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 : 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 : .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 : 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 : Which enzyme will be produced in a cell if there is a nonsense mutation in the lac Y gene? (a) Transacetylase (b) Lactose permease and transacetylase (c) β-galactosidase (d) Lactose permease
Last Answer : β-galactosidase
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 : 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 : 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)
Last Answer : d) (iii) (i) (iv) (ii)
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
Last Answer : Answer : B
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
Last Answer : Answer : A
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
Last Answer : Answer : C
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 : 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
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 : In E. coli, during lactose metabolism repressor binds to (a) regulator gene (b) operator gene (c) structural gene (d) promoter gen
Last Answer : (b) operator 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 : Lac operon is a cluster of genes present in (A) Human beings (B) E. coli (C) Lambda phage (D) All of these
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 : In the lac operon concept, a protein molecule is (A) Operator (B) Inducer (C) Promoter (D) Repressor
Description : acob and Monod studied lactose metabolism in E. coli and proposed operon concept. Operon concept is applicable for (a) all prokaryotes (b) all prokaryotes and some eukaryotes (c) all prokaryotes and all eukaryotes (d) all prokaryotes and some protozoans
Last Answer : (c) all prokaryotes and all eukaryotes
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 : 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
Description : Trancription of z, y and a genes of lac operon is prevented by (A) Lactose (B) Allo-lactose (C) Repressor (D) cAMP
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 : 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
Last Answer : Lactose
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
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
Description : Which one of the following is NOT part of an operon? a. Regulatory gene b. Operator c. Promoter d. Structural genes
Last Answer : d. Structural genes
Description : The ribosome binding site A- forms a stem-loop structure in the RNA B- is located upstream of the promoter sequence C- .is located immediately upstream of the start codon D- is more likely to be associated with an operon than with a gene encoding a single protein
Last Answer : .is located immediately upstream of the start codon
Description : The rivosome binding site A- forms a sltem- loop structure in the RNA B- is located upstream of the promoter sequence C- is located immediately upstream of the start codon D- is more likely to be associated with an operon than with a gene encoding a single protein
Last Answer : is located immediately upstream of the start codon
Description : 8. Non coding sequences present within a gene is called: (a) Exon (b) Operon (c) Promoter (d) Intron
Last Answer : (d) Intron
Description : To commence structural gene transcription the region which should be free on lac operation is (A) Promoter site (B) Operator locus (C) Y gene (D) A gene
Description : The enzyme deficient in Sandhoff’s disease is (A) α-Fucosidase (B) Hexosaminidase A and B (C) β-Galactosidase (D) β-Glucosidase
Description : The enzyme deficient in Krabbe’s disease is (A) Hexosaminidase A(B) Arylsuphatase A (C) β-Galactosidase (D) α-Fucosidase
Description : Farber’s disease is due to the deficiency of the enzyme: (A) α-Galactosidase (B) Ceramidase (C) β-Glucocerebrosidase (D) Arylsulphatase A.
Description : Krabbe’s disease is due to the deficiency of the enzyme: (A) Ceramide lactosidase (B) Ceramidase (C) β-Galactosidase (D) GM1 β-Galactosidase
Description : Gaucher’s disease is due to the deficiency of the enzyme: (A) α-Fucosidase (B) β-Galactosidase (C) β-Glucosidase (D) Sphingomyelinase
Description : The enzyme deficient in Fabry’s disease is (A) α-Galactosidase (B) β-Galactosidase (C) α-Glucosidase (D) β-Glucosidase
Description : β -Galactosidase is deficient in (A) Fabry’s disease (B) Krabbe’s disease (C) Gaucher’s disease (D) Metachromatic leukodystrophy
Description : Gaucher’s disease is due to deficiency of the enzyme: (A) Sphingomyelinase (B) Glucocerebrosidase (C) Galactocerbrosidase (D) β-Galactosidase
Description : A level of regulation, demonstrated by the termination of transcription if tryptophan is abundant, by the tryptophan operon in E.coli cells is called A.activation B.attenuation C.corepression D.desiccation
Last Answer : B.attenuation
Description : Why is the lac operon said to be an inducible operon? -Biology
Last Answer : answer: