Central Dogma in Biology: DNA to Protein Explained

DNA, or deoxyribonucleic acid, is the molecule that carries genetic instructions for development and functioning of living organisms.The DNA double helix consists of two strands connected by complementary base pairs. Adenine pairs with Thymine, and Guanine pairs with Cytosine.During transcription, RNA polymerase attaches to the DNA and begins to unzip the double helix.As RNA polymerase moves along the DNA, it creates a complementary messenger RNA strand. In RNA, the base Uracil replaces Thymine.Notice how in the messenger RNA, Uracil takes the place of Thymine in base pairing with Adenine.Once transcription is complete, the messenger RNA will carry these genetic instructions out of the nucleus.The messenger RNA will now undergo processing before it can be used to make proteins.After transcription, the newly formed pre-messenger RNA undergoes several important modifications.The pre-messenger RNA contains both coding regions called exons, and non-coding regions called introns.A complex called the spliceosome removes the introns and joins the exons together.A protective cap is added to the five-prime end of the messenger RNA.And a string of adenine nucleotides, called a poly-A tail, is added to the three-prime end.The nuclear pores are specialized channels that allow the mature messenger RNA to exit the nucleus.The processed messenger RNA, now called mature messenger RNA, moves through the nuclear pore into the cytoplasm.In the cytoplasm, the mature messenger RNA will be ready for protein synthesis at the ribosomes.In the cytoplasm, ribosomes act as the protein-making factories of the cell.The ribosome reads messenger RNA in groups of three nucleotides called codons.Transfer RNA molecules bring specific amino acids to match each codon sequence.The first codon, AUG, signals the start of protein synthesis and codes for the amino acid methionine.As each new tRNA arrives, it brings its specific amino acid to the growing protein chain.Peptide bonds form between amino acids, creating a growing protein chain.This process continues step by step as the ribosome moves along the mRNA.And that's how cells synthesize proteins, one amino acid at a time!