Chapter 19

Question 1

What are the two ways cells can communicate with each other

Answer 1

Directly or through the extracellular matrix

Question 2

Network of proteins and polysaccharides that are secreted by the cell; directly bears mechanical stresses of tension and compression

Answer 2

Extracellular matrix

Question 3

This junction allows neighboring cells to adhere together

Answer 3

Anchoring junctions

Question 4

Seals gap between epithelial cells

Answer 4

Tight junction

Question 5

Connects intermediate filaments in one cell to those in the next cell; provides mechanical strength; involves non classical cadherin proteins

Answer 5

Desmosome

Question 6

Connects actin filament bundle in one cell with that in the next cell

Answer 6

Adherens junction

Question 7

Anchors intermediate filament into cell to extracellular matrix

Answer 7

Hemidesmosome

Question 8

Anchors actin filaments in cell to extracellular matrix

Answer 8

Actin linked cell matrix junction

Question 9

Does not allow any passage of molecules between cell spaces; form barriers; usually formed between cells at the upper lateral surface

Answer 9

Tight junctions

Question 10

Allow passage of molecules between neighboring cells

Answer 10

Gap junctions

Question 11

These proteins are found in adherins and desmosome junctions( the anchoring junctions)

Answer 11

Cadherins

Question 12

These proteins are found in hemidesmosomes and actin- linked cell matrix junction ( anchoring junctions)

Answer 12

Integrins

Question 13

What are two types of cadherins

Answer 13

Classical

Non classical

Question 14

What do cadherins need to perform the adhering function

Answer 14

Ca2+

Question 15

Cadherins have _______ adhesion

Answer 15

Homophilic

They bind to cadherins if same or closely related subtype

Question 16

What ions bind to hinge regions of cadherin domains; if these are absent what happens to cadherin structure

Answer 16

Ca2+

Collapses

Question 17

These are adaptor proteins that aid in linking cadherins to actin filaments in adherens junction

Answer 17

Catenins

Question 18

This binds when the alpha catenin has a conformational change due from tension

Answer 18

Vinculin bind to actin filaments and strengthens junction

Question 19

This is composed of a long row of transmembrane homophilic adhesion proteins

Answer 19

Tight junction

Question 20

What proteins are involved with tight junctions

Answer 20

Claudin

Occludin

Question 21

What adaptor proteins are involved with tight junctions

Answer 21

Zona occludin

Question 22

Multi domain proteins that allow many proteins to bind to generate the tight junction

Answer 22

Zona occludens

Question 23

Allow transport of small water soluble molecules between neighboring cells

Answer 23

Gap junctions

Question 24

What channel forming proteins compose the gap junctions

Answer 24

Connexins ( vertebrae)

Innexins ( invertebrates)

Question 25

6 connexins polymerize to form

Answer 25

Hemi channel - connexon

Question 26

Same connexins that form a comnexon

Answer 26

Homomeric

Question 27

Different connexins that form a connexon

Answer 27

Heteromeric

Question 28

Connexons that are homomeric and form a channel

Answer 28

Homotypic

Question 29

For the connexons to have a homotypic and hetertypic channels what is significant about this characteristic

Answer 29

Allows for transport of variety of molecules

Question 30

What are some cells that secrete ECM

Answer 30

Fibroblasts in connective tissues

Question 31

These are highly charged polysaccharides that have a repeating disaccharide

Answer 31

GAGs

Question 32

Aid I. Organizing the matrix and help in attaching cells to the matrix

Answer 32

Glycoproteins

Fibronectin

Question 33

This protein is a dimer that are joined at c terminus with disulfide bonds ; can bind to collagen , integrins

Answer 33

Fibronectins

Question 34

What is the degradation of the ECM mediated by

Answer 34

Matrix metallopeoteases > depend on Ca Zn for activity

Serine proteases

Question 35

What links ECM to the cytoskeleton

Answer 35

Integrins