Exam 9: Cell Signaling

A) the cytoplasmic domain
B) the transmembrane domain
C) the ligand-binding site
D) the extracellular domain

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A) are small intracellular molecules that participate in signal transduction.
B) play a role in activation of intracellular signal transduction.
C) are removed in order to terminate a cellular signaling response.
D) amplify the effects of the signal.
E) All of these choices are correct.

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A) The cells taken from the patient have more growth factor receptors than normal.
B) The concentration of a signaling molecule in the patient is higher than usual.
C) The cells taken from the patient exhibit a reduced level of signal amplification.
D) None of the other answer options is correct.

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A) It prevents the signaling cell from producing the signal.
B) It prevents the receptor from binding to the signal.
C) It prevents the receptor from becoming activated.
D) It prevents the termination of the signal.

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A) VEGF is an endocrine-signaling molecule because it circulates through the bloodstream inside of platelets.
B) VEGF is an endocrine-signaling molecule because it is released from platelets into the bloodstream and is carried throughout the body, causing widespread activation of platelet-derived growth factor receptors on cells in a variety of tissues.
C) VEGF is a paracrine signaling molecule because it binds to receptors on cells at the site where new blood vessels are needed.

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A) paracrine, autocrine, endocrine
B) autocrine, endocrine, paracrine
C) autocrine, paracrine, endocrine
D) endocrine, paracrine, autocrine

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A) It binds small, nonpolar signaling molecules.
B) It activates a G protein.
C) It allows ions to move across the plasma membrane.
D) It triggers the activity of a phosphatase.

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Both types undergo a...

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A) contact-dependent
B) paracrine
C) autocrine
D) endocrine
E) All of these choices are correct.

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A) cystic fibrosis, which is caused by a mutation in a channel protein, resulting in a buildup of mucus
B) congestive heart failure, which is caused by chronic high blood pressure due to excessive sodium intake
C) a specific type of cancer, which is caused by a truncated receptor that becomes stuck in the activated for.
D) familial hypercholesterolemia (high cholesterol in the blood) , which is caused by a decrease in the number of receptors for cholesterol.

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A) fibroblasts cultured with serum
B) fibroblasts cultured with platelet proteins
C) fibroblasts cultured with plasma
D) The same results are obtained whether the fibroblasts are cultured with serum or with platelet proteins.

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A) protein phosphatase activity
B) protein kinase activity
C) adenylyl cyclase activity
D) phosphodiesterase activity

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A) testosterone
B) Delta
C) PDGF
D) neurotransmitters
E) Notch

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A) binding to and activating the G protein-coupled receptor in these cells.
B) binding to and inhibiting the G protein-coupled receptor in these cells.
C) causing the  subunit of the G protein to stay associated with the  and  subunits.
D) causing the  subunit of the G protein to bind GDP constantly.
E) causing adenylyl cyclase to dissociate from the membrane.

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A) These mice will have more neurons compared with their normal counterparts.
B) These mice will have fewer neurons compared with their normal counterparts.
C) These mice will have more glia compared with their normal counterparts.
D) The mice will have fewer glia compared with their normal counterparts.
E) The mice will have fewer neurons and more glia compared with their normal counterparts.

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A) binding affinity of the receptor to the signaling molecule.
B) concentration of the signaling molecule in the vicinity of the receptor.
C) level of expression of the signal transduction proteins.
D) level of expression of proteins that terminate the response.
E) All of these choices are correct.

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A) by altering the ligand-binding site of the receptor
B) through a conformational change of the receptor
C) by decreased phosphorylation of the receptor
D) by increased translation of the receptor

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