bio 150: ch 9 quiz

membrane-bound signals bind to receptors on adjacent cells in the process of ____

contact-dependent signaling

when a cell makes a cell membrane bound growth factor that binds to receptors on neighboring cells causing them to proliferate, this is an example of

contact-dependent signaling

what would interfere with actions of epinephrine through a G-protein coupled receptor?

a different molecule that binds to the G-protein coupled receptor

what would interfere with the binding of estrogen to the estrogen receptor

a molecule that prevents estrogen from entering the nucleus

when epinephrine binds to its G-protein linked receptor _____ is activated producing ____

adenylyl cyclase cAMP

the production of second messengers in signal transduction offers at least two advantages, speed and ____

amplification

programmed cell death is known as

apoptosis

Acetylcholine is a neurotransmitter that conducts a signal from a neuron to a muscle cell, causing it to contract. Atropine is a muscle relaxant that competes with acetylcholine, blocking its activity. Formulate a description of the mechanism by which atropine works,

atropine prevents acetylcholine from binding to a ligand-gated ion channel on the muscle cell

an example of ____ is when cells release signals that affect themselves and nearby target cells

autocrine signaling

when a cell secretes a growth factor that binds to receptors on its own membrane preventing it from proliferating, this is example of

autocrine signaling

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

the process through which cells can detect and respond to signals in their extracellular environment is

cell communication

in extracellular signaling, ligands bind to

cell surface receptors

When epidermal growth factor binds to its _____________ the receptor phosphorylates itself, triggering a signal transduction pathway.

enzyme-linked receptor

true or false: if epinephrine increases glycogen metabolism in muscle cells, it would have the same function in brain cells

false

estrogen is a lipid soluble hormone that can easily cross membranes. Knowing this, what can be concluded about estrogen receptors?

receptors would be found inside the cell

in mammals, receptors for ____ are intracellular

steroid hormones

A mutation in a G-protein prevents the alpha-subunit from dissociating from the beta/gamma-subunit. What effect will this have on the pathway in which the G-protein is involved?

the pathway will be underactivated

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

in _____, signals pass through a cell junction from one cell to adjacent cells

direct intracellular signaling

cells release signals that travel long distances to affect target cells during

endocrine signaling

hormones are released from one cell 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

Diabetics can be given the ____ insulin which binds to receptors on cells throughout the body increasing glucose uptake.

hormone

in ____, cells release signals that affect nearby target cells

paracrine signaling

intracellular receptors are activated by signaling molecules that _____ the plasma membrane

pass through

most types of enzyme-linked receptors function as ____

protein kinases

consider two membrane receptors on the same cell. when receptor 1 is activated, enzyme 1 becomes active within the cell. when receptor 2 is activated, enzyme 2 becomes active within the cell. when both receptors 1 and 2 are activated, only enzyme 2 is active (there is no enzyme 1 activity). what is the best explanation for this pattern of activity?

there is crosstalk between these signaling pathways

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

after estrogen binds to receptors, these estrogen receptors gain ____ activity

transcription factor

true or false: apoptosis is used in humans in order to eliminate cells infected by viruses, cells that are worn out, and those that have the potential to cause cancer

true

true or false: one common feature with G-protein coupled, enzyme-linked, and growth factor receptors is that their activation leads to activation of protein kinases.

true

a phosphatase is a capable of dephosphorylating molecules. what would this enzyme do in a signal transduction pathway that used a kinase cascade?

turn off the cascade

smooth muscle cells in the airways relax while those in the blood vessels contract in respond to the hormone epinephrine. what would expect to be different in these two types of cells exposed to epinephrine?

types of proteins expressed