TRANSLATION _ PART 01

For more information: http://www.7activestudio.com [email protected] http://www.7activemedical.com/ [email protected] http://www.sciencetuts.com/ [email protected] Contact: +91- 9700061777, 040-64501777 / 65864777 7 Active Technology Solutions Pvt.Ltd. is an educational 3D digital content provider for K-12. We also customise the content as per your requirement for companies platform providers colleges etc . 7 Active driving force "The Joy of Happy Learning" -- is what makes difference from other digital content providers. We consider Student needs, Lecturer needs and College needs in designing the 3D & 2D Animated Video Lectures. We are carrying a huge 3D Digital Library ready to use. Molecular Basis of Inheritance:TRANSLATION: Arrangement of amino acids in a linear, specific sequence and formation of polypeptide chain according to the specific sequence of information written on m-RNA is called translation changing the code language on m-RNA into the language of amino acids. Translation occurs in the cytoplasm. The primary requirements for translation process are ribosomes, m-RNA, t-RNA, amino acids, enzymes, ATP, GTP and specific activators. The process of translation involves,1Activation of amino acids - its transfer to t-RNA. 2. Initiation of polypeptide chain. 3Elongation of polypeptide chain and. 4 Chain termination. 5Activation of amino acids and its transfer to t-RNA:Amino acids are activated by ATP in the presence of an enzyme known as amino acyl synthetase and linked to their cognate t-RNA, a process called as charging of t-RNA or amino acylation of t-RNA. As a result amino acyl t-RNA is formed which moves towards ribosomes.AA amino acid + ATP + Enzyme amino acyl synthetase→ AA + AMP + Enzyme Complex + PP pyrophosphateAA-AMP-Enzyme complex + t-RNA → AA-t-RNA complex + AMP + enzyme Amino acyl t-RNA. 2. Initiation of polypeptide chain:AUG is the initiation codon of m-RNA. It codes for Methionine. Formyl group is attached to free amino group of methionine. The t-RNA bringing formyl methione is called f.met. t-RNA and it acts as initiator.As the anticodons of t-RNA are complementary to the codons of m-RNA they can develop loose hydrogen bonds with codons of m-RNA. Ribosomes have two sites for t-RNA: 1Aminoacyl or acceptor site or "A"site 2Peptidyle site or "P" site in the larger sub- unit. Aminoacyl t-RNA first binds to A-site of ribosomes & move to P-site while initiator t-RNA first binds to p-site.The initiator amino acyl t-RNA in the presence of m-RNA combines with sub units of ribsomes. This process requires energy.3.Elongation of polypeptide chain: Chain elongation takes place by the establishment of peptide bonds between the amino acids as the ribosomes move along m-RNA one codon at a time in 51 →31 direction. Depending on the second codon of m-RNA, the t-RNA with anticodon complementary to the codon of m-RNA forms a complex with the corresponding activated amino acid and moves to the ribosomes and binds at the 'A' site. This is facilitated by elongation factor & energy in the form of GTP.Formyl methionine in P-site establishes a peptide bond with the second amino acid at 'A' site. Polypeptide chain grows in C→ N direction.carboxyl group of first amino acid and amino group of second amino acid). Peptide bond is catalysed by the enzyme peptidyl transferase.After the bond formation ribosomes move to the next codon of m-RNA. This movement of ribosomes relative to m-RNA resulting in the shift of peptidyl t-RNA from 'A' site to 'P' site is called translocation.Translocation requires translocase & GTP. Therefore aminoacyl t-RNA enters 'A' site and moves to 'P'site after developing peptide bond. 1 Chain termination: When the terminating codons UAA, UAG or UGA present in m-RNA, it indicates the end of polypeptide synthesis. They do not code for any amino acid and hence no amino acid enters 'A' site and thus they act as stop signals. At the end, a relative factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.