Q4. "Structure drives function" and this is certainly the case with proteins. (12 points total) a. What are two driving forces for protein folding? ( 2 points) b. Describe all 4 levels of protein structure. (4 points) c. For secondary structure, there are two common motifs. Please name them and draw their structures. (4 points) d. Membrane proteins are integral to the attachment of cells to ECM and engineered biomaterials. A membrane protein must have a domain that passes through the membrane. Assuming this domain is an -helix, design a transmembrane domain by considering the local environment and the height/length of the protein needed to pass the membrane (5nm). ( 2 points)