cell adhesion and extracellular matrix

Question 1

what do we find in extracellular matrix?

Answer 1

fibrillar proteins and polysaccharide glyogosaminoglycans (GAGs)-organised into proteoglycans

Question 2

cells in connective tissue

Answer 2

chondrocytes
osteoblasts
fibroblasts
myofibroblasts
blood cells
adipocytes

Question 3

Fibrillar proteins

Answer 3

collagen
elastin
fibronectin
laminin

Question 4

What is special about collagen?

Answer 4

packed into large vescicles in RER
Secreted by exocytosis in a membrane tube called fibriposter to make a fibril
fibril organised into fibres by other cells

Question 5

what synthesises elastin?

Answer 5

fibroblasts
smooth muscle cells
chondroblasts

Question 6

what do proteoglycans do?

what is their charge?

Answer 6

matrix support/cushioning and hydration
glue like function
links between proteins of ECM and ECM and cell surface

Question 7

What are GAGs and what is their charge?

Answer 7

Chains of repeating disaccharide units

Highly negatively charged

Question 8

How does the ECM bind to cytoskeleton?

Answer 8

Colleagen and proteoglycan bind to fibronectin which binds o integrin which binds to adaptor protein then actin cytoskeleton

Question 9

What are the two functions of myofibroblasts?

Answer 9

Secrete collagen and asct as smooth muscle cells (synthesise actin, myosin, desmin)

Question 10

4 functions of myofibroblasts in tissue damage

Answer 10

proliferate
secrete collagen
consolidate damaged area
contract

Question 11

Functions of adipocytes

Answer 11

energy storage
packing (eye)
insulation

Question 12

Obob genes mean that

Answer 12

You become resistant to leptin

Question 13

function of cell junctions and adhesion proteins

Answer 13

link cells and their cytoskeletons to:
other cells
ECM

Question 14

List 4 cell junctions

Answer 14

tight junctions
adherens
desmosome(filaments, plaque, cadherins)
gap junction

Question 15

cell to cell adhesion done by

Answer 15

integrin, selectin, CAM

Question 16

Cell to ECM

Answer 16

focal adhesion(integrins, signalling platforms)
hemi-desmosome(more stable, intermediate filaments, laminin in BM)
integrin
membrane proteoglycan

Question 17

What do tight junctions do

Answer 17

Define polarity
Allow passage of substances between cells
Determine permeability (different claudins)
can link actin to cytoskeleton

Question 18

Gap junctions

Answer 18

look like flowers
communication
hydrophobic channels, small molecules
coordination of function

Question 19

CAUSE Duchenne’s muscular dystrophy

Answer 19

Absence of adaptor for integrin to intracellular compartment due to gene mutation(premature termination of translation)

Question 20

CONSEQUENCE dmd

Answer 20

Damage to muscle fibre due to muscle tearing

muscle wasting and weakness - unable to walk by 12

Question 21

What drug is used to combat DMD and how does it work?

Answer 21

PTC 124, ataluren

Overrides premature stop signal mutation to produce normal dystrophin

Question 22

Role of cell adhesions and interactions with ECM during cancer stages

Answer 22

tumour cells accumulate, cadherins reduced and invasion of BM. Integrins promote interaction with ECM and non epithelial cells