Genetic code

Definition

The genetic code is a set of rules by which information encoded in DNA or RNA sequences is translated into proteins by living cells. It determines how sequences of nucleotides correspond to specific amino acids.

5 Must Know Facts For Your Next Test

1. The genetic code consists of 64 codons, each made up of three nucleotide bases.
2. It is nearly universal across all organisms, meaning the same codon specifies the same amino acid in most cases.
3. There are start and stop codons that signal the beginning and end of protein synthesis; AUG is a common start codon.
4. The genetic code is redundant, with multiple codons coding for the same amino acid, but it is not ambiguous - each codon specifies only one amino acid.
5. Mutations in the genetic code can lead to changes in protein structure and function, potentially causing diseases.

Review Questions

• What are the components that make up a codon in the genetic code?
• Why is the genetic code described as 'redundant' but not 'ambiguous'?
• What are the roles of start and stop codons in protein synthesis?

Related terms

Codon:

A sequence of three nucleotides that together form a unit of genetic code.

tRNA:

Transfer RNA; type of RNA that carries amino acids to the ribosome during translation.

Ribosome:

A complex molecular machine found within all living cells that performs biological protein synthesis (translation).