Saturday, 9 August 2014

NUCLEIC ACIDS:: PART 2

NITROGENOUS BASES

-          These are most important constituent of both DNA and RNA.

-          These are classified into two groups based upon their structure.

-          PYRIMIDINES

o   It is heterocyclic (a cyclic compound with more than one type of atoms) compound.

o   Pyrimidines constitute of three nitrogenous bases

o   Thymine: -
§  Found only in DNA.
§  Chemical composition C5H6O2N2.
o   Cytosine: -
§  Found both in DNA and RNA.
§  Chemical composition is C4H5ON3.
                    
o   Uracil: -
§  Found only in RNA.
§  Chemical composition is C4H4O2N2.

-          PURINES

o   It is a pyrimidine ring that is attached to another 5-membered ring.

o   Purines constitute of two nitrogenous bases.

o   Adenine: -

§  Found both in DNA and RNA.
§  Chemical composition is C5H5N5.
          
o   Guanine: -
§  Found both in DNA and RNA.

§  Chemical composition is C5H5ON5.

No comments :