This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of Purines and Pyrimidines, Subject name: Biochemistry
In humans, end product of purine metabolism - 
Select and explain. 
A. Allantoin, B. Uric acid, C. CO,, D. None
B: Uric acid
Answer: B: Uric acid 
Explanation: Ans. is 'b' i.e., Uric acid Catabolism of purine nucleotideso Humans catabolize purines (adenine and guanine) to uric acid.o In mammals other than higher primates (in non primate mammals), uric acid is converted to water soluble allantion by enzyme 'uncase'. However, human lack uricase, therefore the end product of purine catablism is uric acid, which is excreted.