Signal Transduction and Cell Communication

Question 1

What is the Cell Theory?

Answer 1

Living organisms are composed of cells
The Cell is the basic functional unit of life
All cells arise only from other pre-existing cells

Question 2

What do gap junctions allow?

Answer 2

small molecules can pass readily between cells that are connected by gap junctions w/o crossing plasma membranes

Question 3

What are indirect types of signaling?

Answer 3

autocrine- sending and receiving cells are the same
paracrine- receiving cell is near the sender
hormonal- hormones released by endocrine cells through the circulatory system
synaptic: electrical signals stimulate the release of a neurotransmitter

Question 4

What are the three major types of transmembrane receptors?

Answer 4

G-protein coupled receptors (GPCRs)
RTK
Ligand-gated ion channels

Question 5

Characteristics of GPCRs

Answer 5

Very common
receptor has seven transmembrane helices
have three subunits: alpha, beta, and gamma
Termination: initially GTP hydrolysis, later GRK/arrestins