bobby
Forum Guru
Topics: 136
Posts: 569
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An investigator has isolated a bacterium that, in the absence of glucose, constitutively produces the proteins coded for by the lac operon. Which of the following statements explains this observation?
A)the promoter has a mutation that prevents RNA polymerase from binding
B)there is missense mutation in the gene for beta-galactosidase
C)the gene for the catabolite activator protein is mutated and inactive
D)there is a mutation in the attenuator sequence
E)the gene for the repressor protein is mutated and inactive
please explain your answer, thanx
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| krsma
Forum Elite
Topics: 40
Posts: 227
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E
if no repressor protein --> nothing stopping Lac Operon from expression
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| bioguy
Forum Guru
Topics: 36
Posts: 677
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http://www.prep4usmle.com/forum/thread/70314/
somewhat related question, please answer
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| sigh
Forum Senior
Topics: 15
Posts: 152
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E
If proteins are constantly produced in absence of glucose then we can think about 3 possibilities:
1-repressor is absent
2-repressor can't bind to operator
3-operator is defective
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