Description : There are special proteins that help to open up DNA double helix in front of the replication fork. These proteins are (a) DNA ligase (b) DNA topoisomerase I (c) DNA gyrase (d) DNA polymerase I.
Last Answer : (c) DNA gyrase
Description : Negative supercoils are introduced in DNA by (A) Helicase (B) DNA ligase (C) DNA gyrase (D) DNA polymerase III holoenzyme
Last Answer : Answer : C
Description : During DNA replication, the strands separate by (a) DNA polymerase (b) topoisomerase (c) unwindase/helicase (d) gyrase.
Last Answer : b) topoisomerase
Description : Indicate the enzyme(s) inhibited by fluoroquinolones: A. Both 'A' and 'C' B. Topoisomerase II C. Topoisomerase IV D. DNA gyrase
Last Answer : D. DNA gyrase
Description : At a chromosome replication fork, the lagging strand consists of__ That is joined by___. a. RNA sequences; DNA ligase b. Okazaki Fragments; RNA Polymerase c. RNA sequences; ribosomes d. Okazaki fragments; DNA ligase
Last Answer : d. Okazaki fragments; DNA ligase
Description : Ciprofloxacin inhibits (A) DNA topisomerase II (B) DNA polymerase I (C) DNA polymerase III (D) DNA gyrase
Last Answer : Answer : D
Description : A consensus sequence on DNA, called TATA box, is the site for attachment of (A) RNA-dependent DNA polymerase (B) DNA-dependent RNA polymerase (C) DNA-dependent DNA polymerase (D) DNA topoisomerase II
Last Answer : Answer : B
Description : An eazyme produced by HIV that allows the integration of HIV DNA into the host cell's DNA is (1) Ligase (2) Integrase (3) Helicase (4) DNA gyrase
Last Answer : (2) Integrase Explanation: HIV's enzyme for inserting the DNA version of its genome into the host cell DNA is called its "integrase". HIV-1 integrase catalyzes the "cut-and-paste" action of ... to the clipped ends. It is also produced by viruses containing double-stranded DNAs for the same purpose.
Description : 1. Bacteria protect themselves from viruses by fragmenting viral DNA with a. Ligase b. Endonuclease c. Exonuclease d. Gyrase
Last Answer : Ans: Endonuclease.
Description : An eazyme produced by HIV that allows the integration of HIV DNA into the host cell’s DNA is : (1) Ligase (2) Integrase (3) Helicase (4) DNA gyrase
Last Answer : Integrase
Description : The region of DNA known as TATA BOX is the site for binding of (A) DNA polymerase (B) DNA topoisomerase (C) DNA dependent RNA polymerase (D) Polynucleotide phosphorylase
Description : Xeroderma pigmentosum results from a defect in (A) uvr ABC excinuclease (B) DNA polymerase I (C) DNA ligase (D) All of these
Last Answer : Answer : A
Description : Damage to DNA caused by ultraviolet radiation can be repaired by (A) uvr ABC excinuclease (B) DNA polymerase I (C) DNA ligase (D) All of these
Description : The α-amino group of the new amino acyl tRNA in the A site carries out a nucleophilic attack on the esterified carboxyl group of the peptidyl tRNA occupying the P site. This reaction is catalysed by (A) DNA polymerase (B) RNA polymerase (C) Peptidyl transferase (D) DNA ligase
Description : In DNA replication the enzyme required in the first step is (A) DNA directed polymerase (B) Unwinding proteins (C) DNA polymerase (D) DNA ligase
Description : The enzyme which catalyzes the unwinding of DNA helix during replication is: (1) Primase (2) Topoisomerase (3) Helicase (4) DNA polymerase
Last Answer : (3) Helicase Explanation: A type of helicase enzyme called DNA helicase catalyzes the unwinding of the DNA helix at the time of replication. It uses the energy released through hydrolysis of ATP ( ... The enzyme is needed to separate the two strands of DNA also during transcription and DNA repair.
Description : Which of the following enzymes are used to join bits of DNA? (a) Ligase (b) Primase (c) DNA polymerase (d) Endonuclease
Last Answer : a) Ligase
Description : The linking of antibiotic resistance gene with the plasmid vector became possible with (a) DNA polymerase (b) exonucleases (c) DNA ligase (d) endonucleases.
Last Answer : (c) DNA ligase
Description : Restriction endonucleases are enzymes which (a) make cuts at specific positions within the DNA molecule (b) recognize a specific nucleotide sequence for binding of DNA ligase (c) restrict the action of the enzyme DNA polymerase (d) remove nucleotides from the ends of the DNA molecule
Last Answer : (a) make cuts at specific positions within the DNA molecule
Description : A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using (a) EcoRI (b) Taq polymerase (c) polymerase III (d) ligase.
Last Answer : (d) ligase.
