Nucleic acids, Biology

Nucleic Acids

Friedrich Miescher  (1868) discovered the presence  of these compound  in protoplasm ,but Altman (1889) introduced the term Nucleic acid. These  acids are the largest  and most  complex compounds of carbon, hydrogen, oxygen, nitrogen and phosphorus, and of most biological  importance, two  type of these occur in biological systems viz.

1. Deoxyribonucleic acid (DNA) and

2. Ribonucleic acid (RNA)

Just as proteins and carbohydrates are polymers respectively of amino acid and monosaccharide units or monomers, nucleic acids are long  chain polymers of nucleotide   monomers (polynucleotide's). This polymerization is also dehydration  compensation  process i.e. nucleotide monomers link together by elimination  of water.

Each Nucleotide molecule is itself a complex compound of nitrogenous organic base  a pentose sugar and a phosphoric acid group linked together by dehydration condensation in two steps. First a base  and sugar molecule link by a n glycoside  bond to form a nucleoside. Then the C5 hydroxyl of the sugar molecule of nucleoside joins with a phosphate group to form a nucleotide molecule. Five nitrogenous bases enter into the composition of various nucleotides. these are of 2 kinds pyrimidine  derivatives with a single ring and purine  derivatives  with  a double ring structure. Pyrimidine derivatives are cytosine, Uracil and thymine. Purine derivatives are Adenine and Guanine. The pentose sugars o nucleotides are  also of two type deoxyribose and ribose .thus the nitrogenous bases, combining with pentose sugars and a phosphate group ,form eight types of nucleotide molecules as follows.

(1)   Cytosine + ribose sugar +phosphate = Cytidylic  acid

(2)   Cytosine +deoxyribose sugar +phosphate=Deoxycytidylic acid

(3)   Uracil+ riboxe sugar + phosphate = Uridylic acid

(4)   Thymine +deoxyribose sugar +phosphate= Thymidylic acid

(5)   Adenine + ribose sugar =phosphate=Adenylic acid

(6)   Adenine+ deoxyribose sugar +phosphate = Deoxyadenylic  acid

(7)   Guanine+ ribose sugar + phosphate = Guanuylic acid

(8)   Guanine+ deoxyribose sugar + phosphate= Deoxyguanylic acid

Posted Date: 9/26/2012 6:55:25 AM | Location : United States







Related Discussions:- Nucleic acids, Assignment Help, Ask Question on Nucleic acids, Get Answer, Expert's Help, Nucleic acids Discussions

Write discussion on Nucleic acids
Your posts are moderated
Related Questions
Infective Endocarditis :  All patients with prosthetic valve come under the high-risk category for endocarditis. They need prophylactic antibiotics if any procedure, which is like

In genetic recombination by crossing over what is the difference between parental gametes and recombinant gametes? The Parental gametes are those gametes that maintain the orig

The internal composition of the cell is maintained because the plasma membrane is selectively permeable to small molecules. A lot of biological molecules are unable to distribute b

How do normal flora protect against infection? a. Compete for space and nutrients with pathogens b. Release antimicrobial agents to kill pathogens c. Contribute to host health by p


Explain Spontaneous Closure of Defects in details? Some defects have a tendency towards spontaneous closure and this can influence the timing of intervention. The defects known

Which are the phases of the menstrual cycle? The menstrual cycle is separated into two main phases: the follicular (or menstrual) phase and the luteal (or secretory) phase.

How can coacervates be formed of phospholipids or polypeptides? Phospholipids are amphipathic molecules, i.e., they present a polar portion and a nonpolar portion. In contact w

Q. What do you mean by ST Hystersis? Ans. The rate of recovery of ST depression has been recognized as a measure of ischaemia severity for many years. When comparing the m

in what form brain stores thinking or past experiences?