Transcription translation protein synthesis12/24/2023 The process of translation or protein synthesis. The end product of translation is a polypeptide chain which folds and undergoes post translational modifications to form a functional protein. Usually in prokaryotes the mRNA formed is polycistronic and in eukaryotes it is monocistronic. The end product of transcription is an RNA transcript which can form any of the following types of RNA: mRNA, tRNA, rRNA and non-coding RNA (like microRNA). In translation when the ribosome encounters one of the three stop codons it disassembles the ribosome and releases the polypeptide. In eukaryotes when a termination sequence is encountered the RNA nascent transcript is released and it is poly-adenylated. Transcription termination in prokaryotes can either be Rho-independent, where a GC rich hairpin loop is formed or Rho-dependent, where a protein factor Rho destabilizes the DNA-RNA interaction. The process hence proceeds in a 5’ to 3’ direction. The peptide then moves one codon position to get ready for the next amino acid. The ribosome subunit, three initiation factors (IF1, IF2 and IF3) and methionine carrying t-RNA bind the mRNA near the AUG start codon.ĭuring translation the incoming aminoacyl t-RNA binds to the codon (sequences of 3 nucleotides) at A-site and a peptide bond is formed between the new amino acid and the growing chain. Translation initiates with the formation of initiation complex. It is in this stage that RNA polymerase unwinds the DNA. The promoter consists of a core region like the TATA box where the complex binds. The transcription factors and RNA polymerase binding to the promoter forms a transcription initiation complex. Transcription initiates with RNA polymerase binding to the promoter region in the DNA. Translation is performed by a multi-subunit structure called ribosome which consists of rRNA and proteins. It can be inducible as seen in the spatio-temporal regulation of developmental genes or consitutive as seen in case of house keeping genes like Gapdh. Transcription is performed by RNA polymerase and other associated proteins termed as transcription factors. In eukaryote transcription occurs in the nucleus and translation occurs in ribosomes present on the rough endoplasmic membrane in the cytoplasm. In prokaryotes both transcription and translation occur in the cytoplasm due to the absence of nucleus. Translation is inhibited by anisomycin, cycloheximide, chloramphenicol, tetracyclin, streptomycin, erythromycin and puromycin.įound in prokaryotes' cytoplasm and in a eukaryote's nucleusįound in prokaryotes' cytoplasm and in eukaryotes' ribosomes on endoplasmic reticulum Transcription is inhibited by rifampicin and 8-Hydroxyquinoline. It then proceeds in a 5' to 3’ direction. Peptide then moves one codon position to get ready for the next amino acid. The incoming aminoacyl t-RNA binds to the codon at A-site and a peptide bond is formed between new amino acid and growing chain. RNA polymerase elongates in the 5' -> 3' direction When the ribosome encounters one of the three stop codons it disassembles the ribosome and releases the polypeptide. DNA rewinds itself into a double-helix and is unaltered throughout this process. RNA transcript is released and polymerase detaches from DNA. Occurs when ribosome subunits, initiation factors and t-RNA bind the mRNA near the AUG start codon. Promoter directs the exact location for the initiation of transcription. Occurs when RNA polymerase protein binds to the promoter in DNA and forms a transcription initiation complex. MRNA, tRNA, rRNA and non-coding RNA( like microRNA)Ī 5’ cap is added, a 3’ poly A tail is added and introns are spliced out.Ī number of post-translational modifications occur including phosphorylation, SUMOylation, disulfide bridges and farnesylation. Uses rRNA as assembly plant and tRNA as the translator to produce a protein. This is the second step of gene expression. Translation is the synthesis of a protein from an mRNA template. Uses the genes as templates to produce several functional forms of RNA The purpose of translation is to synthesize proteins, which are used for millions of cellular functions. The purpose of transcription is to make RNA copies of individual genes that the cell can use in the biochemistry. Comparison chart Transcription versus Translation comparison chart
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