PIIA switches AT to the adenylylation mode and it adds adenylyl groups to GS to inhibit it. So PIIA does two things. There are two completely different uses for carbamoyl phosphate. A corepressor is a small molecule like an amino acid that binds to a gene regulatory protein, the aporepressor. By binding it alters the protein structure so it will bind to a gene's promoter and repress its expression.
Many amino acids are corepressors of the committed step enzyme genes.
Amino groups are removed from amino acids in muscle, but it is toxic to transport ammonia in the blood. Describe one way to deliver ammonia from muscle to the liver, so it can be eliminated by the urea cycle. Move to liver. Use glutamate dehydrogenase to deaminate glutamate. Some other creative answers were good for some credit.