2.3.7 - Fibrous Proteins: Structure & Function

Question 1

Describe The Structure Of Fibrous Proteins
(5 Points)

Answer 1

~ Are long strands of polypeptide chains, which have cross linkages due to hydrogen bonds.

~ Insoluble, tightly coiled around each other to form a rope shape.

~ Have little to no tertiary structure.

~ Have limited number of amino acids with a highly repetitive sequence, creating organised structures.

~ Their chains are held together by strong bonds such as hydrogen and disulphide bonds, making them strong.

Question 2

Describe The Function Of Fibrous Proteins
(2 Points)

Answer 2

~ Insoluble, due to a large number of hydrophobic R groups.

~ Strong, alongside their insolubility property make them suitable for structural roles, often found in supportive tissue.

Question 3

What Are Examples Of Fibrous Proteins?
(3 Points)

Answer 3

~ Keratin -> Makes up hair, nails and feathers.

~ Elastin -> Found in connective tissues, tendons, skin and bone.

~ Collagen -> Connective tissue found in skin, tendons and ligaments.

Question 4

Describe The Structure Of Collagen
(4 Points)

Answer 4

~ Made of 3 polypeptide chains forming a triple helix, held by hydrogen bonds.

~ Every third amino acid is glycine, its small size allows chains to pack tightly together.

~ Hydrogen bonds between chains, and covalent cross-links between R groups, forms fibrils.

~ Staggered arrangement of collagen molecules in fibrils gives a striated pattern.

Question 5

Describe The Function Of Collagen
(4 Points)

Answer 5

~ High tensile strength, due to hydrogen bonds in the triple helix.

~ Staggered fibril arrangement, increases strength.

~ Insoluble in water, as its long molecule length makes it slow to dissolve.

~ Flexible, supports connective tissues while maintaining strength.