Question

In Ornithine cycle, which of the following wastes are removed from the blood?

• A. Urea and urine
• B. Ammonia and urea
• C. $CO_{2}$ and ammonia
• D. $CO_{2}$ and urea

Answer 1

Answer: (C)

$CO_{2}$ and ammonia

Answer 2

Mammals are ureotelic organisms. In these organisms the ammonia deposited in the mitochondria of liver cells is converted into urea in the Omithine cycle or urea cycle. Hans Kreb discovered this cycle in $1932$ (who later also discovered citric acid cycle). Urea production is occurred almost exclusively in liver and it passes into blood stream and then to kidneys. During excretion of this urea through kidneys, $CO_{2}$ is also excreted.