Question

The DNA strands are antiparallel because of the presence of
A. H-bonds
B. Peptide bonds
C. Disulphide bonds
D. Phosphodiester bonds
E. None of the above

Answer 1

Hint: The nucleic acids store and transfer information needed for the synthesis of specific proteins that determine the structure and functions of the cells. DNA is the genetic material and forms the molecular basis of heredity in all organisms.

Step by step answer:The two chains of DNA molecules run in opposite or antiparallel directions. This means that the carbon atom at position 5 in the sugar component is in one direction in one chain and in the opposite direction in the other chains are parallel but their 5’→3’ directions are opposite.
This is analogous to a 2-lane road, where the lanes run parallel but carry traffic in opposite directions
The two deoxyribonucleotide chains are held together by hydrogen bonds between paired bases and by van der waals attractions between the stacked bases
Adenine of one chain is always joined to thymine of the other chain 2 hydrogen bonds. Cytosine of one chain is always linked to guanine of other chains by 3 hydrogen bonds
Thus there are only four possible base pairs: A-T, T-A, C-G, and G-C in the DNA molecule.
So the correct answer is option A. H-bonds

Note: The complementary bases in DNA molecules and antiparallel directions of the two chains of DNA molecules provide the basis for the precise replication of DNA.
In certain viruses, such as Tobacco Mosaic Virus (TMV), RNA is the genetic material.