Transcript Protein Synthesis

Protein Synthesis
The way in which DNA controls the
cell is by controlling how enzymes
and other proteins are synthesized.
Since these molecules regulate the
chemical reactions of the cell, they
control many aspects of cell function.
Codons
• George Gamow postulated that a three-letter
code must be employed to encode the 20
standard amino acids used by living cells to
encode proteins.
• 4 bases in groups of 2 gives 4^2 = 16
combinations, while 4 bases in groups of 3 gives
4^3=64 combinations.
• This was verified experimentally during the
1060’s by Marshall Nirenberg and Heinrich J.
Matthaei
Codon table
• Codon tables allow us to associate a
codon with its particular amino acid.
• Most codon tables use RNA codons.
• Each sequence of three bases codes for one
amino acid, and is known as the triplet code.
• The triplet code allows for up to 64
permutations known as codons
The Genetic Code – How many stop codons
are there?
3