Protein Synthesis: Transcription & Translation

From DNA code to functional protein

The Central Dogma describes the flow of genetic information. During transcription, RNA polymerase reads the template DNA strand (3'→5') and synthesizes a complementary mRNA strand (5'→3'), replacing T with U. The mRNA is then processed (5' cap, poly-A tail, intron splicing) before export from the nucleus. During translation, ribosomes read mRNA codons (3-nucleotide sequences) and tRNA molecules deliver the matching amino acids. The ribosome has three sites: A (aminoacyl), P (peptidyl), and E (exit). The polypeptide chain grows until a stop codon (UAA, UAG, UGA) is encountered, releasing the finished protein.