BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Deoxyribo-nucleic Acid (DNA) consists of simple sugar, phosphate and four nitrogen bases.

Detailed explanation-2: -Phosphate Backbone A phosphate backbone is the portion of the DNA double helix that provides structural support to the molecule. DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.

Detailed explanation-3: -Nucleotide A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T).

Detailed explanation-4: -DNA consists of a pair of chains of a sugar-phosphate backbone linked by pyrimidine and purine bases to form adouble helix (Fig. 96.1). The sugar in DNA is deoxyribose. The pyrimidines are cytosine (C) and thymine (T); the purines are guanine (G) and adenine (A).

Detailed explanation-5: -Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine and thymine; in RNA, uracil is used in place of thymine.