Question

In the urea cycle;

	A.	Carbamoyl phosphate is derived directly from glutamine and carbon dioxide
	B.	Ornithine reacts with aspartate to generate argininosuccinate
	C.	The amino group of arginine forms one of the nitrogens of urea
	D.	Ornithine directly reacts with carbamoyl phosphate to form citrulline
	E.	N-acetylglutamate is a positive allosteric effector of Ornithine transcarbamoylase (OTC)

Answer 1

Carbamoyl phosphate is derived directly from glutamine and carbon dioxide

False
In the begining of the urea cycle you need Carbamoyl phosphate to start the cycle.
Its formation is derived from the action of Carbamoyl phosphate synthetase I that uses, bicarbonate, amonia and ATP
(the amonia comes form glutamine and the bicarbonate from CO2, but Carbamoyl phosphate is not directly derived from those)

Ornithine reacts with aspartate to generate argininosuccinate

False

Carbamoyl phosphate reacts whit Ornithine to form citrulline, citrulline will later react whit aspartate and ATP to generate argininosuccinate

The amino group of arginine forms one of the nitrogens of urea

False
Two amino groups are used to form the urea but one comes from aspartate and the other from the ammonia(NH4)
(do understand your teacher's intentions because you could say it obtains both of the N from arginine altho they do not come directly from arginine)

Ornithine directly reacts with carbamoyl phosphate to form citrulline

True
Carbamoyl phosphate reacts whit Ornithine mediated by ornithine transcarbamoylase to form citrulline

N-acetylglutamate is a positive allosteric effector of Ornithine transcarbamoylase (OTC)

False
N-acetylglutamate is in charge of the production of N-acetylglutamic acid that is the one that allosterically activates the action of Carbamoyl phosphate synthetase I