The genetic code
Genetic information is coded in the sequence of bases in DNA, it is contained in genes. This base sequence directs which amino acids join together and therefore which proteins are made. Enzymes are proteins so it also determines which reactions can take place in an organism.
The genetic code is a triplet code
Experiments showed that a polynucleotide strand always had three timse the number of bases than the amino acid it coded for. If there bases were removed from the polynucleotide strand, the polypeptide chain would be one amino acid shorter. If the polynucleotide had three extra bases, the polypeptide would have one more amino acid.
Experiments showed three bases coded for one amino acid. There are four different bases but over twenty different amino acids occur in proteins.
- If one base coded for one amino acid, only four amino acids could be made
- If two bases coded for one amino acid there'd be 4x4 = 16 combinations to make 16 amino acids which isn't enough.
- If there bases coded for…