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

1 Answer

Answer :

Answer :  C

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Description : A group of genes whose activity is coordinated by a DNA site is – (1) operon (2) cistron (3) polysome (4) polypeptide

Last Answer : (1) operon Explanation: The operon is defined as a group of genes whose activity is coordinated by a DNA site. An operon is a functioning unit of genomic DNA containing a cluster ... together in the cytoplasm, or undergo trans-splicing to create monocistronic mR-NAs that are translated separately.

Description : A group of genes whose activity is coordinated by a DNA site is called: (1) operon (2) cistron (3) polysome (4) polypeptide

Last Answer : operon

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 : Cistron is a) The coding sequence of DNA b) The functional unit of DNA molecule that codes for a particular gene product c) Intervening non coding sequence of DNA d) The sequences which are removed during RNA splicing.

Last Answer : b) The functional unit of DNA molecule that codes for a particular gene product c) Intervening non coding sequence of DNA

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.

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

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

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

Description : The equivalent of a structural gene is (a) muton (b) cistron (c) operon (d) recon.

Last Answer : (a) muton

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

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

Last Answer : a) inhibitor

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 : 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 : 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)

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 : 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

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

Last Answer : Answer : B

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 : 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

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

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

Last Answer : Answer : D

Description : 8. Non coding sequences present within a gene is called: (a) Exon (b) Operon (c) Promoter (d) Intron

Last Answer : (d) Intron

Description : Unit of genetic information: (A) DNA (B) RNA (C) Cistron (D) None of these

Last Answer : Answer : C

Description : Tetracylin prevents synthesis of polypeptide by (A) Blocking mRNA formation from DNA (B) Releasing peptides from mRNA-tRNA complex (C) Competing with mRNA for ribosomal binding sites (D) Preventing binding of aminoacyl tRNA

Last Answer : Answer : D

Description : Regulator gene controls chemical synthesis (Operon concept) by (a) Inhibiting transcription of mRNA (b) Inhibiting enzymes (c) Inhibiting passage of mRNA (d) Inhibiting substrate enzyme reaction

Last Answer : Ans. ((a))

Description : A gene that takes part in synthesis of polypeptide is

Last Answer : A gene that takes part in synthesis of polypeptide is A. Structural gene B. Regulator gene C. Operator gene D. Leading strand

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 : .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 : Negative regulation of protein synthesis is accomplished by A- allosteric inhibition B- the binding of RNA polymerase to the promoter C- the binding of a repressor to the DNA D- the binding of a repressor to the RNA polymerase

Last Answer : the binding of a repressor to the DNA

Description : Genetic information originates from (A) Cistron of DNA (B) Codons of mRNA (C) Anticodons of tRNA (D) Histones of nucleoproteins

Last Answer : Answer : A

Description : What is the relation between gene, cistron, muton and recon? -Biology

Last Answer : answer:

Description : Gene and cistron words are sometimes used synonymously because (a) one cistron contains many genes (b) one gene contains many cistrons (c) one gene contains one cistron (d) one gene contains no cistron

Last Answer : (b) one gene contains many cistrons

Description : Gene and cistron words are sometimes used synonymously because (a) one cistron contains many genes (b) one gene contains many cistrons (c) one gene contains one cistron (d) one gene contains no cistron.

Last Answer : c) one gene contains one cistron

Description : The ‘rho’ (ρ) factor is involved (A) To increase the rate of RNA synthesis (B) In binding catabolite repressor to the promoter region (C) In proper termination of transcription (D) To allow proper initiation of transcriptide

Last Answer : Answer : C

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 : 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 : 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 : 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 : 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

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

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

Last Answer : Answer : A

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

Description : Nonsense codons bring about (A) Amino acid activation (B) Initiation of protein synthesis (C) Termination of protein synthesis (D) Elongation of polypeptide chains

Last Answer : Answer : C

Description : Streptomycin prevents synthesis of polypeptide by (A) Inhibiting initiation process (B) Releasing premature polypeptide (C) Inhibiting peptidyl transferase activity (D) Inhibiting translocation

Last Answer : Answer : A

Description : The amino terminal of all polypeptide chain at the time of synthesis in E. coli is tagged to the amino acid residue: (A) Methionine (B) Serine (C) N-formyl methinine(D) N-formal serine

Last Answer : Answer : C

Description : What are large randomly repeating non-coding DNA stretches called as? a. Satellite DNA b. Micro arrays c. Gene d. Allele

Last Answer : a. Satellite DNA

Description : DNA present in a structural gene that does not seem to have a specific coding function is known as what?

Last Answer : ANSWER: INTRON

Description : Where is the trp repressor gene located? -Biology

Last Answer : answer: