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: Biochemistry
[{'content': 'Smallest unit of genetic expression \nSelect and explain. \nA. Gene, B. Cistrone, C. Codon, D. Genetic code', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Cistrone Gene :- It is the smallest functional unit of genome. Gene is the unit of DNA that carries the information for synthesis of specific protein. Cistron:- It is smallest unit of genetic expression. It is the basic genetic unit coding for one polypeptide chain, i.e., a subunit of a complete protein molecule. It is regarded as one cistron-one subunit concept. Prokaryotic mRNA is polycistronic, i.e. each mRNA has several coding region. Eukaryotic mRNA is monocistronic, i.e. each mRNA has single coding region. Smallest functional unit of genome - gene, codes for a specific protein. Smallest unit of genetic expression - cistron, (codes for the subunit of protein, i.e. one polypeptide chain).", 'role': 'assistant'}]