasty"the disease they produce ) may be, how they respond to antibiotics, in that they may be all resistant or all suseptable to one/many antibiotics, etc."This type of reproduction is considered to be assexual reprodution where there is only 1 parent and offspring are identical to the parent.





In certain cases, bacterial will reproduce by conjugation, which is the equivalent of sexual reproduction..where there are 2 parents and the DNA of both are combined. The result is genetically different offspring. This means that the new combinations of genes in the new bacteria oofspring may make them resistant to antibiotics ( or less resistant..its just the luck of the draw)....it could make them more virulent than either parent ( or less)...it allows there to be more vairation i( genetically speaking) and this is considered to be better as most plants and animals reproduce very successfully this way. It gives rise to "new"traits etc much more quickly than assexual reproduction ( binary fisson in this case) and these CAN benefit the bacteria greatly if they are the right combination of genes.


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