MCBG - Post-Translational Modification (Secretory Pathway) Flashcards Preview

CJ: UoL Medicine Semester One (ESA1) > MCBG - Post-Translational Modification (Secretory Pathway) > Flashcards

Flashcards in MCBG - Post-Translational Modification (Secretory Pathway) Deck (21):
1

What sort of secretion is collagen?

Constitutive

2

What sort of secretion is insulin?

Regulated

3

Give some examples of proteins delivered via the constitutive secretory pathway.

Immunoglobulins, albumin, prohormones, collagen, fibronectin, laminin, receptors

4

Give some examples of proteins delivered via the regulated secretory pathway.

Insulin, glucagon, beta-endorphin, ACTH, alpha-MSH, beta-lipotropin, trypsin

5

Where does the word "collagen" come from?

Greek "kolla" meaning glue

6

True or false - collagen is the most abundant protein in the body.

True - 25%-35% of all proteins

7

Which cells produce collagen?

Fibroblasts

8

How many polypeptide chains make up tropocollagen?

3 alpha polypeptide chains, each roughly 1000 aa long

9

True or false - collagen has a glycine in every fourth position along each alpha chain?

False - it's every third position

10

Give some characteristics of the triple helix structure of collagen.

- non-extensible
- non-compressible
- high tensile strength

11

Why is glycine the only amino acid that could be in the alpha chain in collagen?

Only amino acid with side chain small enough

12

The basic pattern of the alpha chain is this:

(Gly-X-Y)n

What is X usually?

Proline or hydroxyproline, can also be some Y positions

13

What shape is tropocollagen?

300nm rod-shaped

14

How are the alpha chains linked?

H-bonds

15

What does prolyl hydroxylase require to work?

Vitamin C and Fe2+

16

What is the result of having weak tropocollagen triple helices due to insufficient vitamin C?

Scurvy

17

How does prolyl hydroxylase strengthen the triple helices?

Hydroxylates residues, leading to formation of more H-bonds

18

What does lysyl oxidase require to work?

Vitamin B6 and Cu2+ ions

19

What does lysyl oxidase do?

Forms covalent cross-links between tropocollagens.

20

Why is tropocollagen secreted before final processing occurs?

It is too big and would destroy the cell if it were assembled within it

21

Which disorder can arise due to mutation in collagen or lysyl oxidase deficiency?

Ehlers-Danlos Syndrome (EDS)

Decks in CJ: UoL Medicine Semester One (ESA1) Class (55):