Final answer:
The triple helix found in collagen is the type of protein secondary structure that is known for being highly extensible due to its coiled nature. Collagen is the type of protein secondary structure that is highly extensible due to its coiled structure.
Step-by-step explanation:
The type of protein secondary structure that is characterized as being highly extensible because of its coiled structure is the triple helix found in collagen. Collagen has a unique triple helical structure which provides its characteristic strength and the ability to be stretched without being broken. The type of protein secondary structure that is characterized as being highly extensible because of its coiled structure is Collagen.
Collagen is a fibrous protein found in connective tissues such as skin, tendons, and bones. Its coiled structure allows for flexibility and strength, making it highly extensible. This structure is different from alpha helices and beta sheets, which are more rigid and structured forms of protein secondary structures. Alpha helices are spiral structures stabilized by hydrogen bonds, and beta sheets consist of stretched out strands lying alongside each other, also stabilized by hydrogen bonds.