1. The first step in the folding of disordered polypeptides into ordered functional protein is the
   formation of ______.
   
   A) 1o structure
   B) 2° structure
   C) 3° structure
   D) 4° structure
   E) hydrogen bonds

B - secondary structure first

2. Evolutionary processes have
   
   A) increased the stability of 4° structures.
   B) decreased the number of subunits.
   C) increased similarity amount 1° structures.
   D) enhanced efficient folding pathways.
   E) all of the above

D - Folding pathways have enhanced thru evolution

3. Chaperonins such as the GroEL/ES system
   
   A) function with thermophilic proteins only.
   B) are required at low pH.
   C) require ATP hydrolysis.
   D) in vitro only.
   E) function in a nonaqueous environment.

C - Chaperons require ATP hydrolysis

4. Which of the following would be most stable based on the information you have learned
   about protein structure?
   
   A) a loop region with 8 amino acids
   B) a β sheet region made up of amino acids Val, Ile, Phe
   C) an α helix made up of Cys, Pro, and Phe
   D) a β hairpin with 12 amino acids
   E) All have equal stability.

B - beta sheet with Val, Ile and Phe will be most stable

5. What structure motif most likely forms as a result of
   this protein sequence?
   
   A) β strand connected to another β strand with a break (or loop/turn) in between
   B) α Helix connect to another α Helix with a break (or loop/turn) in between
   C) β strand connected to another β strand with a alpha helix in between
   D) α Helix connected to a β strand with a break (or loop/turn) in between
   E) None of the above are correct.

D- alpha helix connected to B strand with a break - loop- turn- inbetween

6. Hydrogen bonds and maximum separation of amino acid side chains make the _____very stable and energetically ______________.
   
   A) α helix and β sheet, favorable
   B) α helix, unfavorable
   C) β sheet, unfavorable
   D) α helix, favorable
   E) β sheet, favorable

A- a helix and b sheets are stabalized by H bonds and energetically favorable

7. A chaperonin
   
   A) helps fold some proteins in their lowest energy state.
   B) is required for all proteins to fold properly.
   C) mediates the unfolding of proteins.
   D) is required for protein denaturation.
   E) counteracts the laws of thermodynamics.

A- helps foldingggg

8. A helix has hydrogen bonds between the carbonyl group from residue "n" and the amino group of residue "n+6," which of the following is TRUE?
   
   A) It has 3.6 residues per turn.
   B) It is a random coil, not a helix.
   C) It is an α helix.
   D) It has more residues per turn than an α helix.
   E) It has fewer residues per turn than an α helix.

D- with n+6 will have MORE residues PER TURN then a helix

9. Which of the following contribute to the minimization of energy that occurs with protein folding?
   
   A) orientating amino acid groups to maximize hydrogen bonding
   B) folding hydrophobic groups towards the exterior of the protein
   C) burying polar groups towards the interior of the protein
   D) extensive cavity formation
   E) all of the above

A- orientation of a.a groups is important to keep low energy while folding

10. Which of the following best describes the cause of Creutzfeld-Jakob Disease (a disease which human can develop with symptoms similar to those of mad cow disease)?
    
    A) aggregation of a misfolded protein.
    B) aggregation of random coil regions on a protein.
    C) ingestion of ammonium salts.
    D) the serious side effects of experimental treatment with Quinacrine E) All are potential causes
    Creutzfeld-Jakob disease.

A- aggregating a misfolded protein can cause Jakob