Given the task definition and input, reply with output. In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.

Question: For which of the following steps of protein synthesis GTP (Guanosine triosphate) is needed:
Options: <0> Activation of amino acids by aminioacyl-tRNA synthetases. <1> Union of ribosomes to the endoplasmic reticulum. <2> Translocation of nascent tRNA-protein complex from place A to place P. <3> Union of mRNA. <4> Union of signal recognition protein to ribosomes.
chemistry