Unit 1 Extracellular matrix

Question 1

ECM function

Answer 1

reservoir, strength, shape, exchange

Question 2

ECM components

Answer 2

structural proteins
protein-polysaccharide complexes
adhesive glycoproteins

Question 3

ground substance

Answer 3

highly hydrated, transparent, complex mixture of macromolecules

Question 4

glycosaminoglycans

Answer 4

GAGS aka mucoplysaccharies
1. linear polysaccharides formed of repeating disaccharides [uronic acid (glucuronic, idruonic acid)
hexosamine (glucosamine, galactosamine)]
2. covalently linked to core protein to form proteoglycan
3. abundant sulfate and carboxyl groups make molecules hydrophilic, negatively charged

Question 5

examples of GAGs

Answer 5

dermatan sulfate
chondroitin sulfate
keratan sulfate
heparin sulfate

Question 6

GAG exception

Answer 6

hyaluronic acid not linked to protein

Question 7

proteoglycan

Answer 7

core protein + GAGs

Question 8

collagen

Answer 8

name of protein and fiber
family of 25+ proteins
synthesis as procollagen; soluble; triple helix of 3 polypeptiees
converted to tropocollagen (insoluble)
self-assembles to fibrils and fibers

Question 9

type I collagen

Answer 9

ubiquitous; largest fibers

Question 10

type II collagen

Answer 10

hyaline/elastic; fibrils only

Question 11

type III collagen

Answer 11

reticular

Question 12

type IV collagen

Answer 12

no fibers, meshwork, basal lamina

Question 13

fibroblast

Answer 13

secretes collagen in connective tissues

Question 14

reticular

Answer 14

thin, loose network
argyrophilic (silver affinity)
lymphoid glands

Question 15

elastic

Answer 15

composed of elastin

cross-linked peptides provide extensibility

Question 16

adhesive glycoproteins

Answer 16

fibronectin

laminin

Question 17

fibronectin

Answer 17

binds cells to comments of ECM; embryonic cell migration
subunit folded into domains
domains bind to ECM macromolecules
bind cell surface receptors via RGD
many cancer cells don’t produce fibronectin

Question 18

laminin

Answer 18

synthesized by epithelial cells
binds epithelia to components of basal lamina
binding sites

Question 19

integrins

Answer 19

family of cell surface receptors that bind to fibronectins, laminins, collagen
integrate cytoskeleton with ECM
regulate cell movt & attachment

Question 20

basal lamina

Answer 20

structural support
permeability barrier
attaches epithelia to CT
type IV, laminin