question_answer

Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:

Which of the following is correct about urea cycle ? (1) Urea cycle takes place in the liver cells (2) Urea cycle involves the union of two       molecules of ammonia and a molecule of      carbon dioxide (3) Urea is produced by enzyme arginase (4) Three molecules of ammonia enter ornithine cycle

A)  1, 2 and 3 are correct    

B)  1 and 2 are correct

C)  2 and 4 are correct         

D)  1 and 3 are correct

Correct Answer: A

Solution :

                Urea cycle or or nithine cycle or Krebs Henseliet cycle  removes   two   waste   products \[(N{{H}_{3}}andC{{O}_{2}})\] from the blood in liver cells. It involves the union of two molecules of ammonia and a molecule of carbon dioxide and synthesis of urea. All the steps of this cycle are enzymatic and can be visualized as: The enzymes involved in step 1, 2, 3 and 4 respectively are ornithine transcarbanylase, argino succinate synthetase, arginine synthetase and arginase.