________________ receptors convert chemical into electrical signals.
What is the conversion of one type of signal into another?
What are four types of cell signaling?
Endocrine, Paracrine, Neuronal, and Contact-dependent
__________________ signaling controls nerve-cell production.
True or false: The same signal molecule can induce different responses in different target cells.
Extracellular signals alter the activity of diverse cell _________ to alter cellular behavior.
Extracellular signal molecules can bind to ______________ receptors or _____________ receptors and enzymes.
Nitric oxide (NO) triggers smooth muscle _____________ in a blood-vessel wall.
Steroid hormones bind intracellular receptors that act as _________________________ proteins.
True or false: Gases such as NO are the only signal molecules that can cross the plasma membrane.
The steroid hormone __________ acts by activating a gene regulatory protein.
What are the three basic classes of cell surface receptors?
G-protein-linked, Ion-channel-linked, and Enzyme-linked
Many intracellular signaling proteins act as ___________________.
True or false: All G-protein-linked receptors possess a similar structure.
When activated, G-proteins....?
dissociate into two signaling proteins
The G protein alpha-subunit switches itself off by _______________________.
hydrolyzing bound GTP
G proteins couple receptor activation to opening of _______________ K+ channels.
What catalyzes the synthesis of intracellular second-messengers?
Enzymes activated by G-proteins
Cyclic AMP is synthesized by ____________, and degraded by __________________
adenyl cyclase; cyclic AMP phosphodiesterase
Cyclic AMP concentration rises rapidly in response to which extracellular signal?
Receptor tyrosine kinases activate the GTP-binding protein _____.
_______________ networks integrate information to control complex cell behaviors.
Activation of a _______________________ directs assembly of an intracellular complex.
receptor tyrosine kinase
True or false: The Ras protein is monomeric and a membrane-linked GTPase.
__________ percent of human cancers come from activating mutations in ras genes.
________________ activates a MAP-kinase phosphorylation cascade
What receptors are associated with cytoplasmic tyrosine kinases?
TGF-beta/BMP receptors activate ___________________ directly at the plasma membrane.
gene regulatory proteins