This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Amino Acids Basics, Subject name: Biochemistry
[{'content': 'Selenocysteine is derivative of which aminoacid - \nSelect and explain. \nA. Serine, B. Alanine, C. Arginine, D. Glycine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is \'a\' i.e., Serine o Selenocysteine is considered as 21" standard amino acid. o It is present at the active site of some enzymes that catalyze redox reactions, e.g. thioredoxin reductase, glutathione peroxidase, and the deiodinase (converts thyroxin to triiothyronine). o Biosynthesis of selenocysteine requires cysteine, serine, ATP and a specific t-RNA o Serine provides the carbon skeleton of selenocysteine. o Selenocysteine has a structure similar to cysteine, but containing the trace element selenium in place of sulfur atom of cysteine.', 'role': 'assistant'}]