chapter 11 quiz Flashcards

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1
Q

one of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. which type does this

a: g protein coupled receptors
b:ligand gated ion channels
c:steroid receptors
d:receptor tyrosine kinases

A

receptor tyrosine kinases

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2
Q

since steroid receptors are located intracellularly which of the following is true

a: the receptor molecules are themselves lipids or glycolipids
b:the steroid/receptor complex can cross the nuclear membrane
c:the unbound steroid receptors must be quickly recycled by lysosomes
d:the concentration of steroid receptors must be relatively high in most cells
e:the receptor molecules are free to move in and out of most organelles

A

the steroid/receptor complex can cross the nuclear membrane

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3
Q

which of the following is the best explanation for the inability of a specific animal cell to reduce the Ca2+ concentration in its cytosol compared with the extracellular fluid?

a:blockage of the synaptic signal
b:loss of transcription factors
c:insufficient ATP levels in the cytoplasm
d:low oxygen concentration around the cell
e:low levels of protein kinase in the cell

A

insufficient ATP levels in the cytoplasm

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4
Q

adenylyl cyclase has the opposite effect of which of the following

a:protein kinase
b:protein phosphatase
c:phosphodiesterase
d:phosphorylase
e:GTPase

A

phosphodiesterase

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5
Q

what explains the increased concentration of Ca
++ in the ER?

a:calcium ions are actively imported from the cytoplasm into the ER
b:calcium concentration is kept low in the cytoplasm because of its high usage level
c:calcium cannot enter the plasma membrane through ion channels
d:calcium levels in the blood or other body fluids are extremely low
e: the Ca ions are recycled from other molecules in the ER

A

calcium ions are actively imported from the cytoplasm into the ER

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6
Q

what is most likely to happen to an animals target cells that lack receptors for local regulators

a:they might compensate by receiving nutrients via a factor
b:they could develop normally in response to neurotransmitters instead
c:they could divide but never reach full size
d: they might not be able to multiply in response to growth factors from nearby cells
e:hormones would not be able to interact with target cells

A

they might not be able to multiply in response to growth factors from nearby cells

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7
Q

which of the following is characterized by a cell releasing a signal molecule into the environment followed by a number of cells in the immediate vicinity responding?

a:hormonal signaling
b:autocrine signaling
c:paracrine signaling
d:endocrine signaling
e:synaptic signaling

A

paracrine signaling

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8
Q

when a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway

a:receptor
b:relay molecule
c:transducer
d:signal molecule
e:endocrine molecule

A

signal mol.ecule

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9
Q

of the following a receptor protein in a membrane that recognizes a chemical signal is most similar to

a:the active site of an allosteric enzyme that binds to a specific substrate
b:tRNA specifying which amino acids are in a polypeptide
c: a metabolic pathway operating within a specific organelle
d: an enzyme having an optimum pH and temperature for activity
e: an antibody in the immune system

A

the active site of an allosteric enzyme that binds to a specific substrate

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10
Q

which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP

a:it would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane
b:it could activate only the epinephrine system
c:it would be able to carry out reception and transduction but would not be able to respond to a signal
d:it would use atp instead of gtp to activate the g protein on the cytoplasmic side of the plasma membrane
e:it would employ a transduction pathway directly from an external messenger

A

it would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane

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