The genetic code as base triplets in mRNA which code for specific amino acids. The genetic code is universal, non-overlapping and degenerate. The structure of molecules of messenger RNA (mRNA) and transfer RNA (tRNA). Candidates should be able to compare the structure and composition of DNA, mRNA and tRNA.

Candidates should be able to compare the structure and composition of DNA, mRNA and tRNA.

The sequence of bases on mRNA is the genetic code. Each set of three bases corresponds to the bases on one tRNA molecule (the anticodon) the top of the tRNA molecule is attached to an amino acid, in this way every triplet of bases- called a codon- codes for an amino acid.

The genetic code is:

• Universal- it is the same in all organisms
• Non-overlapping- each base is read only once
• Degenerate- amino acids have several different codons that code for them

tRNA is a folded strand that creates a shape with the anti-codon on one side and the attachment site for an amino acid on the other.