Question
What is the end product of catabolism of pyrimidine:
| A. |
NH3
|
| B. |
CO2 & H2O
|
| C. |
Both A & B
|
| D. |
None
|
Show Answer
|
Correct Answer » C
Explanation
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|
Unlike purines, which are degraded to uric acid, pyrimidines are completely broken down into soluble end products.
Pyrimidines Involved
End Products of Pyrimidine Catabolism
The degradation of pyrimidines ultimately produces:
- Carbon dioxide (CO₂)
- Water (H₂O)
- Ammonia (NH₃)
Additionally:
- Uracil and cytosine yield β-alanine
- Thymine yields β-aminoisobutyrate
These intermediates are further metabolized and excreted.
Therefore, both NH₃ and CO₂/H₂O are end products of pyrimidine degradation.
