For use in (aerobic) respiration, polypeptides would first be hydrolysed to their amino acid monomers. These are each deaminated, i.e. have their amino groups removed, producing an organic acid, which can be fed into the Kreb's Cycle, and a waste product, ammonia (NH₃), which is moved to the liver and removed from the blood.
When you cut your hand your body reacts to it as a stimulus
So stimulus
Bending over and touching your toes describes flexion in reference to your intervertebral discs.
