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Chapter-25 Transcription and Translation

BOOK TITLE: Textbook of Biochemistry for Dental Students

Author
1. Vasudevan DM
2. S Sreekumari
3. Vaidyanathan Kannan
ISBN
9789350254882
DOI
10.5005/jp/books/11333_25
Edition
2/e
Publishing Year
2011
Pages
7
Author Affiliations
1. Faculty of Medicine, Amrita Vishwa Vidyapeetham, (Amrita University), Kochi, Kerala, Formerly Principal, College of Medicine, Amrita, Kerala; Formerly, Dean, Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, Amrita Vishwa Vidyapeetham (Deemed University), Cochin, Kerala, E-mail: dmvasudevan@aims.amrita.edu, PG Programs and Research College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India, College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India; Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, India
2. Jubilee Mission Medical College, Trissur, Kerala, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, Government Medical College, Thrissur and Thiruvananthapuram, Kerala, India; Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India; Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
3. Amrita Institute of Medical Sciences, Kochi, Kerala, India, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala, India, Believers Church Medical College and Hospital, Thiruvalla, Kerala, India
Chapter keywords

Abstract

The template strand is transcribed to mRNA. Transcription is done by RNA polymerase. Transcription has initiation, elongation, termination and post-transcriptional processing. Termination is with the help of Rho factor. Post-transcriptional processing includes removal of introns. Removals of introns are done by spliceosomes. Actinomycin D, mitomycin and rifampicin are inhibitors of RNA synthesis; first two are anti-cancer agents; third is anti-bacterial. Transfer RNA has clover leaf structure. The acceptor arm of tRNA attaches with the amino acid. Opposite side has the anti-codon arm. The 60 S and 40 S subunits combine to form the 80 S mammalian ribosome. Genetic code has the following features: (1) triplet codons, (2) non-overlapping, (3) non-punctuated, (4) degenerate, (5) unambiguous, (6) universal. Translation process is divided into: (1) activation of amino acid, (2) initiation, (3) elongation, (4) termination and (5) post-translational processing. Activation of amino acid needs amino acyl tRNA synthetase; while 2 high energy bonds are used up. One ATP is used for the initiation complex formation, and one GTP for 80 S ribosome formations. Binding of new amino acyl tRNA to a site needs one GTP. Translocation process needs hydrolysis of one GTP. For termination of translation, releasing factor and GTP are required. Post-translational processing includes gamma carboxylation of glutamic acid, and hydroxylation of proline. Tetracyclines, chloramphenicol and erythromycin are bacteriostatic. Streptomycin is bactericidal.

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