Fibrous Proteins

Question 1

What are fibrous proteins?

Answer 1

-long stands of polypeptide chains - have cross linkages due to H bonds
-no tertiary structure
-limited no.of amino acids - highly repetitive sequence

Question 2

Examples of fibrous proteins

Answer 2

-keratin
-elastin
-collagen

Question 3

What is collagen?

Answer 3

-most common structural protein found in vertebrates
-provides structural support
-forms tendons, cartilage, skin and the walls of blood vessels

Question 4

What is the structure of collagen?

Answer 4

-formed from 3 polypeptides chains held together by H bonds = triple helix
-each chain is a helix shape - contains amino acids
-PS = every 3rd amino acid is glycine

Question 5

What are the functions of collagen?

Answer 5

-flexible structural protein
-forming connective tissues
-lots of H bonds = great tensile strength
-stable protein
-length of collagen molecule = too long to dissolve in water (insoluble)

Question 6

What is keratin?

Answer 6

-found in hair + fingernails
-strong and soluble in water
-high proportion of cysteine = strong

Question 7

What is elastin?

Answer 7

-skin, walls of arteries
-long cross linked strands - containing hydrophobic regions
-when stretched - spring back together