biochem quiz 1 collagen/elastin

Question 1

name the alpha helix disruptors

Answer 1

glycine and proline

Question 2

what is the function of collagen

Answer 2

major function is structural. found in skin, blood vessels, bone. Fibrous protein secreted from the cell.

Question 3

What is the structure of collagen?

Answer 3

Collagen has quatranery structure and contains 3 alpha helical chains, more than one polypeptide chain. Type 1 most abundant.

Question 4

what are fibril forming collagens?

Answer 4

types 1, 2 , and 3 form connective tissue, cartilage, bone , blood vessels

Question 5

what is tropocollagen?

Answer 5

The basic unit of collagen, contains three intertwined chains . Primary structure contains gly-x- pro-y- oh/pro chain . secondary structure has extended left handed helix and requ. proline.

Question 6

What does glycine do in support of tropocollagen structure?

Answer 6

Glycine allows the packing of the three chains in tropocollagen formation, intra H bonds stabilize in quatranery structure.

Question 7

why is hydroxyproline important to collagen structure?

Answer 7

stabilizes collagen triple helix , enzyme requires ascorbic acid. vit c ** stabilizes extended helix

Question 8

what is the role of hydroxylysine?

Answer 8

stabilizes cross links in collagen fibers, carb addition, requires vitamin c, ascorbic acid.

Question 9

what are the roles of collagen fibrils?

Answer 9

end up outside of the cell, striated pattern, light gap holes . nucleation site, site of covalent x linking in lysine residues.

Question 10

what parts of collagen processing occurs intracellularly?

Answer 10

removal of signal sequence, formation of disulfide bonds between alpha chains, hyrdoxylation CHO addition, triple helix formation, secretion

Question 11

what parts of collagen processing occur extracellularly?

Answer 11

removal of propeptides and the N and C termini, fibril formation/crosslinking,

Question 12

where does cross linking of lysine residues occur?

Answer 12

outside of the cell. lysyl oxidase outside the cell forms the crosslink

Question 13

Where are mutations more severe?

Answer 13

At carboxy end

Question 14

What is the role of elastin?

Answer 14

extracellular matrix proteins. rubber like. Plays a role in lungs, arteries, ligaments . Rich in glycine, proline, and lysine. without elastin, alveoli cannot expand.

Question 15

How is collagen secondary structure different from an alpha helix?

Answer 15

glycine and proline- alpha helix disruptors. every 3 aa in collagen is gly. different extended left handed helices that requires proline.

Question 16

Can structure of collagen form intra h bonds?

Answer 16

NO

Question 17

Where does the winding of collagen structure begin?

Answer 17

C terminus

Question 18

what forms the cross linking outside of the cell during collagen processing?

Answer 18

lysol oxidase OUTSIDE OF CELL

Question 19

Why is glycine important to collagen structure?

Answer 19

every 3rd AA is glycine . Collagen is tropocollagen, triple helix that is held close together by glycine. Winding starts at carboxy terminus and winding is essential to tropocollagen formation.