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Lactose acts as an inducer in Lac operon by binding to the repressor protein, the repressor protein is produced by the inhibitory gene ( LacI) present upstream to the operon gene. The repressor protein binds to the operator (O) (a segment of DNA present on the gene present upstream of the operon), The repressor protein is produced continuously ...
Regulation Of Gene Expression. Protein synthesis begins at transcription, ends at translation and involves multiple steps. Therefore, regulation of gene expression can happen at any of these steps. In eukaryotes, gene regulation occurs at any of the following steps: Transcriptional level i.e. during the formation of the primary transcript.
Lac operon is made up of one regulator, one operator and three structural genes. The three structural genes are LacZ, LacY and LacA. LacZ encodes β-galactosidase (LacZ), an intracellular enzyme that cleaves the disaccharide lactose into glucose and galactose.
View Solution. Q 5. Explain role of inducer in lac operon with the help of diagram. What is switch on and off position in lac operon? View Solution. Click here:point_up_2:to get an answer to your question :writing_hand:draw a schematic laballed illustration of lac operon in a switched on state.
The lac operon has three structural genes. The lac Z gene codes for β -galactosidase which converts lactose into glucose and galactose. The lac Y gene codes for β -galactoside permease which transports lactose into the cell. The lac A gene codes for β -galactoside transacetylase. Thus, the correct answer is option A.
Regulator gene regulates the expression of structural genes by its protein products that are mostly transcription factors. These transcription factors/repressors bind to the operator region which is located just upstream the binding site of the RNA polymerase and hence prevent the binding and transcription. This makes option A incorrect and B ...
The lac operon is an operon responsible for transport and metabolism of lactose in Escherichia coli and other bacteria. Gene " i" is the r egulator gene that regulates the expression of structural genes by its protein product that are mostly transcription factors.
The lac operon is a negatively controlled inducible operon, where the inducer molecule is Lactose. If the inducer molecule is present, it binds to the repressor and changes its conformation so that it is unable to bind to the operator and thus gene expression is controlled.
I. Glucose binds to CAP binding site and activates the operon. II. In the absence of lactose, the repressor binds with the operator region. III. All three structural gene products are not essential for the metabolism of lactose. IV. The operator is a negative regulatory site bound by the lac repressor protein. View Solution.
Describe how the lac operon operates, both in the presence and absence of an inducer in E.coli. View Solution. Click here:point_up_2:to get an answer to your question :writing_hand:describe the lacoperon.
