Protein synthesis involves two complex processes called transcription and translation which involve a variety of different components and structures to function correctly.
Before we begin, here are some terms which you should familiarise yourself with.
Transcription occurs in the nucleus and is the process in which DNA is transcribed into mRNA.
Firstly, a specific section of DNA unwinds and unzips, exposing the nucleotides. Then, RNA polymerase, an enzyme responsible for initiating and catalysing this process, binds to the promoter region located on the template strand. By using free floating RNA nucleotides, RNA polymerase synthesises a strand of primary mRNA (pre-mRNA) via complementary base pairing. Once the nucleotide sequence at the end of the gene signals to stop transcription, the pre-mRNA sequence is released. Then, the mature mRNA molecule exits the nucleus via nuclear pores and binds to a ribosome. (Ribosomes are composed of rRNA, ribosomal RNA, and proteins)
Post transcriptional factors facilitate the conversion of pre-mRNA into mature mRNA and only occur in eukaryotic organisms.
Translation occurs at a ribosome and is the process in which mRNA is translated into a protein. Proteins which are synthesised at free-floating ribosomes in the cytosol are used within the cell, while those produced on the rough endoplasmic reticulum are secreted for use outside of the cell.
Once the mRNA strand exits the nucleus it binds to a ribosome, it begins to synthesise the polypeptide chain once the start codon is recognised. Active tRNA molecules bring specific amino acids to the mRNA-ribosome complex. The anticodon on the tRNA molecule temporarily binds with the complementary codon, releasing the amino acid which forms a peptide bond with an adjacent amino acid. This continues until a stop codon appears and the polypeptide chain is released.