Extra Cellular Matrix Flashcards

1
Q

Fibrillar

A

contains fibres

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2
Q

Which kind of tissues are rich in ECM?

A

connective

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3
Q

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

A

3 alpha chains, triple helix

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4
Q

collagen is most abundant in which 3 tissues?

A

bone, tendon, skin

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5
Q

type 1 collagen is made up of?

A

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

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6
Q

type 2 collagen is made up of?

A

homotrimer - 3 x alpha 1 (II)

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7
Q

type 3 collagen is made up of?

A

homotrimer - 3 x alpha 1 (III)

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8
Q

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

A

side chain is hydrogen

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9
Q

what is the primary sequence of collagen?

A

glycine x-y repeat

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10
Q

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

A

x - proline

y - hydroxyproline

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11
Q

why is proline important in the structure of collagen?

A

undergoes hydroxylation for interchain H bond formation

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12
Q

lysine and hydroxylysine are similarly modified as proline for what?

A

hydroxylation for H bond cross linkeages

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13
Q

Does cross linking occur before or after collagen is excreted?

A

after

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14
Q

what is vitamin C required for?

A

co-factor for

prolyl and lysl hydroxylases

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15
Q

deficiency in vitamin C leads to what?

A

underhydroxylated collagens leading to tissue instability (scurvy)

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16
Q

what are the collagen precursors called?

what modifications do they undergo?

A
pro alpha chains
covalent
folding into triple helix
cleavage of ends
fibril formation
17
Q

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

A

crosslinking

18
Q

tropocollagens form fibrils (parallel bundles), providing?

A

tensile strength

19
Q

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

A

collagen deficiency
loose joints
stretchy skin

20
Q

what is special about type 4 collagen

A

non fibril forming

21
Q

non fibril forming collagens form networks by?

A

associating head to head, tail to tail, and laterally

22
Q

where are basement membranes present? Made of?

A
  • underneath epithelial sheets and tubes
  • surround muscle, peripheral nerve and fat cells
  • made of ECM
23
Q

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

A

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

24
Q

alport syndrome, which mutation? results in?

A

collagen 4, results in loss of kidney function and hearing

25
alport syndrome caused by mutation in collagen 4, caused by?
abnormally split and layered glomerular basement membrane
26
elastic fibres are interwoven with collagen for what reason?
limit stretching
27
elastic fibres are a core of _____ surrounded by _____ rich in ____
elastin microfibrils fibrillin
28
FIBRILLIN is secreted by? What is it?
fibroblasts, glycoprotein
29
mutations in fibrillin 1 result in _____ sydrome
Marfan's syndrome
30
name 2 common multi-adhesive glycoproteins
laminins | fibronectin
31
laminins are ______ and contain chains _____, ______ and _____
alpha beta gamma
32
multi-adhesive glycoproteins interact w/ cell surface receptors
integrins, dystroglycan