BS 161 Final Exam questions with answers

BS 161 Final Exam questions with
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answers

In yeast signal transduction, the yeast cells
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A)secrete molecules that result in response by other yeast cells.
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B)must physically and directly interact.
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C)produce signal molecules that change themselves so they can
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interact with one another. |\ |\ |\ |\




D)produce response molecules that diffuse to other yeast cells.
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E)mate, after which the new cells secrete hybrid signals. -
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CORRECT ANSWERS ✔✔A |\ |\




Which of the following is true for the signaling system in an
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animal cell that lacks the ability to
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produce GTP? |\ |\




A)It would employ a transduction pathway directly from an
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external messenger. |\ |\




B)It could activate only the epinephrine system.
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C)It would not be able to activate and inactivate the G protein on
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the cytoplasmic side of the
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plasma membrane. |\ |\




D)It would use ATP instead of GTP to activate and inactivate the
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G protein on the
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cytoplasmic side of the plasma membrane. |\ |\ |\ |\ |\ |\

,E)It would be able to carry out reception and transduction but
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would not be able to respond
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to a signal. - CORRECT ANSWERS ✔✔C
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Because most receptors are membrane proteins, which of the
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following is usually true? |\ |\ |\ |\




A)They open and close in response to protein signals.
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B)They change their conformation after binding with signal
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polypeptides. |\




C)They are only attached to one membrane surface: exterior or
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interior. |\




D)They preferentially bind with lipid or glycolipid signal
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molecules. |\




E)They lead to changes in intracellular ion concentration. -
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CORRECT ANSWERS ✔✔B |\ |\




Since steroid receptors are located intracellularly, which of the
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following is true? |\ |\ |\




A)The receptor molecules are themselves lipids or glycolipids.
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B)The steroid/receptor complex can cross the nuclear membrane.
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C)The receptor molecules are free to move in and out of most
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organelles. |\




D)The unbound steroid receptors are quickly recycled by
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lysosomes. |\




E)The concentration of steroid receptors must be relatively high
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in most cells. - CORRECT ANSWERS ✔✔B
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,The receptors for a group of signaling molecules known as
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growth factors are often
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A)cyclic AMP. |\ |\




B)ligand-gated ion channels. |\ |\ |\




C)neurotransmitters. |\




D)receptor tyrosine kinases. |\ |\ |\




E)G protein-coupled receptors. - CORRECT ANSWERS ✔✔D
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Binding of a signaling molecule to which type of receptor leads
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directly to a change in the|\ |\ |\ |\ |\ |\




distribution of ions on opposite sides of the membrane?
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A)phosphorylated receptor tyrosine kinase dimer |\ |\ |\ |\ |\




B)ligand-gated ion channel |\ |\ |\




C)G protein-coupled receptor
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D)intracellular receptor |\ |\




E)receptor tyrosine kinase - CORRECT ANSWERS ✔✔B
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If an adult person has a faulty version of the human analog to
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ced-4 of the nematode, which of
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the following is most likely to result?
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A)activation of a developmental pathway found in the worm but
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not in humans
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B)webbing of fingers or toes |\ |\ |\ |\ |\




C)a form of cancer in which there is insufficient apoptosis
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D)neurodegeneration |\

, E)excess skin exfoliation - CORRECT ANSWERS ✔✔C
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A drug designed to inhibit the response of cells to testosterone
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would almost certainly result in
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which of the following?
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A)an increase in cytosolic calcium concentration
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B)an increase in receptor tyrosine kinase activity
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C)lower cytoplasmic levels of cAMP|\ |\ |\ |\ |\




D)a decrease in G protein activity
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E)a decrease in transcriptional activity of certain genes -
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CORRECT ANSWERS ✔✔E |\ |\




Which of the following is a correct association?
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A)GTPase activity and hydrolysis of GTP to GDP
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B)adenylyl cyclase activity and the conversion of cAMP to AMP
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C)phosphorylase activity and the catabolism of glucose |\ |\ |\ |\ |\ |\ |\




D)phosphodiesterase activity and the removal of phosphate |\ |\ |\ |\ |\ |\ |\


groups |\




E)kinase activity and the addition of a tyrosine - CORRECT
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ANSWERS ✔✔A |\




An inhibitor of which of the following could be used to block the
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release of calcium from the |\ |\ |\ |\ |\




endoplasmic reticulum? |\ |\




A)tyrosine kinases |\ |\




B)adenylyl cyclase |\ |\