Explain the structure of the DNA molecule. In your answer include the parts that make up the molecule, how these parts are organized, the shape of the molecule and the relationship between DNA molecules and chromosomes.

Answer and Explanation:

The nucleic acid that forms chromosomes is called deoxyribonucleic acid (DNA). DNA is ade up of structural units called nucleotides. Each nucleotide consists of three components linked together by covalent bonds. These are a five-carbon sugar called deoxyribose, a phosphate group and a nitrogenous organic base. The organic bases are four kinds: adenine, guanine, cytosine and thymine.

The nucleotides of DNA are covalently linked to one another forming long polynucleotide chains. The various bases stick out from the backbone at regular intervals forming variable part of the DNA molecule. The linking of bases across the two chains also called base pairing is specific in that adenine will only pairs with thymine and guanine will only pair with cytosine.