This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Molecular Genetics, Subject name: Biochemistry
[{'content': 'Total number of base pairs in human chromosome: \nSelect and explain. \nA. 3 million, B. 3 billion, C. 3.3 billion, D. 5 million', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: b (3 billion) Ref: Harper, 23rd ed, p. 411Total number of base pairs in haploid (23) human chromosome - 3 billion base pairs.Total number of genes - 30,000. (Harrison, 386)Total number of genes in human chromosome - 1,00,000 genes (Harper)Some useful tips about structure of nucleotides:* Uracil + CH3 (Methylation) - Thymine* Uracil + NH2 (amine) - Cytosine', 'role': 'assistant'}]