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.
Last Answer : (d) Operon - Structural genes, operator and promoter
Description : An important step in protein synthesis is transcription. Which of the following statement(s) is/are true concerning this process? a. The first step in gene transcription involves separating the double helix ... nucleus to the cytoplasm d. Only one protein can be produced from an initial mRNA strand
Last Answer : Answer: c Transcription of a gene begins at an initiation site associated with a specific DNA sequence, termed a promoter region. After binding to DNA, the RNA polymerase opens up a short ... different proteins from the same gene. mRNA is exported from the nucleus only after processing is complete
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 : In operon concept, regulator gene functions as (a) inhibitor (b) repressor (c) regulator (d) all of these.
Last Answer : a) inhibitor
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 : Operon model of gene regulation and organisation of prokaryotes was proposed by: (a) Messelson and Stahl (b) Wilkins and Franklin (c) Beadle and Tatum (d) Jacob and Monod
Last Answer : Ans. ((d))
Description : Induction of drug metabolizing enzymes involves: A. A conformational change in the enzyme protein to favour binding of substrate molecules B. Expression of enzyme molecules on the surface of ... C. Enhanced transport of substrate molecules into hepatocytes D. Increased synthesis of enzyme protein
Last Answer : D. Increased synthesis of enzyme protein
Description : A substance unrelated to substrate but capable of reversibly changing activity of enzyme by binding to a site other than active site is called (a) Competitive inhibitor (b) Non-competitive inhibitor (c) Catalytic inhibitor (d) Allosteric modulator/inhibitor
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 : 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 : .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 : 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 : That genes control heredity through their control on enzyme synthesis and that one gene controls the sythesis of one enzyme - the one gene one enzyme hypothesis — was proposed by (a) Beadle and Tatum (b) Darwin (c) Mendel (d) Morgan
Last Answer : Ans:(a)
Description : Chloramphenicol inhibits bacterial protein synthesis by: A. Binding to 30S ribosome and inhibiting attachment of aminoacyl tRNA B. Binding to 50S ribosome and preventing peptide bond formation C. Binding to ... chain D. Binding to both 30S and 50S ribosome and inducing misreading of mRNA code
Last Answer : B. Binding to 50S ribosome and preventing peptide bond formation
Description : Template/lock and key theory of enzyme action is supported by (A) Enzymes speed up reaction (B) Enzymes occur in living beings and speed up certain reactions (C) Enzymes determine the direction of reaction (D) Compounds similar to substrate inhibit enzyme activity
Last Answer : Answer : D
Description : If a coenzyme is required in an enzyme reaction, the former usually has the function of (A) Acting as an acceptor for one of the cleavage products of the substrate (B) Enhancing the specificity ... C) Increasing the number of receptor sites of the apo enzyme (D) Activating the substrate ENZYMES 167
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 : 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
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
Description : DNA mRNA C Proposed by Protein A B The figure gives an important concept in the genetic implication of DNA. Fill the blanks A, B and C. (a) A-Maurice Wilkins, B-Transcription, C-Translation ... c) A-Erwin Chargaff, B-Translation, C-Replication (d) A-Francis Crick, B-Translation, C-Transcription
Last Answer : (d) A-Francis Crick, B-Translation, C-Transcription
Description : The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A to C. DNA mRNA Proposed by Protein C A B (a) A - Transcription, B -Translation, C - Francis Crick (b) ... , B - Replication, C - James Watson (d) A - Translation, B - Transcription, C - Ervin Chargaff
Last Answer : (a) A - Transcription, B -Translation, C - Francis Crick
Description : A drug which prevents uric acid synthesis by inhibiting the enzyme Xanthine oxidase is (A) Aspirin (B) Allopurinal (C) Colchicine (D) Phenyl benzoate
Description : Methotrexate blocks the synthesis of thymidine monophosphate by inhibiting the activity of the enzyme: (A) Dihydrofolate reductase (B) Orotate phosphoribosyl transferase (C) Ribonucleotide reductase (D) Dihydroorotase
Description : A drug which prevents uric acid synthesis by inhibiting the enzyme xanthine oxidase is (A) Aspirin (B) Allopurinol (C) Colchicine (D) Probenecid
Last Answer : B
