Interactions between cells and their environments: Part 1 Flashcards Preview

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Flashcards in Interactions between cells and their environments: Part 1 Deck (45):
1

Cells are organized into _______

tissues

2

What gets transmitted from cell to cell by cytoskeletal filaments?

mechanical stresses

3

What makes up epithelial tissues?

lines, cavities, organs and surfaces

4

What are examples of connective tissues?

bones, tendons

5

Compare epithelial tissues and connective tissues based on cell association, the amount of ECM, what provides resistance to mechanical stress, and what cells are attached to.

Epithelial tissues: cells closely associated; limited ECM; cytoskeletal filaments provide resistance to mechanical stress; cells are attached to each other

Connective tissues: cells rarely connected; lots of ECM; ECM provides resistance to mechanical stress; cells attached to the matrix

6

What is the basal lamina?

thin layer of ECM

7

What are four types of junctions? Which ones are present in epithelial cells?

1. anchoring junctions
2. channel-forming junctions
3. occluding junctions
4. signal-relaying junctions

8

What is another name for occluding junctions? What are two functions

tight junctions
1. creates a tight seal between cells to prevent mixing of the extracellular environment
2. act as fences in the membrane to prevent mixing of membrane proteins (apical and basal)

9

______ and ______ proteins form the seal.

claudin and occludin

10

What interacts with extracellular domains of the proteins in one cell?

extracellular domains of the neighbouring cell

11

Claudin is required for...

tight junction seals

12

What is a sealing strand?

many tight junctions

13

Plasma membranes of ______ cells are brought closer together at the sealing strand

adjacent

14

Tight junctions are dependent on ______ junctions.

adherens

15

What happens if you block the formation of adherens junctions?

tight junctions don't form properly

16

What three junctions make up the junctional complex

tight junctions, adherens junctions, desmosomal junctions

17

Where are anchoring junctions located?

cell-cell
cell-matrix

18

Anchoring junctions link the ______ of neighbouring cells.

cytoskeletons

19

What do adhesion and anchor proteins link together?

cytoskeletons of neighbouring cells

20

What two things do adhesion proteins interact with?

1. neighbour adhesion proteins
2. anchor proteins

21

What is an example of adhesion proteins?

cadherens

22

What links the adhesion proteins to cytoskeletal filaments? (cytosolic proteins)

anchor proteins

23

What does the adhesion belt encircle?

the inside of the PM

24

What kind of proteins are adhesion and anchor proteins? (location)

adhesion: transmembrane proteins
anchor: cytosolic proteins

25

What is tethered to cadherin by anchor proteins

actin

26

What two things link intermediate filaments?

desmosomes and hemidesmosomes

27

What is the function of intermediate filaments?

provide structural support

28

What does a desmosome link to?
What does a hemidesmosome link to?

neighbouring cell
basal lamina

29

What are two specific cadherin family adhesion proteins?

desmoglein and desmocollin

30

Hemidesmosomes link to _____ filaments inside the cell and link to _____ in the ECM

keratin
laminin

31

What is integrin?

a transmembrane protein in hemidesmosome; links anchoring proteins to laminin

32

Where is laminin located?

basal lamina

33

Hemidesmosomes anchor _______ _______ in a cell to the ECM

intermediate filaments

34

What is the role of gap junctions? What are they composed of?

provide communication between cells; composed of connexin proteins

35

1 connexin = 4 ?
6 connexins = 1 ?

4 transmembrane proteins
1 connexon

36

2 connexons = 1 ?

gap junction

37

What is another term for connexon?

hemichannel

38

Different connexin proteins can be present in the same ______

channel

39

What are two types of connexons? What are two types of intercellular channels?

homomeric, heteromeric
homotypic, heterotypic

40

Gap junctions allow the passage of ______ and ______.

ions and metabolites

41

Are gap junctions gated?

yes; can be in open or closed state

42

Is one connexon on its own usually open or closed?

closed

43

A dramatic increase in _____ _____ will close jap junctions.

cytosolic Ca2+

44

Is cytosolic calcium usually low or high?

low

45

What happens when the membrane is damaged?

-calcium leaks into cell while metabolites leak out
-gap junctions close in response to high calcium to prevent losing metabolites from adjacent cells