Urea Cycle. It is made for B.Sc Nursing 1st Year student.

1. UREA CYCLE
Rajdip Majumder
Tutor.
Institute of Nursing,
Brainware University

2. Introduction
• It is the process by which ammonia that is
highly toxic substance, is converted to urea,
which is less toxic water soluble, excrete waste
product in the liver.

3. OVERVIEW
• When protein breakdown in our body it of course breakdown
into amino acids. Amino acid is known for protein building
block.
• When amino acid catabolised (break down) they form
ammonia(NH3). Ammonia is not a problem for healthy body
but problem occur when we can’t get ammonia outside the
body because it increase toxic level.
• Ammonia is sent in liver and turn into urea. Urea sent to the
kidney and eliminated.

5. Urea Cycle

6. Reactions of the urea cycle
1.Ammonia combine
with Co2 and
formed carbamoyl
phosphate and
enzyme catalyse
the reaction is
carbamoyl
phosphate
synthetase-1

7. Reactions of the urea cycle
2. Carbamoyl phosphate
combine with ornithine
to form citrullin. This
reaction catalyzed by
ornithine
transcarbamylase.
N.B: till now those
reaction occurs in
Mitochondria.

8. Reactions of the urea cycle
3. Citrulline now combine
Asparate ATP and form
Arginino succinate.
This reaction catalyzed
by Arginino succinate
synthase.
4. Arginino succinate form
Arginine and in this
process split off
Fumarate as a by
product and catalyzed
this reaction is
Arginino succinase.

9. Reactions of the urea cycle
5. Arginine will go back to
ornithine. In this
process it will convert
Urea. And this urea go
through kidney and
excreated.