ADD Cell junctions

Question 1

What are the different types of cell junctions?

Answer 1

-tight junction
-cell cell anchoring junctions
-channel forming junctions
-cell matrix anchoring junctions

Question 2

What are adherens junctions also known as and what are they made up of?

Answer 2

-AKA belt desmosomes
-made up of cadherins

Question 3

What is cadherin and what can it do?

Answer 3

-it’s a Ca2+ dependent adherin molecule
-makes homophilic interactions
-makes strong links between cells
-links to actin cytoskeleton

Question 4

What happens when the adhesion belt contracts?

Answer 4

-bottom of epithelial cells doesn’t, causing sheet of cells to bend
-tube pinches off - forms hollow, cylindrical tube

Question 5

What junctions link to the actin cytoskeleton?

Answer 5

-focal adhesions
-adherens junctions

Question 6

What do hemidesmosomes do?

Answer 6

Attach cells to basal lamina

Question 7

What do desmosomes do and where are they mainly found?

Answer 7

-form cell to cell junctions
-found in heart muscle + epidermis

Question 8

What do gap junctions do?

Answer 8

Allow regulated + directed cell-cell communication

Question 9

What is the structure of gap junctions?

Answer 9

-made of connexins
-connexins can be made up of 1 type of connexin (homomeric) or multiple (connexons)
-so can have many types of channel

Question 10

What are gap junctions regulated by?

Answer 10

-membrane potential, pH, Ca2+ and cell signals
-limit damage caused by Ca2+