Ch. 16 Flashcards
- Signaling by the steroid hormone estrogen is an example of _______ signaling.
a. autocrine
b. endocrine
c. paracrine
d. direct cell-to-cell
endocrine
- Signaling by neurotransmitters is an example of _______ signaling.
a. autocrine
b. endocrine
c. paracrine
d. direct cell-to-cell
paracrine
- Stimulation of T lymphocytes, leading to their synthesis of a growth factor resulting in T lymphocyte proliferation, is an example of _______ signaling.
a. autocrine
b. endocrine
c. paracrine
d. direct cell-to-cell
autocrine
- Signaling by cadherins is an example of _______ signaling.
a. autocrine
b. endocrine
c. paracrine
d. direct cell-to-cell
direct cell-to-cell
- Steroid hormones usually act via receptors that
a. are coupled to G proteins that activate adenylyl cyclase.
b. activate tyrosine kinases.
c. bind to DNA.
d. activate phospholipase C.
bind to DNA.
- Which of the following signal molecules binds to nuclear receptors?
a. Thyroid hormone
b. Vitamin D3
c. Retinoic acid
d. Estrogen
Thyroid hormone, Vitamin D3, and Estrogen
- A glucocorticoid binding to its receptor stimulates
a. phosphorylation of a transcription factor protein that activates a gene.
b. formation of a receptor dimer that triggers an intracellular signal pathway.
c. formation of a receptor dimer that binds to and activates a gene.
d. binding of the receptor monomer to a gene.
formation of a receptor dimer that binds to and activates a gene.
- Neurotransmitters act by binding to receptors that are
a. ligand-gated ion channels.
b. located in the cytoplasm.
c. tyrosine-kinase receptors.
d. not coupled to G proteins.
ligand-gated ion channels.
- Which of the following stimulates fibroblasts to proliferate and thus heal a wound?
a. EGF
b. NGF
a. NO
d. PDGF
PDGF
- Aspirin inhibits _______ synthesis.
a. abscisic acid
b. vasopressin
c. estrogen
d. prostaglandin
prostaglandin
- All eicosanoids are synthesized from
a. cholesterol.
b. arachidonic acid.
c. prostaglandin.
d. thromboxane A.
arachidonic acid.
- In plants, cytokinins stimulate
a. cell division.
b. cell elongation.
c. cell enlargement.
d. fruit ripening.
cell division
- In plant cells, auxin binds to a
a. cell surface receptor and triggers the ras/raf pathway.
b. nuclear receptor that changes its shape so that it can bind to and activate genes.
c. receptor ubiquitin ligase that stimulates the degradation of transcriptional repressors, resulting in activation of genes.
d. cell surface molecule that stimulates fluid uptake.
receptor ubiquitin ligase that stimulates the degradation of transcriptional repressors, resulting in activation of genes.
- The G protein that activates adenylyl cyclase is a
a. monomeric G protein in the Ras family that binds GTP.
b. dimeric G protein that separates into and subunits.
c. trimeric G protein that separates into α and βγ subunits
d. heterotrimeric G protein that separates into and subunits
trimeric G protein that separates into α and βγ subunits
- The GTP on the G protein that is linked to adenylyl cyclase is split to GDP and Pi
a. in the inactive state.
b. in the process of subunit separation.
c. upon activation by the receptor.
d. by the active subunit.
in the inactive state.
- In an active state of a G protein,
a. the subunit binds to a target protein and the subunit remains bound to the receptor.
b. the α and βγ subunits both can bind to target proteins.
c. the and subunits both can bind to target proteins.
d. the subunit can bind to a target protein and the subunit remains bound to the receptor.
the α and βγ subunits both can bind to target proteins
- Cholera toxin inhibits the ability of the α subunit of Gs to split GTP. The resulting effect is the _______ of adenylyl cyclase
a. stimulation
b. inhibition
c. molecular degradation
d. increased synthesis
. stimulation
- The major function of cAMP in animal cells is to activate
a. adenylyl cyclase.
b. protein kinase A.
c. protein kinase C.
d. tyrosine kinases.
protein kinase A
- Protein kinase A is activated by
a. phosphorylation of its catalytic subunit.
b. phosphorylation of its regulatory subunits.
c. binding of cAMP to its catalytic subunits.
d. binding of cAMP to its regulatory subunits.
binding of cAMP to its regulatory subunits.
- Which of the following is not considered a second messenger?
a. cAMP
b. IP3
c. Calcium
d. Ecdysone
Ecdysone
- Protein kinase A regulates glycogen metabolism by phosphorylating glycogen synthase and
a. phosphorylase kinase.
b. glycogen phosphatase.
c. glycogen phosphorylase.
d. glucokinase.
. phosphorylase kinase
- Protein kinase A regulates glycogen metabolism by _______ glycogen synthase and _______ glycogen phosphorylase.
a. activating; activating
b. inactivating; inactivating
c. activating; inactivating
d. inactivating; activating
inactivating; activating
- CREB is activated by
a. cAMP binding in the nucleus.
b. phosphorylation by protein kinase A in the nucleus.
c. cAMP binding in the cytoplasm.
d. phosphorylation by protein kinase A in the cytoplasm.
phosphorylation by protein kinase A in the nucleus.
- Which of the following correctly describes how protein kinase A can activate genes?
a. Nuclear protein kinase A is activated by cAMP to phosphorylate general transcription factors.
b. Cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate CREB.
c. Cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate general transcription factors.
d. Nuclear protein kinase A is activated by cAMP to phosphorylate CREB.
Cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate CREB.