Description : The polyene antibiotics act by: A. Inhibiting fungal cytochrome P450 enzyme B. Binding to ergosterol and creating micropores in fungal cell membrane C. Inhibiting fungal DNA synthesis D. Disorienting microtubules in fungal cells
Last Answer : B. Binding to ergosterol and creating micropores in fungal cell membrane
Last Answer : (B) Allopurinol
Description : An enzyme promotes a chemical reaction by (A) Lowering the energy of activation (B) Causing the release of heat which acts as a primer (C) Increasing molecular motion (D) Changing the free energy difference between substrate and product
Description : The Michaehis-Menten hypothesis: (A) Postulates the formation of an enzyme substrate complex (B) Enables us to calculate the isoelectric point of an enzyme (C) States that the ... independent of substrate concentration (D) States that the reaction rate is proportional to substrate concentration
Description : Enzymes activity is controlled by (A) pH of the solution (B) Temperature (C) Concentration of the enzyme (D) Concentration of the substrate (E) All of these
Description : If all the enzymes, intermediates and cofactors of the citric acid cycle as well as an excess of the starting substrate acetylCoA are present and functional in an organelle free solution at the appropriate ... oxygen (B) Half life of enzyme (C) Turnover of intermediates (D) Reduction of cofactors
Description : Lineweaver – Burk double reciprocal plot is related to (A) Substrate concentration (B) Enzyme activity (C) Temperature (D) Both (A) and (B) ENZYMES 145
Description : The final step of gene expression is protein synthesis, which is also known as A- replication B- translation C- transcription D- none of these
Last Answer : translation
Description : The following is not a plant growth regulator a) Acetic acid b) Auxins c) Gibberellins d) Ethylene
Last Answer : a) Acetic acid
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 : Myosin bridges can be prevented from combining actin by two regulator proteins in resting muscle by (a) troponin (b) myofibril (c) troponin and tropomyosin (d) natural inhibiting proteins
Last Answer : Ans:(c)
Description : what enzyme is needed to catalyze synthesis of mRNA?
Last Answer : Helicase. It breaks the hydrogen bonds holding the complementary bases of DNA together (A with T, C with G). The separation of the two single strands of DNA creates a Y' shape called a replication fork ... , is the leading strand. The other oriented in the 5' to 3' direction is the lagging strand.
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 : The structural genes of lac operon transcribe mRNA which is a) polycistronic b) replicative c) monokaryotic d) monocistronic
Last Answer : a) polycistronic
Description : Which part of the brain controls respiration ?
Last Answer : The medullary part of the brain controls respiration.
Description : 7. In a recombinant DNA technology a plasmid vector must be cleaved by a) the same enzyme that leaves the donor gene b) modified DNA ligase c) a heated alkaline solution d) four separate enzymes
Last Answer : a) the same enzyme that leaves the donor gene
Description : During transcription, the DNA site at which RNA polymerase binds is called (a) promoter (b) regulator (c) receptor (d) enhancer.
Last Answer : d) enhancer
Last Answer : (a) promoter
Description : Pick out the wrong statement. (A) Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C ... in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & prod
Last Answer : (C) Enzymes help in increasing the activation energy of the reaction
Description : Why is the concept of a single gene as the ultimate unit of inheritance inadequate to provide a unitary explanation for protein synthesis, recombination, and mutation?
Last Answer : The primary function of the gene is to code for a protein product. Sufficient DNA must be present to account for each of the amino acids making up the primary structure of the protein. It is ... . The recon, the unit involved in recombination, may be only slightly shorter than the full cistron.
Description : Feedback term refers to (A) Effect of substrate on rate of enzymatic reaction (B) Effect of end product on rate reaction (C) Effect of enzyme concentration on rate of reaction (D) Effect of external compound on rate of reaction
Description : The rate of an enzyme catalyzed reaction was measured using several substrate concentrations that were much lower than Km, the dependence of reaction velocity on substrate concentration can best be ... constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration
Description : When [s] is equal to Km, which of the following conditions exist? (A) Half the enzyme molecules are bound to substrate (B) The velocity of the reaction is equal to Vmax (C) The velocity of the reaction is independent of substrate concentration (D) Enzyme is completely saturated with substrate