Question

Which is incorrect about the cellular metabolism of -NH2 from amino acids?

Select one:

a. -NH2 is ultimately converted to urea for clearance.

b. -NH2 is converted to carbamoyl phosphate for metabolic process.

c. For the clearance of -NH2, ATP consumption is necessary.

d. For the -NH2 clearance, Asp is not required.

e. The pathway is also used for Arg synthesis.

Answer 1

During the cellular metabolism, Ammonia (-NH2 group) is removed in the form of Urea by Liver through Urea cycle. Because ammonia is neurotoxic and is harmful to body.

In the removal of NH2 (Urea cycle) the steps involved are:-

Formation of Carbamoyl phosphate which then converted into cutrulline

Aspartate is used for the converting citrulline to Argino succinate and uses ATP for the reaction.

Argino succunate is converted into Arginine and then finally Urea is formed which is removed from body through Urine.

Thus, Aspartate(Asp) is not used in NH2 elimination is incorrect statement. Hence option (d) is the answer.

The outline of cycle is given in below image.

Vrea cycle Co₂tNH₃ +2ATP carbamoyl Phosphate Aspartate » citrulline ATP APPARI ornithine Arginosuccinate Ur rea Arginine H₂O Scanned with CamScanner