Proteiiniilmentymä

Proteiiniilmentymä refers to the process by which genetic information encoded in DNA is used to synthesize functional protein molecules. This intricate biological process is fundamental to all living organisms and involves two main stages: transcription and translation.

Transcription is the initial step where a specific segment of DNA, a gene, is copied into a messenger RNA (mRNA) molecule. This process occurs in the cell nucleus. Enzymes like RNA polymerase read the DNA sequence and assemble a complementary mRNA strand. The mRNA molecule then carries the genetic code from the nucleus to the cytoplasm.

Translation is the second stage, taking place in the cytoplasm on ribosomes. Here, the mRNA sequence is read in codons, which are three-nucleotide units. Each codon specifies a particular amino acid. Transfer RNA (tRNA) molecules, each carrying a specific amino acid, recognize and bind to the corresponding codons on the mRNA. As the ribosome moves along the mRNA, it catalyzes the formation of peptide bonds between the amino acids, assembling them into a polypeptide chain. This polypeptide chain then folds into a specific three-dimensional structure to become a functional protein. The sequence of amino acids dictates the protein's structure and, consequently, its function within the cell or organism.