.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.

.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.
by

1 Answer

Answer :

(b) they cannot synthesise functional beta galactosidase
by

Related questions

.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.

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

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.

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Last Answer : (a) The lac operon is induced

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

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Last Answer : (c) β-galactosidase

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

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Last Answer : Gene – A gets transcribed into mRNA which produces β-galactoside permease b) Inducer-Repressor complex is formed

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)

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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

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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)

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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)

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

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

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Last Answer : β-galactosidase

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

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Last Answer : Answer : B

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

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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

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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

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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

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

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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

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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

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Last Answer : b) lactose is available to the cell

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

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Last Answer : Answer : B

In E coli Lac operon gets switched on when:

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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

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Last Answer : Answer : D

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

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Last Answer : Answer : B

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

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Last Answer : Answer : D

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

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Last Answer : Answer : A

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

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In lac operon, lactose acts are

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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

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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

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The colonies of recombinant bacteria appear white in contrast to blue colonies of non-recombinant bacteria because of (a) insertional inactivation of alpha galactosidase in recombinant bacteria (b) inactivation of glycosidase enzyme in recombinant bacteria (c) non-recombinant bacteria containing beta galactosidase (d) insertional inactivation of alpha galactosidase in non-recombinant bacteria.

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Last Answer : (c) non-recombinant bacteria containing beta galactosidase

In many types of cancer, proteins that are crucial regulators of the cell cycle are often mutated and cannot function correctly. This leads to the evasion of apoptosis and to the loss of control of cell proliferation? For example, many cancer cells carry two mutant copies of the gene that codes for a tumor suppressor protein named p53. What is the normal function of p53 that is lost when it is mutated?

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Last Answer : (b) one regulatory gene and three structural genes

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Last Answer : Answer : A

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

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Last Answer : Answer : C

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Last Answer : Answer : D

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In E. coli, during lactose metabolism repressor binds to (a) regulator gene (b) operator gene (c) structural gene (d) promoter gen

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If a woman developed skin cancer as result of a mutated gene in the skin cells of her arms could she pass skin cancer gene to her children justify your answer?

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Last Answer : Need answer

Metronidazole is selectively active against anaerobic organisms because: A. Aerobes have an active transport mechanism to pump it out of their cell B. Only anaerobes reduce it to generate the reactive nitro radical C. It is rapidly inactivated in the presence of oxygen D. It binds to DNA of anaerobes with high affinity

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Consider the following statements: 1. Normal diet should contain 75gm of fat. 2. Fatty acids should be a part of human diet. 3. The cells of the human body cannot synthesise any fatty acids. 4. Deficiency diseases develop due to the absence of unsaturated fatty acids called essential fatty acids. Which of the above statements are correct? (a) 1, 2 (b) 2, 3 (c) 1, 2, 3, 4 (d) 1, 2, 4

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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

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In Lac-operon, repressor protein binds to

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

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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

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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

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.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. (

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