Bio 1A Ch 9
The process through which cells can detect and respond to signals in their extracellular environment is _______
Cell communication
What do synaptic signaling and paracrine signaling have in common?
Cells release a signal that affect neighboring cells
A key is placed into a keyhole then turned and the door opens. When considering the components of cell signaling, the action of turning the key would best correspond to
Conformational change in the receptor once bound to the hormone
When sodium ions move from one cardiac muscle cell to an adjacent cell causing them to contract in unison this is an example of _______
Direct intercellular signaling
A G-protein coupled receptor associated with a G protein that contains how many subunits?
3
When epinephrine binds to its G-protein linked receptor ______ is activated producing ______
Adenylyl cyclase, cAMP
During exposure to elevated glucose, a yeast cell will increase its uptake of glucose. Describe the mechanism by which the yeast sense the extracellular glucose.
By glucose binding to glucose receptors.
When the concentration of a ligand is equal to the Kd which of the following is true?
Half of the receptors are bound to ligands
When a neurotransmitter released from one neuron binds to a _____ on a second neuron, that neuron depolarizes and fires.
Ligand-gated ion channel
If the concentration of a ligand is 100 times greater than the Kd of its receptor, ______ of the receptors will be bound to a ligand.
Most
When insulin binds to it's G-protein coupled receptor (GPCR) what happens next?
The G protein loses GDP and gains GTP becoming activated.
Following its initial activation, how does a G protein become inactivated?
The G-protein a subunit GTP is hydrolyzed to GDP allowing reassociation of the G-protein a subunit and bg dimer.
Estrogen is a lipid soluble hormone that can easily cross membranes. Knowing this, what can be concluded about estrogen receptors?
The receptors would be found inside the cell.
In some cases, just a few hormone molecules binding to the surface of a cell can trigger a very large response because _______
The signal is amplified by activation of enzymes that each catalyze multiple reactions
What do G-protein coupled, enzyme-linked, and ligand-gated ion channel receptors have in common?
They change their conformation when bound to a hormone.
A substrate binding to an enzyme is most similar to a signal molecule binding to a
receptor
When a cell responds to a signal it sent this is an example of ______
Autocrine signaling
When a cell secretes a growth factor that bind to receptors on its own membrane preventing it from proliferating this is an example of ______
Autocrine signaling
Hormones are released from one cells and act on other cells in distant organs and are thus an example of _____
Endocrine signaling
When insulin is secreted from the pancreas and acts on muscle cells to increase glucose uptake this is an example of _______
Endocrine signaling
When epidermal growth factors binds to its _______ the receptor phosphorylates itself, triggering a signal transduction pathway.
Enzyme-linked receptor
After being fed glucose a cell increases its intracellular glucose concentrations by _______
Increasing membrane glucose transporters
When a cell secretes a growth factor that binds to receptors on neighboring cells causing them to proliferate this is an example of ______
Paracrine signaling
When a cell secretes a growth factor that binds to receptors on neighboring cells causing them to proliferate this is an example of _______
Paracrine signaling
Diabetics can be given the ______ insulin which binds to receptors on cells throughout the body increasing glucose uptake.
hormone
