Practice Quiz 15 (Cell signaling )
You have 15 minutes to finish the quiz.
Q.1:
In a fight-or-flight response, epinephrine released by the adrenal glands binds to a membrane receptor on a liver cell. Which the following is not an event triggered by the hormone binding to it's receptor ?
G-protein is activated which in turn leads to the production of cAMP.
Protein kinase A is acticated
MAP kinase is activated which leads to uptake of glucose and glycogen synthesis
an enzyme is activated that catalyzes the breakdown of glycogen to glucose
Q.2:
Which of the following statements about hormones or endocrine systems is false?
Hormones can act on any cell provided it has an appropriate membrane receptors.
Acetylcholine is an endocrine hormone but is it also functions as neurotransmitter
endocrine hormones are secreted into the blood.
all are correct
Q.3 :
A signal molecule can cause different responses in different cells because
different cells have membrane receptors that bind to different sides of the signal molecule
after arrival at the target cells the signaling molecule is modified by specific cellular enzymes
different enzymatic pathways in different cells can be activated by the same signaling molecule
the same signaling molecule can not cause different responses indifferent cells
Q.4 :
G-protein-linked receptors ________; whereas as tyrosine-kinase receptors __________.
are transmembrane proteins ... are found only on the inside of the plasma membrane
act by phosphorylating a protein ... open an ion channel when bound to a hormone
activate protein kinases ... activate MAP kinases
none of the above
Q.5 :
The action of histamine is an example of
endocrine signaling
paracrine signaling
signaling via neurotransmitter
signaling through cellular transport systems
Q.6.
Which statement is false
Insulin signals via the receptor tyrosine kinase pathway
insuline is released by special cells of the pancreas, through endocrine signaling
MAP kinases in the insulin signaling pathway activate enzymes resulting in glycogen synthesis
all are correct
Q.7 :
Which of the following cellular reactions are not triggered by epinephrine interacting with the beta adrenergic receptor
glycogen metabolism ( glucose formation)
lipid metabolism
smooth muscle relaxation
heart rate stimulation
all of the above are triggered by epinephrine
Q.8:
Alpha blockers which inhibits the alpha adrenergic receptor response have been successfully used in the control (reduction) of high blood pressure. How does the drug act?
Lowers heart rate
relaxes the heart muscle
prevents contraction of smooth muscle tissue, lining blood vessels
all of the above
Q.9 :
contraction of muscle cells is regulated through a stimulus of adjacent nerve cells. The stimulus is
an electrical signal
ions travelling from the nerve cell to the muscle cell
a signaling molecule released from the nerve cell opens an ion gate on the muscle cell
all of the above
none of the above
Q.10 :
Proto-Oncogenes are
genes which code for cancer causing substances
all the genes in cancerous cells
genes that transcribe proteins envolved in the cellular signaling systems
are mutated genes