Collagen

Question 1

3 main tissues in connective tissues

Answer 1

1. collagen
2. elastin
3. proteoglycans

Question 2

3 main properties of collagens

Answer 2

1. tensile strength
2. compression resistance
3. specialized networks

Question 3

what is at ends of collagens

Answer 3

registration peptides

Question 4

featuure of collagen chain

Answer 4

Gly-X-Y

Question 5

What allows 3 helix structure

Answer 5

registration peptides @ C-terminal + Gly/x/y repeat

Question 6

what keeps strand together after peptides cleaved off

Answer 6

H-bond > tropocollagen

Question 7

what links 2 triple chains

Answer 7

lysine and hydroxylysine covalent crosslinks

Question 8

what a group of many chains together create

Answer 8

quarter stagger array

Question 9

3 types of collagen fiber org. and their locations

Answer 9

1. unidirectional - tendon
2. random - skin
3. orthoganal - cornea

Question 10

what happens if don’t convert proline to hydroproline

Answer 10

no H-bonds - loose joints, teeth fall out, weak bones - scurvy

Question 11

what is needed to convert proline to hydroxyproline

Answer 11

Fe - vit C

Question 12

what happens if don’t convert lysine to hydroxylisine (lacking Vit. C)

Answer 12

Ehlers Daniels Type 6

- super extensible skin, joint laxity, detached lenses

Question 13

what happens if fail to remove N-registration peptide

Answer 13

Ehlers Daniels Type 7

• interferes with collagen fiber packing
• skin brittle, congenital dislocations

Question 14

what happens if fail to form lysine/hydroxylisine cross-link

Answer 14

cutis laxa - decreased crosslinking - loose floppy skin - sharpei

Question 15

causes of fail to form lysine/hydroxylisine cross-link

Answer 15

defects in copper metbolism

Question 16

2 major types of genetic collagen

Answer 16

1. continuous - types 1,2,3

2. discontinuous - types 4

Question 17

locations of Type 1 collagen

Answer 17

skin, bone, tendon, ligament

Question 18

locations of Type 2 collagen

Answer 18

cartilage, cornea,

Question 19

locations of Type 3 collagen

Answer 19

fetal skin, vasuclar tissues

Question 20

locations of Type 4 collagen

Answer 20

basement membrane

Question 21

feature of discontinuous collagen

Answer 21

registration peptide not removed

Question 22

cause of chondroplasias

Answer 22

mutations in type 2,9,10,11

Question 23

consequences of chondroplasia

Answer 23

malformations in articular cart
joint deformities
familial osteoartritis

Question 24

what happens for mutations in type 3 coll.

Answer 24

EDS type 4 - most severe phenotype

• thin translucent skin
• fragile blood vessels

Question 25

what happens for mutations in type 4 coll.

Answer 25

Alport syndrome - def. in basement membrane

• glomerulnephritis, kidney failure
• hearing loss

Question 26

what happens for mutations in type 7 coll.

Answer 26

dystrophic epidermolysis

• failure of demis to anchor
• severe blistering of skin to minor trauma

Question 27

what happens for mutations in type 1 coll.

Answer 27

osteogenisis imperfecta

- bone fragility, blue sclera, hearing loss

Question 28

cause of osteogenisis imperfecta (2)

Answer 28

1. silent allele causes deletion so one of the 3 triple helix strands to not form
2. point mutation - Gly to Cys - kinks triple chain

Question 29

chances of mutation in osteogenisis imperfecta based on allele?

Answer 29

a2 - 1/2 messed up (choose once)

a1 - 3/4 messed up (choose twice)

Question 30

Important chars. of elastin

Answer 30

• single gene
• don’t lay more down
• mechanical durability

Question 31

changes in dist. of elastin vs. collagen

Answer 31

as go from aortic arch down becomes less elastic

Question 32

what is structure of tropoelastin

Answer 32

alternating hydrophobic and crosslinking domains

Question 33

3 basic layers of aorta

Answer 33

1. intimal
2. medial
3. adventitial

Question 34

what part unravels when elastin pulled

Answer 34

hydrophobic domains - refold in polar H2O

Question 35

consequences of supravalvular aortic stenosis

Answer 35

• narrowing of arterial vessels

Question 36

cause of supravalvular aortic stenosis

Answer 36

• frameshift mutations, translocations - one allele doesn’t function
• 1/2 the elastin
• gene/dose effect

Question 37

consequences of williams-beuren

Answer 37

• SVAS is common

- cocktail personality

Question 38

causes of williams-beuren

Answer 38

• large deletion of chrom 7

Question 39

consequences of cutis laxa

Answer 39

• loose saggy skin

Question 40

causes of cutis laxa

Answer 40

• frameshift mutation near c-term

- disordered, fragmented elastics

Question 41

probs from hypertension

Answer 41

• vessel deposits extra elastin due to pressure which fills in vessel

Question 42

causes of arteriosclerosis

Answer 42

1. elastic lamina fragments
2. smooth muscle migrated to intimal layer
3. thickening of intimal layer causes plaque

Question 43

causes of emphysema

Answer 43

breakdown of elastin in alveoli

Question 44

what does elastin form on

Answer 44

scafolding of microfibrils

Question 45

causes of marfans

Answer 45

defects in fibrillin-1 > can’t make microfibrils

Question 46

features of proteoglycans

Answer 46

• viscous
• resist compression
• regulate macromolecule diffusion
• bind and trap cations

Question 47

basic structure of proteoglycans

Answer 47

protein core with attached glycosaminoglycan

- form bottlebrush shape of core of hyaluronic acid

Question 48

causes of lysosomal storage diseases

Answer 48

• don’t have enzymes to break down proteoglycans

- they build up in lysosomes

Question 49

cause of hurler’s syndrome

Answer 49

• don’t have specific enzyme (iduronidase)

Question 50

consequences of hurler’s

Answer 50

• accumulate heparin sulfates
• progressive cell, tissue, organ damage
• corneal clouding
• severe mental retardation

Question 51

function of fibronectin and laminin (3)

Answer 51

1. link matrix to matrix and cells
2. organize matrix
3. outside-in signalling