Proteins, encoded by individual genes, orchestrate nearly every function of the cell.
The Central Dogma describes the flow of genetic information from DNA to RNA to protein.
The genetic code is a degenerate, non-overlapping set of 64 codons that encodes for 20 amino acids and 3 stop codons.
RNA polymerase initiates transcription at specific DNA sequences called promoters.
Transcription elongation begins with the release of the polymerase σ subunit and terminates via the rho protein or via a stable hairpin.
Initiation is the first step of eukaryotic transcription and requires RNAP and several transcription factors to proceed.
Elongation synthesizes pre-mRNA in a 5' to 3' direction, and termination occurs once RNAPII encounters a poly-A tail.
Eukaryotic pre-mRNA receives a 5' cap and a 3' poly-A tail before introns are removed and the mRNA is considered ready for translation.
rRNA and tRNA are structural molecules that aid in protein synthesis but are not themselves translated into protein.
Protein synthesis, or translation of mRNA into protein, occurs with the help of ribosomes, tRNAs, and aminoacyl tRNA synthetases.
Protein synthesis involves building a peptide chain using tRNAs to add amino acids and mRNA as a blueprint for the specific sequence.
In order to function, proteins must fold into the correct three-dimensional shape, and be targeted to the correct part of the cell.