|
Genetic Code
The set of triplet code words in DNA coding for all
of the amino acids. There are more than 20 different
amino acids and only four bases (adenine, thymine,
cytosine, and guanine). The mRNA code is a triplet
code, that is, each successive "frame" of three
nucleotides (sometimes called a codon) of the mRNA
corresponds to one amino acid of the protein. This
rule of correspondence is the genetic code. The
genetic code consists of 64 entries- the 64 triplets
possible when there are four possible nucleotides,
each of which can be at any of three places (4 x 4 x 4
= 64). A triplet code was required because a doublet
code would have only been able to code for (4 x 4 =
16) sixteen amino acids. A triplet code allows for the
coding of 64 theoretical amino acids. Since only a
little over 20 exist, there is some redundancy in the
system. Hence some certain amino acids are coded for
by two or three different triplets.
MESSENGER RNA (mRNA), DEOXYRIBONUCLEIC ACID (DNA), INFORMATIONAL MOLECULES, CODING SEQUENCE, CODON |
