D.
Protein A is a structural component while Protein B is an enzyme. The secondary structures
of both proteins are studied. (Questions 16-19)
16._____
Which could be characteristics of Protein A and Protein B?
a)
Protein A could have a low energy conformation while Protein B could
have a high energy conformation.
b)
Protein A could be a globular protein while Protein B could be a fibrous
protein.
c)
Protein A could contain mainly
α
-helix while Protein B could contain
equal amounts of
α
-helix and
β
-sheet.
d)
Protein A could be a type of collagen while Protein B could be a type of
keratin.
17._____
Which could be found within the structure of Protein B?
a)
A disulfide bond could form between two prosthetic groups.
b)
A salt bridge could form between two chaperones.
c)
Protein B could contain areas of random secondary structure stabilized by
van der Waals forces.
d)
Protein B could contain areas of repeating secondary structure stabilized
by hydrogen bonds.
18._____
Which is a characteristic of both an
α
-helix and a
β
-pleated sheet?
a)
Both can be anti-parallel structures.
b)
Both form interactions involving the oxygens of peptide bonds.
c) Both are found only within multimeric proteins.
d)
Both are denatured when heat breaks peptide bonds.
19._____
Which is a difference between an
α
-helix and a
β
-pleated sheet?
a)
An
α
-helix is a right-handed structure containing disulfide bonds while a
β
-pleated sheet is a left-handed structure containing ionic bonds.
b) An
α
-helix has a relatively extended spiral shape while a
β
-pleated sheet has
a relatively compact zig-zag shape.
c) An
α
-helix has non-covalent bonds between amino acids near each other
in the sequence while a
β
-pleated sheet has non-covalent bonds between
amino acids far apart in the sequence.
d)
An
α
-helix contains mainly amino acids with polar R-groups while a
β
-
pleated sheet contains mainly amino acids with non-polar R-groups.
_____________________________________________________________________________
