PinkMonkey Online Study Guide-Biology
2. 3 Nucleotides And Nucleic Acid
Every organism reproduces within its life span. This
is accomplished through cell divisions and is regulated by many kinds
of protiens. The information forsynthesizing unique proteins is located
in the nucleus of the cell. It is called the genetic code which
is the "blue print" for producing specific sequences of the
amino acids in proteins. Thus the genetic code can regulate chemical reaction
going on in the cell.
Manís queries into the nature of cells did not end with
its discovery of general structures. In an attempt to understand the chemical
make up and functional details of the cell he succeeded in discovering
a substance called nucleic acid, made up of long chains of nucleotide
It is the structural unit of nucleic acid. Each nucleotide is
(1) Pentose sugar
(2) Phosphate group
(3) One of four nitrogen bases attached to the
pentose sugar. A nucleotide without a phosphate group is a nucleoside.
(B) Nucleic acids
They are complex, large biomolecules formed
of many units called nucleotides.
Nucleic acids are of two types :
(1) DNA - Deoxyribonucleic acid and, (2) RNA - Ribonucleic
The DNA of cells contains genetic information in a coded
form, and is only present in the nucleus of the cellis formed from DNA,
plus a few special organelles. RNA and is present in the cytoplasm and
in the nucleus of the cell.
DNA and RNA differ from one another in their components.
DNA contains the pentose sugar, deoxyribose, while RNA contains ribose.
There are also small differences in the types of nitrogen bases found
in DNA and RNA. (The structure of DNA and its importance in the life of
cells will be explained in the chapter "Genes and Molecular genetics"