mRNA

Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosome, where it is used to produce proteins. The process of producing mRNA is called transcription, which occurs in the nucleus of the cell. mRNA thus plays a crucial role in the central dogma of molecular biology.

Start Codon

A start codon is a sequence of three nucleotides in DNA (or RNA) that signals the beginning of a protein-coding sequence. The most common start codon is AUG, which codes for the amino acid methionine. During translation, the ribosome recognizes the start codon and assembles the protein chain according to the genetic code.

Genetic Code

The genetic code is the set of instructions that determine how proteins are made in a cell. It consists of four nucleotide bases, A, C, G, and T, which combine in groups of three to form codons. Each codon specifies a particular amino acid, which is the building block of proteins.

Stop Codon

Stop codons are sequences of three nucleotides (UAA, UAG, or UGA) in mRNA that signal the termination of protein synthesis. They do not code for any amino acid or have a corresponding tRNA molecule. The presence of a stop codon leads to the release of the newly synthesized protein from the ribosome.