Nucleic Acids
Function:
Structure, Functional
Structure:
Varies
Nucleic acids are polymers of nucleotides; thus nucleic acids
are called polynucleotides
Two major classes of nucleotides.
1) DEOXYRIBONUCLEIC ACID (DNA)
DNA is the chemical basis for the gene, the fundamental unit of
inheritance; mostly found in the nuclei of cells.
2) RIBONUCLEIC ACID (RNA)
RNA molecules are close copies of genes mostly found in the
cytoplasm of cells.
Nucleotides:
A nucleotide consists of:
i) a nitrogen base
(either a purine or a pyrimidine)
• In DNA, there are two purine bases adenine and guanine
used to make nucleotides
• In DNA, there are two pyrimidine bases: thymine and
cytosine used to make nucleotides
• In RNA, thymine does not occur--it is replaced by the
pyrimidine uracil
Pyrimidines
(single ring)
Purines
(double ring)
ii) a 5-carbon sugar (in DNA it is deoxyribose; in RNA it is
ribose)
(in RNA)
(in DNA)
iii) a phosphate group
A nucleic acid polymer consists of alternating chains of sugar
and phosphate with a nucleotide base attached to a
deoxyribose sugar