Gene Expression: How DNA Makes Proteins (Animated)

DNA transcription is the first step in gene expression, where genetic information is copied from DNA to RNA.This process takes place inside the cell nucleus.The process begins when the DNA double helix unzips along the gene sequence, exposing the base pairs.RNA polymerase enzyme recognizes and attaches to the promoter region of the DNA.As RNA polymerase moves along the DNA template strand, it creates a complementary messenger RNA strand, matching A with U, and C with G.Once transcription is complete, the messenger RNA exits the nucleus through nuclear pores.The messenger RNA will carry these genetic instructions to the ribosomes in the cytoplasm.In the cytoplasm, messenger RNA carries the genetic instructions for protein synthesis.The ribosome, a molecular machine, recognizes and attaches to the messenger RNA at the start codon, AUG.Transfer RNA molecules, or tRNAs, carry specific amino acids. Each tRNA has an anticodon that matches the corresponding codon on the messenger RNA.The first tRNA carries methionine, which always corresponds to the start codon AUG.As translation continues, the ribosome moves along the messenger RNA, reading each three-letter codon.The next tRNA brings proline, matching its anticodon GGA to the codon CCU.This process continues as the ribosome moves systematically along the messenger RNA.Each codon is matched with its corresponding tRNA, bringing the specific amino acid required for the growing protein chain.The genetic code is read in three-letter units called codons. There are sixty-four possible codon combinations, coding for twenty different amino acids.The ribosome continues this precise process, ensuring accurate translation of the genetic code into a protein sequence.This molecular assembly line continues until a stop codon is reached.As amino acids continue joining together, they form peptide bonds creating a growing polypeptide chain.When the ribosome encounters a stop codon, it signals the end of protein synthesis.The completed polypeptide chain then releases from the ribosome.The protein chain begins its complex folding process, transitioning through various structural stages.Chaperone proteins play a crucial role in this folding process, ensuring the protein achieves its correct shape.Once properly folded, the protein achieves its final three-dimensional structure, ready to perform its specific cellular function.