The question is referring to the hexosamine pathway.
out of curiosity, how may people knew this? (dont be shy to say you did or didnt?)
My poverty education didn't ingrain this in me.
I tried to use logic to answer this question (I did not know about the hexosamine pathway). Here is my attempt--this is probably wrong somewhere.
I figured that if you want to make glucosamine, you need to combine glucose + an amine group
(A) Arginine I knew was involved in donating nitrogen, but it is in the urea cycle, so I figured this was probably not the answer but it had potential. I figured that the major way this compound removes its nitrogen is through urea, though.
(B) ATP. Since F6P already has the phosphate group, I figured ATP is probably not necessary as the compound in question already has a PO4 group.
(C) Carbamoyl phosphate. I knew this was involved in both the urea cycle and nucleoside synthesis, so this was less likely. It also is the product of a NH3 and CO2 so that means that I wouldn't expect it to donate an amine group
(D) Glutamine I figured has an amine group attached to it ready for donation. I also know that transamination reactions are common with amino acids and alpha-ketoacids (e.g. alpha ketoglutarate with alanine can get you glutamate and a pyruvate via ALT) thus it made sense that an amino acid could donate an amine group.
(E) The only thing I knew about NAG was that it was used in the urea cycle as an allosteric activator of CPS, so I didn't think that it was useful as a donator of nitrogen since its function is to help aid nitrogen excretion.
So then I was stuck between A and D, but based on transamination reactions, I picked D.
you need to add an amine (nitrogen) and most biochem processes from sugar --> amine requires glutamine
If you want to take a look for the clinical importance of the hexosamine pathway & products: https://www.sciencedirect.com/topics/neuroscience/hexosamines
Process of elimination on this one.