Question

The two long polynucleotide chains of DNA are held together by

• A. Hydrogen bonds
• B. Covalent bonds
• C. Metallic bonds
• D. Ionic bonds
• E. Polar covalent bonds

Answer 1

The correct option is A Hydrogen bonds

DNA is a double helical molecule made of two antiparallel strands of nucleotides which is linked by hydrogen bonds between complementary base pairs. DNA carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms. Adenine (A) pairs with Thymine (T) via two hydrogen bonds. Guanine (G) pairs with Cytosine (C) via three hydrogen bonds. Hence option A is correct.