Translation and Transcripion

In molecular biology and genetics, translation is the process in which cellular ribosomes create proteins. In translation, messenger RNA (mRNA)—produced by transcription from DNA—is decoded by a ribosome to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell. The ribosome facilitates decoding by inducing the binding of complementary tRNA anticodon sequences to mRNA codons. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is “read“ by the ribosome. The entire process is a part of gene expression. In brief, translation proceeds in four phases: Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon. Elongation: The tRNA transfers an amino acid to the tRNA corresponding to the next codon. Translocation:The ribosome then moves (translocates) to the next mRNA codon to continue the process, creating an amino acid chain. Termination: When a stop codon is reached, the ribosome releases the polypeptide. In bacteria, translation occurs in the cell’s cytoplasm, where the large and small subunits of the ribosome bind to the mRNA. In eukaryotes, translation occurs in the cytosol or across the membrane of the endoplasmic reticulum in a process called vectorial synthesis. In many instances, the entire ribosome/mRNA complex binds to the outer membrane of the rough endoplasmic reticulum (ER); the newly created polypeptide is stored inside the ER for later vesicle transport and secretion outside of the cell. Many types of transcribed RNA, such as transfer RNA, ribosomal RNA, and small nuclear RNA, do not undergo translation into proteins. A number of antibiotics act by inhibiting translation. These include anisomycin, cycloheximide, chloramphenicol, tetracycline, streptomycin, erythromycin, and puromycin. Prokaryotic ribosomes have a different structure from that of eukaryotic ribosomes, and thus antibiotics can specifically target bacterial infections without any harm to a eukaryotic host’s cells. #translation #transcription #DNA #RNA #genetics #ribosomes #anticodon #tRNAs #AminoAcids #endoplasmicReticulum