Lecture 11

Question 1

Know the four essential elements of cell communication

Answer 1

1. signaling cell
2. signaling molecule
3. receptor molecule
4. receptor cell

Question 2

Know and describe the four steps in cell signaling

Answer 2

1. receptor activation: the signal binds to a receptor, which is then activated
2. signal transduction: the signal is transmitted to the interior of the cell by a signal transduction pathway
3. response: the responds, for example, by activating an enzyme or turning on transcription of a gene
4. termination: the response is terminated so that new signals can be received

Question 3

Know, describe and compare the four classes of cell signaling

Answer 3

endocrine:
paracrine:
autocrine:
juxtacrine:

Question 4

Know and describe the interaction between a signaling molecule (ligand) and its receptor

Answer 4

Binding of a ligand to its’ binding site on a receptor causes a conformational change in the receptor that triggers chemical reactions

Question 5

Know, describe and compare polar molecules and cell-surface receptors to nonpolar molecules and intracellular receptors

Answer 5

polar signaling: cannot cross the plasma membrane and rely on cell-surface receptors
nonpolar signaling: molecules can freely pass through the plasma membrane and activate cytoplasmic receptors