Description : Which of the following is required as inducer(s) for the expression of Lac operon? (a) Lactose (b) Lactose and galactose (c) Glucose (d) Galactose
Last Answer : (c) Glucose
Description : Select the two correct statements out of the four (i - iv) statements given below about lac operon. (i) Glucose or galactose may bind with the repressor and inactivate it. (ii) In the absence of lactose, the repressor binds with the ... (iii) (b) (i) and (iii) (c) (ii) and (iv) (d) (i) and (ii)
Last Answer : (c) (ii) and (iv)
Description : The enzymes encoded by z, y and a genes of lac operon are inducible, and their inducer is (A) Lactose (B) Allo-lactose (C) Catabolite gene activator protein (D) All of these
Last Answer : Answer : B
Description : Select the incorrect statement out of the five given below about lac operon when Lactose is present in the medium. a) Gene - A gets transcribed into mRNA which produces β-galactoside permease b) ... polymerase transcribe Z-gene, Y-gene and A-gene e) Allolactose is the inducer of lac operon
Last Answer : Gene – A gets transcribed into mRNA which produces β-galactoside permease b) Inducer-Repressor complex is formed
Description : Expression of structural genes of lac operon is affected by all the following except (A) Lactose or its analogues (B) Repressor tetramer (C) cAMP (D) CAP-cAMP complex
Last Answer : Answer : C
Description : Lactose or its analogues act as positive regulators of lac operon by (A) Attaching to i gene and preventing its expression (B) Increasing the synthesis of catabolite gene activator protein (C) ... holoenzyme (D) Binding to repressor subunits so that the repressor cannot attach to the operator locus
Last Answer : Answer : D
Description : The wild type E.coli cells are growing in normal medium with glucose. They are transferred to a medium containing only lactose as sugar. Which of the following changes take place? (a) The lac operon is ... ) E.coli cells stop dividing. (c) The lac operon is repressed. (d) All operons are induced.
Last Answer : (a) The lac operon is induced
Description : .E.coli cells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because (a) the lac operon is constitutively active in these cells ( ... coli cells do not utilise lactose (d) they cannot transport lactose from the medium into the cell.
Last Answer : (b) they cannot synthesise functional beta galactosidase
Description : In the ’lac operon’ concept, which of the following is a protein? (A) Operator (B) Repressor (C) Inducer (D) Vector
Description : In the lac operon concept, a protein molecule is (A) Operator (B) Inducer (C) Promoter (D) Repressor
Description : .In negative operon, (a) co-repressor binds with repressor (b) co-repressor does not bind with repressor (c) co-repressor binds with inducer (d) cAMP have negative effect on lac operon. (
Last Answer : co-repressor binds with repressor
Description : In lac operon, lactose acts are
Last Answer : In lac operon, lactose acts are A. Inducer B. Co-inducer C. Repressor D. Co-repressor
Description : Trancription of z, y and a genes of lac operon is prevented by (A) Lactose (B) Allo-lactose (C) Repressor (D) cAMP
Description : .Gene regulation governing lactose operon of E.coli that involves the lac I gene product is (a) negative and repressible because repressor protein prevents transcription (b) feedback inhibition ... be induced by lactose (d) negative and inducible because repressor protein prevents transcription.
Last Answer : (d) negative and inducible because repressor protein prevents transcription.
Description : Lac operon’ in E. coli, is induced by (a) ‘I’ gene (b) promoter gene (c) β-galactosidase (d) lactose.
Last Answer : (c) β-galactosidase
Description : What does “lac” refer to in what we call the lac operon? (a) Lactose (b) Lactase (c) Lac insect (d) The number 1,00,000
Last Answer : (a) Lactose
Description : Gene regulation governing lactose operon of E.coli that involves the lac I gene product is (a) negative and repressible because repressor protein prevents transcription (b) feedback inhibition ... be induced by lactose (d) negative and inducible because repressor protein prevents transcription.
Description : 5. Lac operon transcribed when a) lactose is needed by the cell b) lactose is available to the cell c) lactic acid is needed by the cell d) lactic acid is available to the cell
Last Answer : b) lactose is available to the cell
Description : The regulatory i gene of lac operon (A) Is inhibited by lacotse (B) Is inhibited by its own product, the repressor protein (C) Forms a regulatory protein which increases the expression of downstream structural genes (D) Is constitutively expressed
Description : The gene of lac operon which has constitutive expression is (A) i (B) c (C) z (D) p
Last Answer : Answer : A
Description : Which of the following reaction gives lactose? (A) UDP galactose and glucose (B) UDP glucose and galactose (C) Glucose and Galactose (D) Glucose, Galactose and UTP
Last Answer : A
Description : Which of the following is an epimeric pair? (A) Glucose and fructose (B) Glucose and galactose (C) Galactose and mannose (D) Lactose and maltose
Last Answer : B
Description : A carbohydrate found only in milk is (A) Glucose (B) Galactose (C) Lactose (D) Maltose
Last Answer : C
Description : The sugar found in milk is (A) Galactose (B) Glucose (C) Fructose (D) Lactose
Last Answer : D
Description : Lactose is composed of (a) glucose + galactose (b) fructose + galactose (c) glucose + fructose (d) glucose + glucose.
