MCQ on Nucleic Acids - DNA and RNA | Biochemistry MCQs

1. From the following, identify the persons credited with the discovery of nucleic acid

A) Erwin Chargaff

B) James Watson, Maurice Wilkins, and Francis Crick

C) William Raux

D) Frederick Meischner

 

2. The Watson-Crick double helix model describes the structure of: 

A) A-DNA

B) Z-DNA

C) B-DNA 

D) Triplex DNA

 

    3.  According to Rodley and Sasi model, DNA is

A) Right-handed

B) Left-handed

C) Alternating right and left-handed helix

D) None of these 

    4. Rosalind Franklin’s pictures of DNA the double helix was taken using the technique known as

A) Diffraction

B) X-ray crystallography

C) Fluorescence

D) Transmission electron microscopy  

5. Choose the statements which are correct about tRNA:

1. tRNAs have a guanylate residue at the 5’end and a trinucleotide sequence CCA at the 3’ end

2. tRNAs have a 7-methylguanosine residue at the 5’end and a trinucleotide sequence CCA at the 3’ end 

3. Aminoacyl-tRNA synthetases attach correct amino acids to their tRNAs 

4. Peptidyl transferase attach correct amino acids to their tRNAs 

A) 1 & 3 only 

B) 1 only

C) 1 & 4 only

D) 2 & 3 only  

 

6. Choose the statement which is NOT true about negatively supercoiled DNA 

 A) Negatively supercoiled DNA is underwound

 B) There are fewer base pairs per helical turn 

 C) It has fewer helical turns than the linear or relaxed molecule 

 D) Most DNA isolated from natural sources is negatively supercoiled

7. Ethidium bromide is an: 

A) Chelating agent

B) Intercalating agent 

C) Reducing agent

D) Oxidizing agent

8. The left-handed, Zig-Zag double helix DNA, with only minor grooves is

A) B-DNA

B) A-DNA

C) Z-DNA

D) Both A-DNA and B-DNA

9. RNA – DNA hybrid always adopt A form because of

A) Steric hindrance of – OH group in RNA

B) Steric hindrance of – OH group in DNA

C) Coiling of the molecule

D) Presence of Uracil base in RNA

10.The RNAs present in 80S Eukaryotes chromosomes

A) 23S rRNA, 5S rRNA and 16S rRNA

B) 28S rRNA, 5S rRNA, 5.8S rRNA and 18S rRNA

C) 28S rRNA, 5S rRNA and 16S rRNA

D) 23S rRNA, 5S rRNA and 18S rRNA

Learn more: Biomolecules MCQs

Answers

1. D) Frederick Meischner

2. C) B-DNA 

3. C) Alternating right and left-handed helix

4. B) X-ray crystallography

5. A) 1 & 3 only 

6.  B) There are fewer base pairs per helical turn 

7. B) Intercalating agent 

8. C) Z-DNA

9. A) Steric hindrance of – OH group in RNA

10. B) 28S rRNA, 5S rRNA, 5.8S rRNA and 18S rRNA