Which of the characteristics of collagen structure listed below contribute to the tensile strength of collagen?
I. Collagen is made up of a triplet helix where 3 left-handed helices twist together in a right handed sense.
II. Collagen includes a repeating sequence of amino acids with glycine every 3 amino acids in a helix with about 3 amino acids per turn.
III. The three left-handed helices are staggered to allow close packing between glycine residues and rigidity from the bulky and inflexible proline/hydroxyproline.
a. I
b. I and II
c. I, II, and III
d. IIand III
e. I and III