Description : Name the enzyme that facilitates opening of DNA helix during transcription. (a) DNA ligase (b) DNA helicase (c) DNA polymerase (d) RNA polymerase
Last Answer : b) DNA helicase
Description : A seals sticky ends of recombinant DNA segments. a. DNA Ligase b. restriction endonuclease c. protease d. RNA polymerase
Last Answer : b. restriction endonuclease
Description : Which of the following are examples of repair mechanisms in cells? a. mismatch repair b. excision repair c. DNA polymerase d. DNA ligase e. all are important in fixing mutations
Last Answer : e. all are important in fixing mutations
Description : The enzyme adds complementary bases to the DNA template strand during replication. a. Ligase b. Helicase c. DNA polymerase III d. RNA polymerase
Last Answer : d. RNA polymerase
Description : Which of the following molecule catalyzes the transpeptidation reaction? A.RNA polymerase B.Peptidyl transferase C.DNA ligase D.DNA polymerase
Last Answer : B.Peptidyl transferase
Description : Which of the following molecule catalyzes the transpeptidation reaction? A- RNA Polymerase B- Peptidlytransferase C- DNA ligase D- DNA polymerase
Last Answer : Peptidlytransferase
Description : Which of the following molecule catalyzes the transpeptidation reaction? A- RNA polymerase B- .Peptidyltransferase C- DNA ligase D- .DNA polymerase
Last Answer : .Peptidyltransferase
Description : DNA fragments generated by the restriction endo- nucleases in a chemical reaction can be separated by (a) electrophoresis (b) restriction mapping (c) centrifugation (d) polymerase chain reaction.
Last Answer : (a) electrophoresis
Description : From a DNA-RNA hybrid, DNA can be obtained by addition of (A) DNA B protein and ATP (B) Helicase and ATP (C) DNA topoisomerase I (D) Alkali
Description : DNA topoisomerase I of E. coli catalyses (A) Relaxation of negatively supercoiled DNA (B) Relaxation of positively supercoiled DNA (C) Conversion of negatively supercoiled DNA into positively supercoiled DNA (D) Conversion of double helix into supercoiled DNA
Description : Vinca alkaloids exert antitumor activity by: A. Activating topoisomerase II to cause breaks in DNA strands B. Crosslinking DNA strands C. Inhibiting DNA mediated RNA synthesis D. Inhibiting polymerization of tubulin to form intracellular microtubules
Last Answer : D. Inhibiting polymerization of tubulin to form intracellular microtubules
Description : Which of the following reunites the exon segments after RNA splicing? (a) RNA polymerase (b) RNA primase (c) RNA ligase (d) RNA proteose
Last Answer : a) RNA polymerase
Description : Which of the following reunites the exon segments after RNA splicing? (a) RNA polymerase (b) RNA primase (c) RNA ligase (d) RNA proteoses
Last Answer : (c) RNA ligase
Description : One of the first enzymes synthesized by many bacteriophage is __________ , an RNA dependent RNA polymerase A.RNA transcriptase B.RNA polymerase C.RNA ligase D.RNA replicase
Last Answer : D.RNA replicase
Description : Viropexis takes place in the phagocytic vacuoles and is due to the action of Enzymes A- DNA gyrase B- lysosomal protease C- lysosomal lipase D- all of these
Last Answer : lysosomal protease
Description : α-Amanitin inhibits (A) DNA polymerase II of prokaryotes (B) DNA polymerase α of eukaryotes (C) RNA polymerase II of eukaryotes (D) RNA-dependent DNA polymerase
Description : Primase activity is present in (A) DNA polymerase II (B) DNA polymerase α (C) DNA polymerase β (D) DNA polymerase δ
Description : A mammalian DNA polymerase among the following is (A) DNA polymerase α (B) DNA polymerase I (C) DNA polymerase II (D) DNA polymerase IV
Description : Reverse transcriptase activity is present in the eukaryotic: (A) DNA polymerase α (B) DNA polymerase γ (C) Telomerase (D) DNA polymerase II
Description : Ribonucleotides of RNA primer are replaced by deoxyribonucleotides by the enzyme: (A) DNA polymerase I (B) DNA polymerase II (C) DNA polymerase III holoenzyme (D) All of these
Description : Deoxyribonucleotides are added to RNA primer by (A) DNA polymerase I (B) DNA polymerase II (C) DNA polymerase III holoenzyme (D) All of these
Description : In the biosynthesis of c-DNA, the joining enzyme ligase requires (A) GTP (B) ATP (C) CTP (D) UTP
Description : DNA ligase of E. coli requires which of the following co-factors? (A) FAD (B) NAD+ (C) NADP+ (D) NADH
Description : The enzyme DNA ligase (A) Introduces superhelical twists (B) Connects the end of two DNA chains (C) Unwinds the double helix (D) Synthesises RNA primers
Description : Choose the correct statement about topotecan: A. It is a DNA topoisomerase I inhibitor which causes single strand DNA breaks B. It is a cell cycle specific anticancer drug C. It is a COMT-inhibitor used in advanced parkinsonism D. Both 'A' and 'B' are correc
Last Answer : D. Both 'A' and 'B' are correct
Description : The enzyme which catalyzes the unwinding of DNA helix during replication is: (1) Primase (2) Topoisomerase (3) Helicase (4) DNApolymerase
Last Answer : C option is the answer
Description : The normal function of restriction endonucleases is to (A) Excise introns from hrRNA (B) Polymerize nucleotides to form RNA (C) Remove primer from okazaki fragments (D) Protect bacteria from foreign DNA
Description : Okasaki fragments are small bits of (A) RNA (B) DNA (C) DNA with RNA heads (D) RNA with DNA heads