Summary Use molecule models to build urea, then model how the kidney removes urea and wastes from the blood for excretion. Science content Biology: Sensing, Organ Systems (4, 5, 6) Activities in this lesson Molecular modelling of urea formation Kidney sorting mechanisms Materials Materials in the activities Procedure Use molecular models to show how ammonia (too toxic to hold in the body for long) is converted to urea. This happens in the liver. Then model the mechanisms used in the kidney for removing urea and other wastes from the blood: filtering, then sorting by shape and diffusion. Grades taught Gr 6
