Negative supercoils are introduced in DNA by (A) Helicase (B) DNA ligase (C) DNA gyrase (D) DNA polymerase III holoenzyme

1 Answer

Answer :

Answer :  C

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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 : 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 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 : During DNA replication, the strands separate by (a) DNA polymerase (b) topoisomerase (c) unwindase/helicase (d) gyrase.

Last Answer : b) topoisomerase

Description : DNA fragments are sealed by (A) DNA polymerase II (B) DNA ligase (C) DNA gyrase (D) DNA topoisomerase II

Last Answer : Answer : B

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 : 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 : Ciprofloxacin inhibits (A) DNA topisomerase II (B) DNA polymerase I (C) DNA polymerase III (D) DNA gyrase

Last Answer : Answer : D

Description : DNA polymerase III holoenzyme possesses (A) Polymerase activity (B) 3’→5’ Exonuclease activity (C) 5’→3’ Exonuclease and polymerase activities (D) 3’→5’ Exonuclease and polymerase activities

Last Answer : Answer : D

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

Last Answer : Answer : A

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

Last Answer : Answer : C

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 : 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 : 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 : 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

Last Answer : Answer : D

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

Last Answer : Answer : C

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

Last Answer : Answer : B

Description : During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle like structure at that point. What is that sequence called? (a) AAAT box (b) TATA box (c) GGTT box (d) CAAT box

Last Answer : (c) GGTT box

Description : During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle like structure at that point. What is that sequence called? (a) AAAT box (b) TATA box (c) GGTT box (d) CAAT box

Last Answer : (b) TATA box

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 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 : 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 : 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 : 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 : 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 : 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 : 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 : The transcription initiation factor associated with the RNA polymerase holoenzyme in prokaryotes is (a) β (b) ω (c) σ (d) αI

Last Answer : c) σ (

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

Last Answer : Answer : D

Description : Helicase and DNAB protein cause (A) Rewinding of DNA and require ATP as a source of energy (B) Rewinding of DNA but do not require any source of energy (C) Unwinding of DNA and require ATP as a source of energy (D) Unwinding of DNA but do not require any source of energy

Last Answer : Answer : C

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 : RNA directed DNA polymerase is (A) Replicase (B) Transcriptase (C) Reversetranscriptase (D) Polymerase–III

Last Answer : Answer : C

Description : DNA directed RNA polymerase is (A) Replicase (B) Transcriptase (C) Reverse transcriptase (D) Polymerase III

Last Answer : Answer : B

Description : Replication of nuclear DNA in mammals is catalysed by (A) DNA polymerase α (B) DNA polymerase β (C) DNA polymerase γ (D) DNA polymerase III

Last Answer : Answer : A

Description : RNA primer is formed by the enzyme: (A) Ribonuclease (B) Primase (C) DNA polymerase I (D) DNA polymerase III

Last Answer : Answer : B

Description : Which one is a true statement regarding DNA polymerase used in PCR? (a) It is used to ligate introduced DNA in recipient cells. (b) It serves as a selectable marker. (c) It is isolated from a virus. (d) It remains active at high temperature.

Last Answer : (d) It remains active at high temperature.

Description : Which one is a true statement regarding DNA polymerase used in PCR ? (1) It remains active at hight temperature (2) It is used to ligate introduced DNA in recipient cells (3) It serves as a selectable marker (4) It is isolated from a virus

Last Answer : (2) It is used to ligate introduced DNA in recipient cells

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 : 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 : Enzyme which can break and seal the DNA strand a) Topoisomease II (b) Helicase (c) Primase (d) Restriction endonuclease

Last Answer : a) Topoisomease II

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