bluestar
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a bacteria harboring a 15000 base pair plasmid that encodes resistence to tetracycline and ampicilline segregates mutants that lose resistance to either drug. Each independent mytant plasmid appreas to increase in size by approximately 5200 bp. which molecular even best explains these findings?
a, formation of plasmid concatemers
b, formation of pyrimidine dimers
c, homologous recombination
d, insertion of a tranposon
e, slip-stranded DNA replicaiton errors
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| deea
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I guess it's E - i ruled out b,c and d but i don't have any ideea what plasmid concatemers are....
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| dariush
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i`d go for E too but what is CONCATEMER anyway?
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| bluestar
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I have no idea about this question. Could you guys please explain why it's E?
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| Ahab
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Insertion of a transposon that interferes with the genes that provide antibiotic resistance.
My reasoning is that I would find it unlikely that a plasmid would increase in size by 33% through errors alone more likely insertion of extra genetic material through a transposon?
At least thats how I would approach the question in an exam
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| deea
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I thought of that... but why should it loose the resistance to both antibiotics... a transposon should bring resistance genes. My resoning is: if the transposon inserts in the middle of one of the resistance genes and splits the gene it so that it loses the properties (forms a recombinant plasmid), the plasmid should retain the gene for resistance to the other antibiotic.
About the other choices - b and c would not increase the size of the molecule.
I don't know what a is.. so the discussion is between d and e.
BUT I am not very clear about this question eather... so please Bluestar tell us the correct answer!!!!!!
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| dariush
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i change my position now! it is most likely d !!!!
Deea, if you go through the Q carefully it says "EITHER DRUG" not BOTH. meaning that Transposons may have interrupted TETRA gene in one part of the population and AMP gene in the rest. i think that makes sense.
but still what is CONCATEMER anyway??
does anyone know ? please tell us !
Bluestar what is the true answer to this Q? we all keep are fingures crossed 
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| bluestar
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Sorry I don't have the answer for the question.
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| adeelmd
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I am just guessing, but couldn't a concatemer mean a combination of more than one plasmid (like 2 or three plasmids fused)...what are slip stranded dna errors??? I am also Guessing that it has someting to do with single strand errors ..... I pick D cuz at least i can explain the logic behind it....
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| dariush
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i just Quot from a site :
" Concatemer: Multiple copies of a DNA sequence arranged end to end in tandem. Concatenate means to link together in a chain or in a series."
does anyone know what is it`s application or function? let us know please!
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