The proposed cause of CJD and kuru in humans, mad cow disease, and scrapie in sheep is a change in a brain protein. Disease victims appear to have a protein that should normally contain alpha helices but instead they have changed into a protein made of beta pleated sheets. The disease appears to spread when the abnormal protein comes into contact with the normal protein, causing it to become deformed. Which level of protein structure is associated with these diseases?

A) primary
B) secondary
C) tertiary
D) quaternary
E) molecular

Beta Pleated Sheets

A structural motif in proteins characterized by zigzag folding of the peptide chain, contributing to the protein's overall stability.

Alpha Helices

A common structural motif in proteins where the polypeptide chain forms a coiled structure stabilized by hydrogen bonds between backbone atoms.

Protein Structure

The three-dimensional arrangement of atoms in an amino acid-chain molecule. Proteins have a complex structure, including primary, secondary, tertiary, and quaternary formations, that determines their function in biological systems.