Extra Cellular Matrix

Question 1

Fibrillar

Answer 1

contains fibres

Question 2

Which kind of tissues are rich in ECM?

Answer 2

connective

Question 3

how many chains make up collagen? What type? What structure do they form?

Answer 3

3 alpha chains, triple helix

Question 4

collagen is most abundant in which 3 tissues?

Answer 4

bone, tendon, skin

Question 5

type 1 collagen is made up of?

Answer 5

heterotrimer - 2 x alpha 1 (I) , 1 x alpha 2 (I)

Question 6

type 2 collagen is made up of?

Answer 6

homotrimer - 3 x alpha 1 (II)

Question 7

type 3 collagen is made up of?

Answer 7

homotrimer - 3 x alpha 1 (III)

Question 8

why is glycine small enough to occupy interior of triple helix?

Answer 8

side chain is hydrogen

Question 9

what is the primary sequence of collagen?

Answer 9

glycine x-y repeat

Question 10

in a glycine x-y repeat, which amino acids usually take up x and y?

Answer 10

x - proline

y - hydroxyproline

Question 11

why is proline important in the structure of collagen?

Answer 11

undergoes hydroxylation for interchain H bond formation

Question 12

lysine and hydroxylysine are similarly modified as proline for what?

Answer 12

hydroxylation for H bond cross linkeages

Question 13

Does cross linking occur before or after collagen is excreted?

Answer 13

after

Question 14

what is vitamin C required for?

Answer 14

co-factor for

prolyl and lysl hydroxylases

Question 15

deficiency in vitamin C leads to what?

Answer 15

underhydroxylated collagens leading to tissue instability (scurvy)

Question 16

what are the collagen precursors called?

what modifications do they undergo?

Answer 16

pro alpha chains
covalent
folding into triple helix
cleavage of ends
fibril formation

Question 17

which modification occurs after the collagen is secreted from the cell?

Answer 17

crosslinking

Question 18

tropocollagens form fibrils (parallel bundles), providing?

Answer 18

tensile strength

Question 19

Ehlers-Danlos syndromes (EDS) can be due to what exactly? Symptoms?

Answer 19

collagen deficiency
loose joints
stretchy skin

Question 20

what is special about type 4 collagen

Answer 20

non fibril forming

Question 21

non fibril forming collagens form networks by?

Answer 21

associating head to head, tail to tail, and laterally

Question 22

where are basement membranes present? Made of?

Answer 22

• underneath epithelial sheets and tubes
• surround muscle, peripheral nerve and fat cells
• made of ECM

Question 23

what happens to the ECM and where, in diabetic nephropathy?

Answer 23

glomerular basement membrane highly thickened due to accumulation of ECM. Restricts filtration.

Question 24

alport syndrome, which mutation? results in?

Answer 24

collagen 4, results in loss of kidney function and hearing

Question 25

alport syndrome caused by mutation in collagen 4, caused by?

Answer 25

abnormally split and layered glomerular basement membrane

Question 26

elastic fibres are interwoven with collagen for what reason?

Answer 26

limit stretching

Question 27

elastic fibres are a core of _____ surrounded by _____ rich in ____

Answer 27

elastin
microfibrils
fibrillin

Question 28

FIBRILLIN is secreted by? What is it?

Answer 28

fibroblasts, glycoprotein

Question 29

mutations in fibrillin 1 result in _____ sydrome

Answer 29

Marfan’s syndrome

Question 30

name 2 common multi-adhesive glycoproteins

Answer 30

laminins

fibronectin

Question 31

laminins are ______ and contain chains _____, ______ and _____

Answer 31

alpha
beta
gamma

Question 32

multi-adhesive glycoproteins interact w/ cell surface receptors

Answer 32

integrins, dystroglycan