Repressible operon system is usually found in (i)____ pathways. The pathway's end product serves as a (ii) ______ to activate the repressor, turn off enzyme synthesis and prevent overproduction of the end product of the pathway. Genes for this operon are usually switched (iii)_____ and the repressor is synthesised in an (iV)_____ .

Inducible operon system usually accurs in (i) ___ pathways. Nutrient moleculses serve as (ii) ______ to stimulate production of the enzymes necessary for their breakdown. Genes for inducible operon are usually switched (iii)_____ and the repressor is synthesised in an (iv)____ form.

The lac operon consists of a regulation gene and three structural gene. The lactose acts as inducer. In the presence of an Inducer such as lactose, the repressor is in inactivated during the interaction. This allows RNA polymerase access to the promoter and transcription proceeds. The repressor is synthesized which in turn binds with the operator region of the operon and prevents RNA polymerase from transcribing the operon. Which of the following statement is true in reference to the lac operon process in E.coli? (i) Galactosidase is the only enzyme produced in large quantities when lac operon is turned on (ii) The messenger RNA in lac operon is a polycistronic mRNA

Go though the following statements (i) Meselson & stahl used cesium chloride density gradient to distinguish heavy DNA molecules from the normal DNA molecules. (ii) In meselson & Stahl experiment the DNA that was extracted from the culture one generation after the transfer from .^(15)N to .^(14)N , was composed of equal amount of hybrid (intermediate) DNA and of light DNA. (iii) In prokaryotes, control f the rate of transcriptional initiation is the predominant site for control of gene expression. (iv) In lac operon, the repressor is synthesised only at the time when the level of metabolite is in excess. Find out the correct statements?

Go though the following statements (i) Meselson & stahl used cesium chloride density gradient to distinguish heavy DNA molecules from the normal DNA molecules. (ii) In meselson & Stahl experiment the DNA that was extracted from the culture one generation after the transfer from .^(15)N to .^(14)N , was composed of equal amount of hybrid (intermediate) DNA and of light DNA. (iii) In prokaryotes, control the rate of transcriptional initiation is the predominant site for control of gene expression. (iv) In lac operon, the repressor is synthesised only at the time when the level of metabolite is in excess. Find out the correct statements?

Go though the following statements (i) Meselson & stahl used cesium chloride density gradient to distinguish heavy DNA molecules from the normal DNA molecules. (ii) In meselson & Stahl experiment the DNA that was extracted from the culture one generation after the transfer from .^(15)N to .^(14)N , was composed of equal amount of hybrid (intermediate) DNA and of light DNA. (iii) In prokaryotes, control f the rate of transcriptional initiation is the predominant site for control of gene expression. (iv) In lac operon, the repressor is synthesised only at the time when the level of metabolite is in excess. Find out the correct statements?

Go though the following statements (i) Meselson & stahl used cesium chloride density gradient to distinguish heavy DNA molecules from the normal DNA molecules. (ii) In meselson & Stahl experiment the DNA that was extracted from the culture one generation after the transfer from .^(15)N to .^(14)N , was composed of equal amount of hybrid (intermediate) DNA and of light DNA. (iii) In prokaryotes, control f the rate of transcriptional initiation is the predominant site for control of gene expression. (iv) In lac operon, the repressor is synthesised only at the time when the level of metabolite is in excess. Find out the correct statements?

Match the following genes of the lac operon with their respective products: (a) (i) gene (i) beta- galactosidase (b) (z) gene (ii) permease (c) (a) gene (iii) repressor (d) (y) gene (iv) transacetylase