Molecular Biology-Multiple choice questions (set-2)

Q.1- Which statement best describes the ‘semi-conservative replication’ of DNA?

A) In each replication cycle, only one of the two DNA strands is replicated

B) In each replication cycle, one of the parental strands is conserved

C) In each replication cycle, the daughter cells acquire either the parental stands or new stands

D) Only half of the DNA is replicated in each replication cycle

E) The genetic information is partly conserved in each of the replication cycles.

Q.2- Which of the following enzymes is not involved in DNA replication?

A) Helicase

B) Primase

C) Topo isomerase

D) DNA Polymerase

E) Reverse transcriptase

Q.3- The mobile complex between helicase and primase is called-

A) Prepriming complex

B) Origin replication element

C) DNA unwinding element

D) Primosome

E) Nucleosome

Q.4- The template is read in replication in the-

A) 3’-5’ direction

B) 5’-3’ direction

C) From both the directions

D) Any of these directions

E) None of these directions.

Q.5- The main enzyme to polymerize leading strand of eukaryotic DNA is-

A) DNA polymerase α

B) DNA polymerase β

C) DNA polymerase γ

D) DNA polymerase δ

E) DNA polymerase ∑

Q.6- The prokaryotic DNA chain elongation is carried out by

A) DNA polymerase I

B) DNA polymerase II

C) DNA polymerase III

D) DNA Ligase

E) Topoisomerase II

Q.7- DNA chain growth can be blocked by all of the following agents except-

A) Cytosine arabinoside

B) Zidovudine

C) Acyclovir

D) Dideoxyinosine

E) Chloramphenicol

Q.8- In a newly synthesized prokaryotic DNA strand, the primers are removed by-

A) DNA polymerase I

B) DNA polymerase II

C) DNA polymerase III

D) DNA Ligase

E) Topoisomerase II

Q.9- The 5’-3’ exonuclease activity involves all except-

A) Removal of one nucleotide at a time in the properly base-paired DNA

B) Both ribonucleotides, as well as deoxyribonucleotides, can be removed

C) Groups of altered nucleotides can also be removed

D) Activity is possessed by both DNA pol. I and III

E) DNA repair can also be undertaken by this activity

Q.10- Which of the following eukaryotic DNA polymerases has intrinsic primase activity?

A) DNA polymerase α

B) DNA polymerase β

C) DNA polymerase γ

D) DNA polymerase δ

E) DNA polymerase

Q.11- In the genetic disease, Xeroderma pigmentosum, the cells fail to repair the damaged DNA, due to the defect in the-

A) Direct repair

B) Base excision repair

C) Nucleotide excision repair

D) Mismatch repair

E) Double-strand break repair

Q.12- In a segment of DNA exposed to chemicals Cytosine has been deaminated to Uracil, Which of the following mechanisms will remove Uracil and incorporate the correct base?

A) Direct repair

B) Base excision repair

C) Nucleotide excision repair

D) Mismatch repair

E) Double-strand break repair

Q.13- The promoter region in prokaryotic transcription is recognized by-

A) DNA binding proteins

B) σ Factor of RNA polymerase

C) Single strand binding protein

D) Rho factor

E) β subunit of RNA polymerase

Q.14- Choose the incorrect statement about RNA polymerase-

A) Can not initiate chain synthesis

B) Has no endonuclease activity

C) Has no proofreading activity

D) Utilizes Ribonucleotides only for polymerization

E) Can bind to only double-stranded DNA

Q.15- Actinomycin D, is an inhibitor of transcription, which acts as by inhibiting-

A) β- subunit of prokaryotic RNA polymerase

B) Movement of RNA polymerase along with the DNA template

C) Sigma subunit of RNA polymerase

D) All of the above

E) None of the above.

Q.16– Which of the following processes is not involved in the post-transcriptional processing of t-RNA?

A) Attachment of poly-A tail

B) Trimming

C) Splicing

D) Attachment of CCA arm

E) Base modification

Q.17- Systemic lupus Erythematosus is an autoimmune disorder that results due to the formation of antibodies against snRNPs. What is the function of snRNPs?

A) Attachment of poly-A tail

B) Splicing

C) 5’ capping in m RNA

D) Base modification

E) All of the above.

Q.18- Transcription of a gene in human cells:

A) Always begins at an AUG codon

B) Does not require local unwinding of DNA

C) Always reads the template in the 3’-5’ direction

D) Requires a primer

E) Involves the whole of the DNA

Q.19- The chemical structure of 5’ cap of eukaryotic m RNA cap is-

A) 5- methyl Adenosine triphosphate

B) 7- Hydroxy Guanosine triphosphate

C) 5- methyl guanosine triphosphate

D) 7- methyl guanosine triphosphate

E) 5,7 Dimethyl guanosine triphosphate

Q.20- Choose the incorrect statement about m RNA-

A) Poly (A) tail is added to the 3′ end.

B) Cap is added to the 5’ end.

C) Methylation takes place at 2′-hydroxy and the N⁶ of adenylyl residues.

D) Histone mRNAs lack 5’ cap.

E) Introns are removed and exons are spliced together.

 

Key to Answers

1)- B, 2)- E, 3)- D, 4)- A, 5)- D, 6)-C, 7)- E, 8)-A, 9)- D, 10)- A, 11)- C, 12)- B, 13)- B, 14)- A, 15)-B, 16)- A, 17)-B, 18)- C, 19)- D, 20)- D.