Urea Synthesis And Its Role In Protein Metabolism

Urea Synthesis And Its Role In Protein Metabolism

Question 1. Describe the urea cycle and its disorders/inborn errors.

Answer:

Urea cycle:

• It is the first metabolic cycle described by Hans Krebs and Kurt Her select.
• Thus, it is known as Krebs – Henseliet cycle.
• Urea is a synthesized liver.
• It has two amino groups.
  • Derived from ammonia.
  • Second, derived from aspartate.
• It requires five enzymes.

Urea cycle Steps:

Urea cycle Disorders/Inborn Errors:

Question 2. What is a normal blood urea level? Describe the synthesis and fate of urea in our body.
Answer:

Normal Blood Urea Level:

• In healthy individuals, the normal blood urea level is 10 – 40 mg/ dl.

Normal Blood Urea Level Synthesis:

Normal Blood Urea Level Fate:

1. Urea produced gets easily diffused and is transported by the blood to the kidneys excreted in the urine.
2. A small amount of it enters the intestine.
   • Here it gets degraded to CO2 and NHg by urease.
   • Ammonia thus formed is excreted in feces or absorbed by tire blood.

Question 3. What is Urea? Enumerate the steps in its synthesis. Mention its significance.
Answer:

Urea:

• It is the end product of protein metabolism.
• B 80 – 90% of the nitrogen-containing substances excreted in urine contain urea.
• It has two amino groups – one from ammonia and the other from aspartate.

Steps in Urea Synthesis:

1. Synthesis of carbamoyl phosphate.
2. Formation of citrulline
3. Synthesis of arginosuccinate
4. Cleavage of arginosuccinate
5. Formation of urea.

Urea Significance:

• Blood urea is used as a screening test for the evaluation of kidney function.
• Elevation in blood urea is categorized into.
  1. Pre-renal
  2. Renal
  3. Post-renal.