Chapter 6.4: Signal Transduction Is Highly Regulated

Flashcards from Chapter 6.4 of Principles of Life, 3rd Edition.

Signal termination

The end of signal transduction where pathways are reset and allow the cell to respond again

• Can be done through receptor recycling, chemical reversion, or molecule loss

• Can also be effected through enzyme activation or synthesis states

Receptor recycling

One of three methods of signal termination where membrane receptors are endocytosed and degraded in lysosomes

Chemical reversion

One of three methods of signal termination where molecules are converted back to inactive states

• Seen with G proteins removing their phosphate group, leading to their inactivation and alpha subunit unbinding

Signal molecule loss

One of three methods of signal termination where molecules diffuse out of the cell, shutting down a response

Glucagon

A hormone produced by the pancreas that activates adenylyl cyclase in the epinephrine pathway for an equivalent response, increasing blood glucose levels

Insulin

A hormone that activates phosphodiesterase to reduce glycogen phosphorylation and increases glucose carrier proteins for rapid uptake from the blood

• Counteracts glucagon and epinephrine, a conflict that can be hard to model