Question

What molecules make up DNA?

Answer 1

DNA is composed of two polynucleotide chains. These polynucleotide chains coil around each other and form a double helix around each other.

Complete answer:
DNA is one of the four major types of macromolecules, alongside proteins, lipids and polysaccharides and nucleic acids. These macromolecules are all essential for life to exist.
The polynucleotide chains of DNA are made up of simple monomeric units. These units are called nucleotides. Each nucleotide of DNA is made up of nitrogen-containing bases. These nitrogen-containing bases are:
- Cytosine (C)
- Guanine (G)
- Thymine (T)
- Adenine (A)
A nucleotide also consists of a deoxyribose sugar and a phosphate group. The nucleotides of DNA are attached to each other with the help of phospho-diester linkages. These phospho di-ester linkages are located between the deoxyribose sugar of one nucleotide and the phosphate group of the next nucleotide. The backbone of DNA is a sugar-phosphate backbone.
The nitrogenous bases of the polynucleotides of DNA are bound to each other according to the base pair ruling. The base pair ruling states that nitrogenous bases pair in the following sequence:
- Adenine (A) pairs with Thymine (T)
- Cytosine (C) pairs with Guanine (G)

Note:
The double helix of DNA helps carry genetic information for the development, functioning, growth and reproduction for all organisms and several viruses.
The nitrogenous bases bond with each other with the help of hydrogen bonds. This creates a double stranded DNA. The nitrogenous bases are divided into two different groups. These groups are called purines and pyrimidines. The purines in DNA are adenine and guanine and the pyrimidines in DNA are cytosine and thymine.