Lecture 14

Question 1

Epithelial, muscle, and nervous tissue cells characteristics

Answer 1

• little ECM
• intermediate filaments and cell-cell junctions provide strength

Question 2

Connective tissue characteristics

Answer 2

• few cells
• have lots of extracellular matrix (ECM) that provides strength

Question 3

Epithelial cells are organized into ___

Answer 3

sheets

Question 4

the (epithelial) sheets can be rolled up into ____

Answer 4

tubes

Question 5

tight junction

Answer 5

seals neighbouring cells together

Question 6

adherens junction

Answer 6

joins actin bundle in one cell to a similar bundle in neighbouring cell

Question 7

desmosome

Answer 7

joins intermediate filaments in one cell to those in a neighbour

Question 8

gap junction

Answer 8

forms channels that allow small, intracellular, water-soluble molecs - including inorganic ions and metabolites to pass from cell to cell

Question 9

hemidesmosome

Answer 9

anchors intermediate filaments in a cell to the basal lamina

Question 10

plants only have ________ equivalent: plasmo_____

Answer 10

gap junction
desmata

Question 11

Plasma membrane proteins anchor to what?

Answer 11

to cytoskeletal on the inside

Question 12

Tight junctions form seals between cells which does what?

Answer 12

stops diffusion across the epithelial sheet

Question 13

tight junctions allow ____ in the plasma membrane to diffue freely but NOT ______

Answer 13

lipids
membrane proteins

Question 14

Epithelia are ________

Answer 14

functionally polarized

Question 15

Tight junctions allow the ____ and _____ membranes to be different in function and composition

Answer 15

apical
basolateral

Question 16

transcytosis

Answer 16

polarized transport of proteins from one side of the epithelium to the other

Question 17

aherens junctions and desmosomes both use what to link the cytoskeleton of epithelial cells to their neighbours?

Answer 17

cadherins

Question 18

hemidesmosomes link the cytoskeleton of epithelial cells to the _______ using ________

Answer 18

basal lamina
integrins

Question 19

cadherin family

Answer 19

• transmembrane proteins - in the plasma membrane
• bind to an identical cadherin in the next cell

Question 20

transmembrane proteins binding to identical cadherin in the next cell - interaction needs _____

Answer 20

calcium (Ca2+)

Question 21

in adherens junctions, cadherins link to ______

Answer 21

actin filamets

Question 22

adhesion belt

Answer 22

continuous band of adherens junctions

Question 23

what link the cytoskeleton of epithelial cells to their neighbours? (and both use what?)

Answer 23

adherens junctions and desmosomes
they use cadherins

Question 24

Desmosomes do what?

Answer 24

link intermediate filaments in each cell together across the epithelium

Question 25

IFs provide protection against _____

Answer 25

stretching (epithelial and muscle cells)

Question 26

desmosomes are abundant in what kind of tissue?

Answer 26

tissues under high shear stress - i.e. heart muscle

Question 27

Desmosomes in adjacent muscle cells are linked to ______________

Answer 27

desmin intermediate filaments

Question 28

Desmin is expressed in: (3)

Answer 28

• cardiac muscle
• skeletal muscle
• smooth mucle

Question 29

desmin mutations cause: (2)

Answer 29

• muscular dystrophy
• cardiac myopathy

Question 30

integrins in basal plasma membrane bind to:

Answer 30

laminin in the basal lamina

Question 31

What difference are the membrane proteins in hemi-desmosomes and desmosomes?

Answer 31

integrins in hemi-desmosomes
cadherins in desmosomes

Question 32

integrins in focal adhesions link to ________

Answer 32

actin filaments

Question 33

integrin in hemi-desmosomes link to _________

Answer 33

keratin IFs

Question 34

Epithelial cells express ______

Answer 34

E-cadherin

Question 35

Muscle cells express ________

Answer 35

N-cadherin

Question 36

What is the relation between cancer cells and cadherin expression?

Answer 36

cancer cells often no longer express the speciifc cadherins that would normally keep a cell in its correct place

Question 37

85% of cancers start in ________ (And what are they called?)

Answer 37

epithelial tissues - these are carcinomas

Question 38

Connexon channels allow ________ of inorganic ____ and small ___________

Answer 38

direct transfer
ions
water-soluble molecules (<1000 daltons)

Question 39

Plasmodesmata

Answer 39

the plant equivalent of gap junctions

Question 40

Large molecules can pass through _______ such as ___ and regulatory ____

Answer 40

plasmodesmata
proteins
mRNAs