BIOL 1414 Midterm: Test 3
Document Summary
Are pieces of rna with no protective coating. Somehow, these have agents are resistant to rnases in the environment. Infect plants and cause diseases in those plants. Do cause disease in humans and other mammals. There are just protein, no nucleic acid involved. So, they are made by a host gene and exist in the host normally. The protein is made up of several helical areas where the amino acids wind around like a staircase. Sometimes (though genetic predisposition or bad luck or another prion) this normal protein changes shape into one that is pleated (like a fan)-not helical. This is the prion form of the protein. Importantly, this prion polymerizes with other copies of the pleated form to make long fibers that kill neurons. The prion comes into the body through eating an animal that has prions. Alternatively, the change from normal to prion can change spontaneously (at a very low rate-one in a million people per year)