Cell biologists use the term "ligand" to refer to ____
any small molecule that can bind in a specific manner to a larger one
From the perspective of the cell receiving the message, the three stages of cell signaling are
signal reception, signal transduction, and cellular response
The process of transduction usually begins
when the signal molecule changes the receptor protein in some way.
A signal molecule can cause different responses in different cells because ____
the transduction process is unique to each cell type; to respond to a signal, different cells require only a similar membrane receptor
involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid
In the yeast signal transduction pathway, after both types of mating cells have released the mating factors and the factors have bound to specific receptors on the correct cells
binding induces changes in the cell that lead to cell fusion
A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor and thereby cause a gene to be turned on or off.
Membrane receptors that attach phosphates to specific animo acids in proteins are called ____.
Tyrosine-kinase receptors are characterized by their ____
enzymatic phosphorylation of tyrosine in the receptor protein
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, then activating relay proteins. Which type does this?
Which of the substances below is a protein that can hold several other relay proteins as it binds to an activated membrane receptor?
The general name for an enzyme that transfers phosphate groups from ATP to a protein is
Why are there often so many steps between the original signal event and the cell's response?
each step in a cascade produces a large number of activated products, causing signal amplification as the cascade progresses
Binding of a signaling molecule to which type of receptor leads directly to a change in distribution of ions on opposite sides of the membrane?
ligand-gated ion channel
Lipid-soluble signal molecules, such as testosterone, cross the membranes of all cells but affect only target cells because
intracellular receptors are present only in target cells
Consider this pathway: epinephrine G protein-coupled receptor G protein adenylyl cyclase cAMP. Identify the second messenger