Its a very simple question really, yet the answers are obviously complex (like everything in biochemistry) how do I allow my organisms to tolerate ammonia yet still be carbon based by altering their biochemistry. Are nucleic acids and amino acids broken/degraded by Ammonia? what causes hyperammonaemia in Terran life-forms? The last post I asked was perhaps a bit broad and complex, but I've narrowed it down from a broad range of topics to just one. My solvent is an Ammonia-Water mixture (2-3% ammonia) and I want lifeforms that can at least tolerate it.
You can use a similar system that bacterium use currently to keep from being attacked by otherwise lethal bases/acids: a non-reactive lipid layer that doesn't allow for the importation of ammonia past the layer. Receptors or biological pumps can be used to import biological nutrients or water without allowing overly toxic amount of ammonia into the organism.