Gene regulation: lac operon
- The lactose present in the growth medium of bacteria is transported to the cell by the action of: Answer: 4. Permease Key idea: in the lac operon, permease carries lactose into the cell. The lac operon has three structural genes: z codes... 1
- Match List I with List II.List I: A. Gene 'a'; B. Gene 'y'; C. Gene 'i'; D. Gene 'z'List II: I. β-galactosidase; II. Transacetylase; III. Permease; IV. Repressor proteinChoose the correct answer from the options given below: Answer: 3. A-II, B-III, C-IV, D-I Key idea: In the lac operon, each gene codes for a specific protein. Gene i codes for the repressor protei... 1
- In an E.coli strain i gene gets mutated and its product can not bind the inducer molecule. If growth medium is provided with lactose, what will be the outcome ? Answer: 4. z, y, a genes will not be translated Key idea: If the repressor (product of the i gene) cannot bind the inducer, it stays bound t... 1
- Match the following genes of the Lac operon with their respective products :(a) i gene (i) β-galactosidase(b) z gene (ii) Permease(c) a gene (iii) Repressor(d) y gene (iv) TransacetylaseSelect the correct option. Answer: 3. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) Key idea: Lac operon: i gene codes for repressor; z for beta-galactosidase; y for permease... 1
- All of the following are part of an operon except Answer: 2. an enhancer Key idea: A prokaryotic operon has structural genes, a promoter and an operator (and a regulatory gene nearby). An en... 1
- Which of the following is required as inducer(s) for the expression of Lac operon ? Answer: 3. lactose Key idea: In the lac operon, lactose (as allolactose) is the inducer. It binds the repressor protein, which then leaves t... 1