What would happen if there were a mutation in the operator of the trp operon?
If there were a mutation in the operator region of the trp operon, there would be a nucleotide change in the sequence of the operator.
What causes the trp operon to be turned off?
The trp operon is expressed (turned “on”) when tryptophan levels are low and repressed (turned “off”) when they are high. The trp operon is regulated by the trp repressor. When bound to tryptophan, the trp repressor blocks expression of the operon.
What would be the most likely effect of a mutation in the operator of a lac operon?
What would be the most likely effect of a mutation in the operator of a lac operon? The genes would be constitutively expressed.
What happens if there is a mutation in the regulatory gene?
Such a mutation – loss of an enhancer element – is called a regulatory mutation. It affects the spatial or temporal regulation of the gene without causing universal loss of the gene product.
What would happen if a mutation occurred in the operator region of the lac operon and a the repressor protein was unable to bind to it?
What would happen if the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator? In the presence of lactose, the lac operon will not be transcribed. In the absence of lactose, the lac operon will be transcribed.
What would happen if the operator sequence of the trp operon contained a mutation that prevented the repressor protein from binding to the operator?
What would happen if the operator sequence of the trp operon contained a mutation that prevented the repressor protein from binding to the operator? In the absence of tryptophan, the genes trpA-E will not be transcribed. In the absence of tryptophan, only genes trpE and trpD will be transcribed.
What would be the result of a mutation in the repressor protein that prevented it from binding lactose?
45. What would be the result of a mutation in the repressor protein that prevented it from binding lactose? The repressor will bind to lactose when it is removed from the operator. The repressor will bind the operator in the presence of lactose.
What happens if there is a mutation to the lacZ gene?
coli lac Z gene product, is defective or absent due to mutation. The phenotype of a cell that is lac Z is an inability to synthesize the lac Z gene product, ß-galactosidase. Without this enzyme, cells cannot metabolize lactose, and fail to grow if lactose is the only energy source.
Which of the following is the most likely result of a mutation in the lac operator that prevents release of the repressor protein?
Which of the following is the most likely result of a mutation in the lac repressor protein that prevents binding to the operator? The lactose permease protein will be produced, even in the absence of lactose.
What are regulatory mutations?
A change in DNA or RNA that alters the expression of other genes by a cell.
How does mutation result to change in the structure and function of a protein?
Sometimes, gene variants (also known as mutations) prevent one or more proteins from working properly. By changing a gene’s instructions for making a protein, a variant can cause a protein to malfunction or to not be produced at all.
What might be the effects of a mutation in the gene that codes for the lac repressor in E. coli?
The lac repressor might be unable to bind with the operator. As a result, RNA polymerase would not be prevented from beginning the process of transcription, and the lac genes would be turned on permanently. Another effect of the mutation might be that the lac repressor would be unable to bind with lactose.
What will happen if a mutation take place in I gene of lac operon such that it no longer can synthesise repressor protein?
LacZ gene encodes for β-galactosidase, lacY encodes for β-galactoside permease and lacA encodes for β-galactoside transacetylase. Hence if mutation occurs in the middle gene of the structural genes then permease will not be synthesized. Thus the correct answer is option B.
What is lacZ mutation?
lac Z- mutant: no functional protein (effectively no protein) Induced by lactose, but cannot grow on lactose.
What happens when lacY is mutated?
A mutant of Escherichia coli is described that grew on lactose only in the presence of isopropylthiogalactoside. This cell contained a defect in the lacY gene that resulted in the formation of a transport system with a poor affinity for lactose.