Unit 1 Cell Junctions

Question 1

cell junctions

Answer 1

specialized attachments between adjacent cells
modifications of plasma membrane
cytoplasmic continuity between cells

Question 2

tight junctions

Answer 2

aka zonula occludens
prevent water soluble molecules from passing through ECM between cells
fuse adjacent plasma membranes
maintains polarity
disrupted by reduction of calcium

Question 3

tight junction proteins

Answer 3

claudins

occludens

Question 4

adherents junctions

Answer 4

zonula adherens
desmosomes
hemidesmosomes

Question 5

zonula adherens

Answer 5

calcium dependent cadherin of adjacent cells bind to adhere cells to each other
actin microfilaments in cell anchor cadheren transmembrane glycoproteins of each cell (calcium dependent)

Question 6

desmosomes

Answer 6

aka macula adherens; disc shaped; similar to zonula adherens

cytoplasmic intermediate filaments anchor cadherin

Question 7

hemidesmosomes

Answer 7

attach cell to components of ECM

Question 8

gap junctions

Answer 8

communicating junctions; allows passage of ions and small molecules between adjacent cells
cells connected by connexions (6 subunits composed of protein connexins)
cardiac/smooth muscle

Question 9

terminal bar

Answer 9

groups of junctional complexes that attach adjacent epithelial cells on their lateral surfaces

Question 10

surface specialization

Answer 10

to increase surface area, move substances across surface
microvilli
stereocilia
cilia

Question 11

microvilli

Answer 11

covered with glycocalyx
form brush border
found extensively on apical surfaces of absorptive cells
core of actin filaments arranged longitudinally
not motile

Question 12

stereocilia

Answer 12

long branched microvilli; increase surface area for transport across membrane

Question 13

cilia & flagella

Answer 13

motile; aka axoneme

motor protein is axonemal dynein