Briefly describe translation process
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Translation is the process of synthesis of protein. It converts language of nucleic acid to the language of protein language.
It is divided into three phases: initiation, elongation and termination.
Messenger RNA (mRNA) is produced from the transcription.
Transfer RNA (tRNA) is known as the interpreter. It interprets mRNA genetic information into amino acid. It pairs amino acids with mRNA codons by using anticodons.
Anticodons is the triplet of bases which is complementary to mRNA codon triplet.
Ribosomes are the organelles that coordinate the synthesis of polypeptides. It is made of two subunits and each subunit is made of proteins and ribosomal RNA (rRNA).
Three phases of translation are initiation, elongation and termination.
1. Initiation is the first phase of translation. It binds mRNA with two ribosome subunits. The cap and tail of mRNA molecule helps the mRNA to bind with the ribosome.
mRNA molecule binds to a small ribosomal subunit and then initiator tRNA binds to the start condon.
A larger ribosomal subunit binds to the small subunit and results in complete functional ribosome.
2. Elongation is the second phase of translation and involves three steps:
a) Recognizing codon: The incoming tRNA has an anticodon that pairs with mRNA codon which is at the A site of the ribosome. Anticodon pairs with a complementary triplet on mRNA. For instance, if mRNA has the codon UUU, the tRNA’s sequence is complementary which means AAA.
b) Peptide bond formation. The polypeptide then leaves the tRNA in the P site and attaches to the amino acid which is present on the tRNA in the A site. The ribosome catalyzes the formation of bond between two amino acids.
c) Translocation: The P site tRNA then leaves the ribosome. The tRNA that carries the polypeptide moves from the A to the P site
3. Termination is the third step that occurs when stop codon reaches the ribosomes at A site. Complete polypeptide is then freed and the ribosome again splits into its two subunits.
- 18 Jul 2020 @ 12:21