cell communication

Question 1

connexins, simplest form of cell communicaiton,

Answer 1

The simplest form of cell-to-cell communication is the direct transfer of electrical and chemical signals through gap junctions
A gap junction forms from the union of membrane-spanning proteins called connexins between adjacent cells.
Create a protein channel, or connexon, that can open and close
Ubiquitous, but found particularly in heart and smooth muscle.

Question 2

contact dependent signals

Answer 2

. Contact-Dependent Signals require that surface molecules on one cell membrane bind to a membrane protein of another cell.
Cell adhesion molecules (CAMs) act as receptors in cell-to-cell signaling.
CAMs are linked to cytoskeleton and to intracellular enzymes.
Bidirectional communication possible
Contact-dependent signaling occurs in the immune system and during growth and development

Question 3

local diffusion

Answer 3

. Local Diffusion allows movement of molecules through short distances.
Autocrine Signal – chemical signal acts on the same cell that secreted it
Paracrine Signal – chemical acts on cells in the immediate vicinity