In the ’lac operon’ concept, which of the following is a protein? (A) Operator (B) Repressor (C) Inducer (D) Vector

In the ’lac operon’ concept, which of the following is a protein? (A) Operator (B) Repressor (C) Inducer (D) Vector
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Answer :  B
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In the lac operon concept, a protein molecule is (A) Operator (B) Inducer (C) Promoter (D) Repressor

Description : In the lac operon concept, a protein molecule is (A) Operator (B) Inducer (C) Promoter (D) Repressor

Last Answer : Answer : D

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) Inducer-Repressor complex is formed c) Lactose inactivates repressor protein d) RNA polymerase transcribe Z-gene, Y-gene and A-gene e) Allolactose is the inducer of lac operon

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

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) Attaching to promoter region and facilitating the binding of RNA polymerase holoenzyme (D) Binding to repressor subunits so that the repressor cannot attach to the operator locus

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

.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. (

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

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 : 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

Last Answer : Answer : B

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 inactivated by an inducer (C) Only after an inducer protein, which can be inactivated by a corepressor, switches it on (D) Only after an inducer protein, which is activated by an inducer, switch it on

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

Last Answer : Answer : D

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 : 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

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 operator region. (iii)The z-gene codes for permease. (iv) This was elucidated by Francois Jacob and Jacques Monod. The correct statements are (a) (ii) and (iii) (b) (i) and (iii) (c) (ii) and (iv) (d) (i) and (ii)

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)

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 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

Last Answer : Answer : D

In Lac-operon, repressor protein binds to

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

.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 because excess of β-galactosidase can switch off transcription (c) positive and inducible because it can be induced by lactose (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.

Last Answer : (d) negative and inducible because repressor protein prevents transcription.

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 because excess of β-galactosidase can switch off transcription (c) positive and inducible because it can be induced by lactose (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.

Last Answer : (d) negative and inducible because repressor protein prevents transcription.

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 : 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

Trancription of z, y and a genes of lac operon is prevented by (A) Lactose (B) Allo-lactose (C) Repressor (D) cAMP

Description : Trancription of z, y and a genes of lac operon is prevented by (A) Lactose (B) Allo-lactose (C) Repressor (D) cAMP

Last Answer : Answer : C

Which one of the following is wrongly matched? (a) Transcription - Writing information from DNA to tRNA. (b) Translation - Using information in mRNA to make protein. (c) Repressor protein - Binds to operator to stop enzyme synthesis. (d) Operon - Structural genes, operator and promoter.

Description : Which one of the following is wrongly matched? (a) Transcription - Writing information from DNA to tRNA. (b) Translation - Using information in mRNA to make protein. (c) Repressor protein - Binds to operator to stop enzyme synthesis. (d) Operon - Structural genes, operator and promoter.

Last Answer : (c) Repressor protein - Binds to operator to stop enzyme synthesis.

Which one of the following is wrongly matched? (a) Transcription - Writing information from DNA to tRNA. (b) Translation - Using information in mRNA to make protein. (c) Repressor protein - Binds to operator to stop enzyme synthesis. (d) Operon - Structural genes, operator and promoter.

Description : Which one of the following is wrongly matched? (a) Transcription - Writing information from DNA to tRNA. (b) Translation - Using information in mRNA to make protein. (c) Repressor protein - Binds to operator to stop enzyme synthesis. (d) Operon - Structural genes, operator and promoter.

Last Answer : (d) Operon - Structural genes, operator and promoter

When does the lac repressor protein bind to the operator? -Biology

Description : When does the lac repressor protein bind to the operator? -Biology

Last Answer : answer:

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

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

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

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 : Lactose

The minimum effective size of an operator for lac repressor binding is (A) 5 base pairs (B) 10 base pairs (C) 15 base pairs (D) 17 base pairs

Description : The minimum effective size of an operator for lac repressor binding is (A) 5 base pairs (B) 10 base pairs (C) 15 base pairs (D) 17 base pairs

Last Answer : Answer : D

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) (D) (a) (iii) (iv) (i) (ii) (b) (i) (iii) (ii) (iv) (c) (iii) (i) (ii) (iv) (d) (iii) (i) (iv) (ii)

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)

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) (D) (a) (iii) (iv) (i) (ii) (b) (i) (iii) (ii) (iv) (c) (iii) (i) (ii) (iv) (d) (iii) (i) (iv) (ii)