Last Answer : (a) glucose + galactose
Description : Positive control of induction is best described as a control system in which an operon functions (A) Unless it is switched off by a derepressed repressor protein (B) Only after a repressor protein is ... on (D) Only after an inducer protein, which is activated by an inducer, switch it on
Description : .An environmental agent, which triggers transcription from an operon, is a (a) depressor (b) controlling element (c) regulator (d) inducer.
Last Answer : (d) inducer.
Description : Why is the lac operon said to be an inducible operon? -Biology
Last Answer : answer:
Description : What does the lac operon in bacteria code for? -Biology
Description : What genes are parts of the lac operon? -Biology
Description : In Lac-operon, repressor protein binds to
Last Answer : In Lac-operon, repressor protein binds to A. Regulator gene B. Operator gene C. Promoter gene D. Structural gene
Description : The region of the Lac operon which must be free from structural gene transcription to occur is (A) The operator locus (B) The promoter site (C) The ‘a’ gene (D) The ‘i’ gene
Description : Which of the following genes of the E.coli “Lac operon” codes for a constitutive protein? (A) The ‘a’ gene (B) The ‘i’ gene (C) The ‘c’ gene (D) The ‘z’ gene
Description : Lac operon of E. coli contains _______ is continuity. (A) Regulator and operator genes only (B) Operator and structural genes only (C) Regular and structural genes only (D) Regulator, operator and structural genes
Description : The coding sequences in lac operon include (A) i gene (B) i gene, operator locus and promoter (C) z, y and a genes (D) i, z, y and a genes
Description : Binding of RNA polymerase holoenzyme to the promoter region of lac operon is facilitated by (A) Catabolite gene activator protein (CAP) (B) cAMP (C) CAP-cAMP complex (D) None of these
Description : Transcription of structural genes of lac operon is prevented by binding of the repressor tetramer to (A) i gene (B) Operator locus (C) Promoter (D) z gene
Description : RNA polymerase holoenzyme binds to lac operon at the following site: (A) i gene (B) z gene (C) Operator locus (D) Promoter region
Description : Lac operon is a cluster of (A) Three structural genes (B) Three structural genes and their promoter (C) A regulatory gene, an operator and a promoter (D) A regulatory gene, an operator, a promoter and three structural genes
Description : Lac operon is a cluster of genes present in (A) Human beings (B) E. coli (C) Lambda phage (D) All of these
Description : Select the correct match. (a) Alec Jeffreys - Streptococcus pneumoniae (b) Alfred Hershey and - TMV Martha Chase (c) Matthew Meselson - Pisum sativum and F. Stahl (d) Francois Jacob and - Lac operon Jacques Monod
Last Answer : (a) Alec Jeffreys - Streptococcus pneumoniae
Description : Match the following genes of the Lac operon with their respective products. (A) i gene (i) b-galactosidase (B) z gene (ii) Permease (C) a gene (iii)Repressor (D) y gene (iv) Transacetylase Select the correct option. (A) (B) (C) ( ... ) (iii) (ii) (iv) (c) (iii) (i) (ii) (iv) (d) (iii) (i) (iv) (ii)
Last Answer : (a) (iii) (iv) (i) (ii)
Description : The lac operon is an example of (a) repressible operon (b) overlapping genes (c) arabinose operon (d) inducible operon.
Last Answer : (d) inducible operon.
Description : .The lac operon consists of (a) four regulatory genes only (b) one regulatory gene and three structural genes (c) two regulatory genes and two structural genes (d) three regulatory genes and three structural genes.
Last Answer : (b) one regulatory gene and three structural genes
Last Answer : (d) Francois Jacob and - Lac operon Jacques Monod
Last Answer : d) (iii) (i) (iv) (ii)
Description : An example of an inducible group of genes is the ______. a. ARG operon b. NAC operon c. LAC operon d. SAC operon
Last Answer : c. LAC operon
Description : The structural genes of lac operon transcribe mRNA which is a) polycistronic b) replicative c) monokaryotic d) monocistronic
Last Answer : a) polycistronic
Description : 5. In E coli Lac operon gets switched on when: a) Lactose is present and binds to the repressor b) Repressor binds to the operator c) RNA polymerase binds to the operator d) Lactose is present and binds to the RNA polymerase
Last Answer : a) Lactose is present and binds to the repressor
Description : Select the correct match : (1) Alec Jeffreys – Streptococcus pneumoniae (2) Alfred Hershey and – TMV Martha Chase (3) Matthew Meselson – Pisum sativum and F. Stahl (4) Francois Jacob and – Lac operon Jacques Monod
Last Answer : (4) Francois Jacob and – Lac operon Jacques Monod