Question

In ornithine cycle which of the following wastes are removed from the body?
A) $CO_2$ and Urea
B) Ammonia and urea
C) Urea and urine
D) $CO_2$ and ammonia

Answer 1

Ornithine cycle which is also called an urea cycle is a series of biochemical reactions that occurs in the liver of the body and converts the highly toxic compounds into less toxic compounds before their excretion out of the body.

Complete answer
Urea cycle or ornithine cycle was the first metabolic cycle described by Hans Krebs and Kurt Henseleit in 1932. The primary centre for the occurrence of this cycle is the liver of the body and only a lesser extent of it occurs in the kidneys of the body.

Let us analyze the options to find out the correct answer.
Option A: In the urea cycle, $CO_2$ and ammonia are removed out of the body in the form of urea. Therefore, this is the incorrect option.

Option B: Ammonia is the toxic product removed out of the body in the form of urea during the ornithine cycle.Therefore, this is the incorrect option.

Option C: Urea is formed from the conversion of ammonia in the liver during urea cycle and is secreted out of the body in form of urine.Therefore, this is the incorrect option.

Option D: Ornithine cycle functions to remove the toxic products formed during the amino acid catabolism. Ammonia is the highly toxic product formed during the amino acid catabolism and $CO_2$ from the blood is also removed from the body through this cycle. Urea cycle converts the ammonia into a less toxic form called urea which is excreted by the kidneys in the form of urine.Therefore, this is the correct option.

Thus, the correct answer is option (D) $CO_2$ and ammonia.

Note: The enzymes and other molecules present in the livers convert the ammonia and carbon dioxide and convert it into urea and in each cycle two molecules of ammonia and one molecule of carbon dioxide is removed from the body.