lecture 7

Question 1

what are the cell surface receptors

Answer 1

fibronectin
laminin
proteoglycans
collagen
integrins

Question 2

where are integrins found

Answer 2

in animal cells
surface of all vertebrate cell types

Question 3

what do interns interact with

Answer 3

outside proteins

Question 4

what the structure of integrins

Answer 4

2 membrane spanning polypeptide chains
alpha and beta

Question 5

what does heterodimer mean

Answer 5

different subunits

Question 6

when integrins are in the bent form, what is there activity

Answer 6

inactive

Question 7

when integrins are in the active form, what is their shape

Answer 7

straight

Question 8

what are integrins

Answer 8

glycoproteins

Question 9

what do integrins do

Answer 9

link matrix outside a cell to the cytoskeleton inside it

Question 10

what are the 2 main functions of integrins

Answer 10

cell adhesion
signal transduction

Question 11

what links intern to the actin filaments

Answer 11

adapter proteins

Question 12

what does kindlin to

Answer 12

helps with inside out signalling of integrins

Question 13

what is talin

Answer 13

helps with outside in signalling of integrins

Question 14

what are malignant cells

Answer 14

cells that can grow in suspension and dont require integrins
they are integrin independent

Question 15

what do normal cells require for growth

Answer 15

they require integrin binding and will die in suspension

Question 16

what is recognized by integrin for binding

Answer 16

the RGD (arginine - glycine - aspartic acid) amino acid sequence

Question 17

what do integrins do in platelet aggregation

Answer 17

allow the platelets to bind by recognizing the fibrinogen within the blood

Question 18

where are cell to cell junctions found

Answer 18

in cells that dont move (immobile cells)

Question 19

what are cell - cell junctions

Answer 19

protein structure that physically connect cells

Question 20

where are epithelial cells found

Answer 20

basically anywhere that faces the external world
they rest on the basal lamina

Question 21

how are epithelial sheets/cell junctions names based on shape

Answer 21

named on the outer most layer (the layer closest to the basal lamina)

Question 22

what makes up the basement membrane

Answer 22

type 4 collagen
laminin

Question 23

are epethelial cells polarized

Answer 23

yes

Question 24

what do tight junctions do

Answer 24

seal gaps between epithelial cell membranes to not let ECM into the intracellular matrix

they prevent passage of H2O/bacteria

Question 25

what do adherens junction do

Answer 25

connects actin filament bundle in one cell with that in another cell

Question 26

what do desmosomes do

Answer 26

connects intermediate filaments in one cell to another

Question 27

what do gap junctions do

Answer 27

allows the passage of small water soluble molecules from cell to cell

Question 28

what do hemidesmosomes do

Answer 28

anchors intermediate filaments in a cell to extracellular matrix/ basement membrane

Question 29

what are keratin filaments specific to

Answer 29

epithelial cells

Question 30

what links integrins to basement membrane in regards to hesmidesmosomes

Answer 30

laminin

Question 31

what links the intracellular part to the integrins within hemidesmosomes

Answer 31

keratin

Question 32

what side of the membrane are tight junctions on

Answer 32

apical

Question 33

what prevents the passage of H2O from ECM

Answer 33

tight junctions

Question 34

what are the major transmembrane proteins in tight junctions

Answer 34

Claudins Occludins

Question 35

what kind of family are cadherins a part of

Answer 35

glycoproteins

Question 36

do cadherins join cells of similar cell type ?

Answer 36

yes

Question 37

whats the most important factor in molding cells into cohesive tissues in the embryo and holding them together in the adult

Answer 37

cadherins

Question 38

what is cadherin loss associated with

Answer 38

malignancy

Question 39

what protein do desmosomes and adherens junctions have in them

Answer 39

cadherins

Question 40

what provides cells with tensile strength

Answer 40

cadherin

Question 41

what are adherens junction linked by

Answer 41

actin cytoskeleton

Question 42

structure of adherens junctions

Answer 42

1. actin filaments - provide shape 2. protein plaques - anchor membrane and bind to actin 3. cadherins - attach to protein plaques and connect to cadherins on other cells

Question 43

what forms adhesion belts

Answer 43

adherens junctions

Question 44

what are the specialized cadherins within desmosome junctions

Answer 44

desmoglein desmocollin

Question 44

what do desmoglein and desmocollin bind to?

Answer 44

intermediate filaments (keratin) on the cytoplasmic side

Question 46

what causes strong cell adhesion on the epidermis of skin

Answer 46

desmosomes

Question 47

what does lacking desmoglein cause

Answer 47

pemphigus vulgaris (major blistering)

Question 48

what do gap junctions connect ? what do they connect by

Answer 48

they connect adjacent cells by the cytosol

Question 49

how are gap junctions connected (protein and coupling)

Answer 49

connexin electrically

Question 50

what is connexin

Answer 50

an integral membrane protein 4 transmembrane domains that create a pore plays an important role in gap junctions