(general) The beginning of a state or of a process; the act of initiating
In general sense, the term initiation pertains to the beginning of a state or of a process. In biology, the term may be applied to the start of a biological process. For instance, translation, a step in protein biosynthesis wherein the genetic code carried by mRNA is decoded to produce the specific sequence of amino acids in a polypeptide chain, begins when a small subunit of the ribosome binds to the 5′ end of mRNA with the help of initiation factors. This step is referred to as initiation. Nevertheless, prior to initiation, the process of translation would proceed or start when the correct amino acid binds to the correct tRNA, a process called activation. Following initiation, the next step would be elongation (i.e. when the next aminoacyl-tRNA in line binds to the ribosome along with GTP and an elongation factor) and ends with termination (i.e. when the A site of the ribosome encounters a stop codon). Initiation is also the first step in the process of gene transcription, the process of transcribing or making a copy of genetic information stored in a DNA strand into a complementary strand of mRNA.
- Initiation codon
- Initiation factor
- Initiation complex
- Initiation trna