Question

From where does urea enter the blood ?

• A. Kidney
• B. Lungs
• C. Liver
• D. None of these

Hint:

Don't mix up the roles of the liver and kidney in urea handling. The Liver Makes urea, and the Kidney Takes urea (out of the blood).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Urea is the primary nitrogenous waste product in mammals. It is produced from the breakdown of proteins and amino acids. The body needs to convert the highly toxic ammonia, a byproduct of this breakdown, into a less toxic substance for transport and excretion.

Step 2: Detailed Explanation:
\[\begin{array}{rl} \bullet & \text{The breakdown of amino acids produces ammonia (\(NH_3\)), which is very toxic to the body. } \\ \bullet & \text{The liver performs a crucial function called the urea cycle. In this cycle, the liver converts toxic ammonia into urea (\(CO(NH_2)_2\)), which is much less toxic. } \\ \bullet & \text{Once produced in the liver, this urea is released into the bloodstream. } \\ \bullet & \text{The blood then transports the urea to the kidneys. } \\ \bullet & \text{The kidneys filter the urea from the blood and excrete it as a component of urine. } \\ \end{array}\] So, urea enters the blood from the liver.

Step 3: Final Answer:
Urea enters the blood from the liver.