And because it's the three dimensional structure of the polypeptide that determines what the function of that polypeptide is the function of that final misfolded protein will not be the same. And usually these types of misfolded proteins are biologically inactive. And what that means is our cells will either denature and break down these proteins or refold them into the correct structure. Now, in some very rare cases these misfolded proteins can actually form these biological molecules we call prions. And prions are very, very dangerous molecules as we'll see in just a moment. Prions are these infectious agents that can actually cause a variety of different types of diseases not only in humans but also in other animals.