This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Guanosine triphosphate (GTP) is required by which of the following steps in protein synthesis? \nSelect and explain. \nA. Aminoacyl-tRNA synthetase activation of amino acids, B. Attachment of ribosomes to endoplasmic reticulum, C. Translocation of tRNA-nascent protein complex from A to P sites, D. Attachment of mRNA to ribosomes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: . Translocation of tRNA-nascent protein complex from A to P sites. Two molecules of GTP are used in the formation of each peptide bond on the ribosome. In the elongation cycle, binding of aminoacyl-tRNA delivered by EF-Tu to the A site requires hydrolysis of one GTE Peptide bond formation then occurs. Translocation of the nascent peptide chain on tRNA to the P site requires hydrolysis of a second GTE The activation of amino acids with aminoacyl-tRNA synthetase requires hydrolysis of ATP to AMP plus PPi.', 'role': 'assistant'}]