B Lipophobic messengers are stored in vesicles and released by exocytosis

B lipophobic messengers are stored in vesicles and

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B) Lipophobic messengers are stored in vesicles and released by exocytosis immediately after synthesis. C) Lipophobic messengers are stored in vesicles and released by simple diffusion in response to a stimulus. D) Lipophobic messengers are released immediately upon synthesis by simple diffusion. E) Lipophobic messengers are stored in vesicles and released by exocytosis in response to a stimulus. Answer: E 40) Which of the following statements best describes the release of a lipophilic messenger? A) Lipophilic messengers are stored in vesicles and released by exocytosis immediately after synthesis. B) Lipophilic messengers are released immediately upon synthesis by simple diffusion. C) Lipophilic messengers are stored in vesicles and released by simple diffusion in response to a stimulus. D) Lipophilic messengers are stored free in the cytosol and released by simple diffusion in response to a stimulus. E) Lipophilic messengers are stored in vesicles and released by exocytosis in response to a stimulus. Answer: B 41) Lipophilic hormones are transported in blood ________ and bind to receptors located ________. A) dissolved in the plasma : inside the target cell B) bound to carrier proteins : inside the target cell C) inside red blood cells : inside the target cell D) dissolved in the plasma : on the plasma membrane of the target cell E) bound to carrier proteins : on the plasma membrane of the target cell Answer: B 42) Much evidence suggests that depression might be associated with deficiencies in the biogenic amines serotonin and norepinephrine. If this is true and the body has reduced concentrations of these amines, one might predict the body would ________ in order to adapt to these lowered levels. A) reduce the affinity B) increase the half life C) downregulate D) upregulate E) increase the concentration of chemical messenger Answer: D 8
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43) What is a molecule that is similar in structure to a messenger and binds with that messenger's receptor to stimulate a similar response from the target cell? A) agonist B) antagonist C) synergist D) protagonist E) blocker Answer: A 44) As a general rule, the magnitude of a target cell's response to a chemical messenger depends on which three factors? A) (1) the solubility of the chemical messenger, (2) the location of the receptor, and (3) the affinity of the receptor to the messenger B) (1) the concentration of the messenger, (2) the number of receptors, and (3) the affinity of the receptor for the messenger C) (1) the concentration of the messenger, (2) the percent saturation of the receptor, and (3) the specificity of the receptor for the chemical messenger D) (1) the solubility of the chemical messenger, (2) the location of the receptor, and (3) the class of the receptor E) (1) the half life of the messenger, (2) the number of receptors, and (3) the percent saturation of those receptors Answer: B 45) The affinity of a receptor for its ligand is a measure of the A) ability of the ligand to permeate the plasma membrane and reach its receptor.
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