Chapter 26.3, Problem 26.6P

Interpretation Introduction

Interpretation:

The name of bases in the given pentanucleotide has to be given and the fragment is of RNA or DNA has to be predicted.

Concept Introduction:

Composition of nucleic acid: Nucleic acid is a polymer of nucleotides. Each nucleotide has three parts: a sugar, a nitrogenous base, and a phosphate group. Two nucleotides are joined by phosphate diester linkage where a free phosphate on 5’ carbon of one nucleotide and a free –OH group on 3’ carbon of another nucleotide.

Sugar: In both DNA and RNA, sugar portion is found. In DNA, the sugar is D-ribose, where at 2’hydroxyl group is absent and in RNA, the hydroxyl group is present at 2’.

Nitrogenous bases: Five types of nitrogenous bases (has unique one-letter code A, G, T, U, and C) are derived from two parent compounds called purine and pyrimidine. The purine derivatives are Adenine and Guanine are two fused nitrogen containing rings. The pyrimidine derivatives are Thymine, Cytosine, and Uracil are only one nitrogen containing six-membered ring.  Adenine, Guanine, Thymine, and Cytosine are the nitrogenous bases present in DNA. Adenine, Guanine, Cytosine and Uracil are the nitrogenous bases present in RNA.

Nucleotide: (Nucleoside + phosphate)

Nucleotides are the building blocks of nuclei acids; monomers of DNA and RNA polymers. At carbon-5’ of the ribose sugar, a phosphate group is added which is collectively known as nucleotide. Phosphate groups can be added to any of the nucleotide to form diphosphate or triphosphate.