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 : d) (iii) (i) (iv) (ii)

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 : 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

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 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

Last Answer : Answer : D

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 : 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

Last Answer : Answer : D

RNA polymerase holoenzyme binds to lac operon at the following site: (A) i gene (B) z gene (C) Operator locus (D) Promoter region

Description : RNA polymerase holoenzyme binds to lac operon at the following site: (A) i gene (B) z gene (C) Operator locus (D) Promoter region

Last Answer : Answer : D

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 (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

Last Answer : Answer : D

The function of a repressor protein in an operon system is to prevent synthesis by binding to (A) The ribosome (B) A specific region of the operon preventing transcription of structural genes (C) The RNA polymerase (D) A specific region of the mRNA preventing translation to protein

Description : The function of a repressor protein in an operon system is to prevent synthesis by binding to (A) The ribosome (B) A specific region of the operon preventing transcription of structural genes (C) The RNA polymerase (D) A specific region of the mRNA preventing translation to protein

Last Answer : Answer : B

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 : 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

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 : 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

In operon concept, regulator gene functions as (a) inhibitor (b) repressor (c) regulator (d) all of these.

Description : In operon concept, regulator gene functions as (a) inhibitor (b) repressor (c) regulator (d) all of these.

Last Answer : a) inhibitor

Which one of the following binds to specific nucleotide sequences that are upstream and most distant from the start site? (A) RNA polymerase (B) Repressor (C) Inducer (D) Restriction

Description : Which one of the following binds to specific nucleotide sequences that are upstream and most distant from the start site? (A) RNA polymerase (B) Repressor (C) Inducer (D) Restriction

Last Answer : Answer : A

Which one of the following binds to specific nucleotide sequences? (A) RNA polymerase (B) Repressor (C) Inducer (D) Restriction

Description : Which one of the following binds to specific nucleotide sequences? (A) RNA polymerase (B) Repressor (C) Inducer (D) Restriction

Last Answer : Answer : A

The smallest unit of DNA capable of coding for the synthesis of a polypeptide is (A) Operon (B) Repressor gene (C) Cistron (D) Replicon

Description : The smallest unit of DNA capable of coding for the synthesis of a polypeptide is (A) Operon (B) Repressor gene (C) Cistron (D) Replicon

Last Answer : Answer : C

Lac operon is a cluster of genes present in (A) Human beings (B) E. coli (C) Lambda phage (D) All of these

Description : Lac operon is a cluster of genes present in (A) Human beings (B) E. coli (C) Lambda phage (D) All of these

Last Answer : Answer : B

The gene of lac operon which has constitutive expression is (A) i (B) c (C) z (D) p

Description : The gene of lac operon which has constitutive expression is (A) i (B) c (C) z (D) p

Last Answer : Answer : A

.An environmental agent, which triggers transcription from an operon, is a (a) depressor (b) controlling element (c) regulator (d) inducer.

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.

Repressor binds to DNA sequence and regulate the transcription. This sequence is called (A) Attenuator (B) Terminator (C) Anti terminator (D) Operator

Description : Repressor binds to DNA sequence and regulate the transcription. This sequence is called (A) Attenuator (B) Terminator (C) Anti terminator (D) Operator

Last Answer : Answer : D

Difference between lac repressor and trp repressor. -Biology

Description : Difference between lac repressor and trp repressor. -Biology

Last Answer : answer:

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 : 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

Last Answer : Answer : B

Why is the lac operon said to be an inducible operon? -Biology

Description : Why is the lac operon said to be an inducible operon? -Biology

Last Answer : answer:

What does the lac operon in bacteria code for? -Biology

Description : What does the lac operon in bacteria code for? -Biology

Last Answer : answer:

What genes are parts of the lac operon? -Biology

Description : What genes are parts of the lac operon? -Biology

Last Answer : answer:

In lac operon, lactose acts are

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

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

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

Lac operon’ in E. coli, is induced by (a) ‘I’ gene (b) promoter gene (c) β-galactosidase (d) lactose.

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

The lac operon is an example of (a) repressible operon (b) overlapping genes (c) arabinose operon (d) inducible operon.

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.

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 induced. (b) E.coli cells stop dividing. (c) The lac operon is repressed. (d) All operons are induced.

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

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

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

.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 (b) they cannot synthesise functional beta galactosidase (c) in the presence of glucose, E.coli cells do not utilise lactose (d) they cannot transport lactose from the medium into the cell.

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