Structure of DNA and RNA
The DNA or Deoxyribonucleic Acid is the hereditary material in an organism. Located in the nucleus of the cell, the DNA is related to storing and maintaining the information needed to create a new organism. Whenever an organism reproduces, a portion of the DNA replicates and is passed on to the offspring.
RNA or Ribonucleic Acid, similar to DNA, is the genetic material that relates to the synthesis of protein and replaces the DNA in some viruses.
STRUCTURE
A DNA strand is divided into units known as nucleotides. Each nucleotide has three basic components — A pentose sugar, a phosphate molecule and a nitrogenous base.
PENTOSE SUGAR: Pentose is the scientific term for a simple sugar molecule that has five carbon atoms. The main purpose of a pentose sugar in the DNA is its formation. Deoxyribose, the pentose found in a strand of DNA, is used to synthesize nucleotides and nucleic acids (genetic material such as DNA and RNA).
PHOSPHATE MOLECULE: The phosphate molecules gives the DNA its backbone structure. It bonds with the pentose to form a sugar-phosphate molecule which gives in turn, bonds with other sugar-phosphate bonds to give the DNA its structural integrity.
NITROGENOUS BASES: Nitrogenous Bases are molecules that have nitrogen in them and possess the properties a base .i.e neutralizes acids by reacting with them to form water and a salt. The two backbone sugar-phosphate strands are connected by a series of four nitrogenous bases in the DNA: Adenine, Guanine, Thymine and Cytosine.
The bases are divided into two categories- Purines and Pyrimidines. While bonding, purines and pyrimidines can only bond with each other. In a nucleotide, Adenine and Guanine are purines while Thymine and Cytosine are pyrimidines. In a RNA strand, Thymine is absent. Instead, an alternate pyramidine, Uracil, is present.
Adenine only bonds with Thymine in a double hydrogen bond while Guanine bonds with Cytosine in a triple hydrogen bond.
Multiple nucleotides build up to form a single DNA strand. In a strand, the order and sequence by which the bases are arranged determine the unique feature or hereditary material that that particular DNA transmits, essentially like the DNA being a blueprint and the sequence of the bases being the data or information.
