Translation

ID #2410

I don't understand the point of elongation factors. Are these connected to the first tRNA as well as all of them? or all but the first tRNA?


The first tRNA will have initiation factors attached, rather than elongation factors. 
Each subsequent tRNA will have elongation factors instead. In this case, we are talking about EF-tu. The incoming elongation factors bring energy with them (in the form of GTP) and help to provide a form of quality control for the charged tRNAs coming into the A site. Remember, any charged tRNA can come into that site. But, only the tRNA with the right anticodon to match the codon on the mRNA will "fit" perfectly. That perfect fit will move the elongation factor's GTP into a cleft where it will be cleaved. The energy from that cleavage makes the elongation factor release its tRNA and leave the ribosome entirely. (The GDP and inorganic phosphate also leave the ribosome.) 

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