Codons

Definition

Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids or stop signals during protein synthesis. They are essential components of the genetic code, which directs the assembly of proteins in cells.

5 Must Know Facts For Your Next Test

1. There are 64 possible codons, but only 20 amino acids, leading to redundancy in the genetic code.
2. AUG is the start codon and also codes for the amino acid methionine.
3. UAA, UAG, and UGA are stop codons that signal the end of protein synthesis.
4. Each codon is read sequentially from a specific starting point on the mRNA.
5. The correct reading frame is crucial; shifting it by even one nucleotide changes the entire sequence of amino acids.

Review Questions

Related terms

mRNA:

Messenger RNA (mRNA) carries genetic information from DNA to ribosomes for protein synthesis.

tRNA:

Transfer RNA (tRNA) brings amino acids to ribosomes according to codon sequences in mRNA.

Ribosome: A cellular organelle that facilitates the translation of mRNA into proteins by linking amino acids together.