Lecture 10

Question 1

What are the three kinds of Cell unctions?

Answer 1

The three general kinds of cell junctions and their nature and function: tight, anchoring (adherens, desmosomes, hemidesmosomes) and communicating

Question 2

Tight Junctions

Answer 2

TIGHT TOGETHER!!!

AKA occluding junctions or zonulae occludentes (singular, zonula occludens), are the closely associated areas of two cells whose membranes join together forming a virtually impermeable barrier to fluid. Only in vertebrates.

Question 3

Anchoring Junctions

Answer 3

Anchor cells within tissues and organs to one another.

(Junction–Cytoskeletal Anchor–Transmembrane Linker–Ties Cell To:)
Desmosomes–Intermediate filaments–Cadherin–Other Cells.
Hemidesmosomes–Intermediate Filaments–Integrins–EC Matrix
Adherens junctions–Actin Filaments–Cadherin/Integrins–Other Cells / the EC Matrix

Question 4

Communicating (GAP) Junctions

Answer 4

Allow for direct chemical communication between adjacent cellular cytoplasm through diffusion without contact of the extracellular fluid.

Question 5

Integrins

Answer 5

transmembrane linker protein. Communicates with extracellular matrix molecules.

Question 6

Cadherins

Answer 6

Cell adhesion Molecule. Ca++-dependent found in all vertebrates. There are also Ca++ independent ones.

Basically binds to a bunch of different things, intra and extracellularly.

Question 7

Selectins

Answer 7

Ca++-dependent. Link to white blood cells, carry to inflammation sites.

Question 8

N-CAM

Answer 8

Neural Cell Adhesion Molecule. Ca++-INdependent. Involved in cell to cell adhesion through homophilic reactions