Most codons in messenger RNA (from DNA) correspond to the addition of an amino acid to a growing polypeptide chain, which may ultimately become a protein. Stop codons signal the termination of this process by binding release factors, which cause the ribosomal subunits to disassociate, releasing the amino acid chain.
V-chip is a generic term for technology used in television set receivers in Canada, Brazil and the USA, which allows the blocking of programs based on their ratings category. It is intended for use by parents to manage their children's television viewing.
All sorts of things go inside this data area -- such as closed captioning information and the time of day -- as well as ratings information. The V-chip simply decodes the line 21 data, compares it with the parent's allowed rating and then either blocks the signal or lets it through. See the next page to learn more.