Molecular Basis of Inheritance: MCQ Test

1. Which nucleic acid primarily functions as the genetic material in most organisms?

• DNA
• RNA
• Protein
• Lipid

2. Besides acting as a genetic material in some viruses, what additional roles does RNA perform?

• Adapter
• Structural
• Catalytic molecule
• All of the above

3. What defines the length of DNA?

• Number of nucleotides
• Number of base pairs
• Number of sugar-phosphate units
• Both A and B

4. What is the haploid content of human DNA in base pairs?

• 5386 nucleotides
• 48502 bp
• 4.6 × 10^6 bp
• 3.3 × 10^9 bp

5. A nucleotide has which of the following three components?

• A nitrogenous base
• A pentose sugar
• A phosphate group
• All of the above

6. Which of the following nitrogenous bases is found in DNA but not in RNA?

• Cytosine
• Uracil
• Thymine
• Adenine

7. How are two nucleotides linked to form a dinucleotide?

• N-glycosidic linkage
• Phosphoester linkage
• 3'-5' phosphodiester linkage
• Hydrogen bonds

8. What is referred to as the 5’-end of a polynucleotide chain?

• A free OH of 3'C group
• A free phosphate moiety at 5'-end of sugar
• A nitrogenous base
• A pentose sugar

9. What additional group is present in RNA at the 2'-position in the ribose of every nucleotide residue compared to DNA?

• -CH3 group
• -NH2 group
• -OH group
• -PO4 group

10. Who first identified DNA as an acidic substance in the nucleus and named it ‘Nuclein’?

• James Watson
• Francis Crick
• Friedrich Meischer
• Erwin Chargaff

11. The Double Helix model for DNA structure was proposed by James Watson and Francis Crick based on X-ray diffraction data produced by whom?

• Maurice Wilkins and Rosalind Franklin
• Erwin Chargaff
• Friedrich Meischer
• Matthew Meselson and Franklin Stahl

12. Erwin Chargaff observed that for a double-stranded DNA, the ratios between which base pairs are constant and equal one?

• Adenine and Guanine
• Cytosine and Uracil
• Adenine and Thymine
• Guanine and Uracil

13. The base pairing in DNA confers what unique property to the polynucleotide chains?

• They are identical to each other
• They are complementary to each other
• They can only form single strands
• They are always parallel

14. If each strand from a parental DNA acts as a template for synthesis of a new strand, what will be the nature of the two double-stranded daughter DNA molecules produced?

• Identical to the parental DNA
• Half-identical to parental DNA
• Completely different from parental DNA
• Partially complementary to parental DNA

15. What is the polarity of the two polynucleotide chains in the DNA double helix?

• Parallel
• Anti-parallel
• Both 5'->3'
• Both 3'->5'

16. In the DNA double helix, how many hydrogen bonds form between Adenine and Thymine, and Guanine and Cytosine, respectively?

• 2 and 2
• 3 and 2
• 2 and 3
• 3 and 3

17. The two DNA chains are coiled in what fashion, and what is the approximate pitch of the helix and number of base pairs per turn?

• Left-handed, 3.4 nm, 10 bp
• Right-handed, 3.4 nm, 10 bp
• Left-handed, 0.34 nm, 10 bp
• Right-handed, 0.34 nm, 10 bp

18. What is the approximate distance between a base pair in a DNA helix?

• 3.4 nm
• 0.34 nm
• 10 nm
• 1.0 nm

19. What factors contribute to the stability of the DNA helical structure?

• Hydrogen bonds
• Stacking of base pairs
• Sugar-phosphate backbone
• Both A and B

20. Francis Crick proposed the Central Dogma in molecular biology, which states that genetic information flows in what direction?

• Protein → RNA → DNA
• RNA → DNA → Protein
• DNA → RNA → Protein
• DNA → Protein → RNA