Becker's World of the Cell (9th Edition)
9th Edition
ISBN: 9780321934925
Author: Jeff Hardin, Gregory Paul Bertoni
Publisher: PEARSON
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Chapter 23, Problem 23.2PS
QUANTITATIVE Pure agony. Agonists are drugs that bind to receptors and activate them, like their normal ligands. Suppose you work for a pharmaceutical corporation, and you are testing the receptor affinity of a new preparation of phenylephrine, which is primarily used as a selective agonist of α1-adrenergic receptors in over-the-counter decongestants. Physiological ligands for α1-adrenergic receptors are epinephrine and norepinephrine. Assume that phenylephrine can saturate the receptors in this assay to the same extent as its normal ligands if enough phenylephrine is added (that is, phenylephrine can bind nearly 100% of the receptors if enough is added). You measure the Kd for epinephrine, norepinephrine, and phenylephrine and find it is 63, 196, and 239 nM, respectively. Draw a graph that represents the change in percent of α1-adrenergic receptors bound versus concentration for each ligand. Be sure to label your axes and the curve for each ligand. Indicate the Kd for each on your graph.
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Chapter 23 Solutions
Becker's World of the Cell (9th Edition)
Ch. 23 - One effect of the hormone insulin is to cause...Ch. 23 - You are working on a new species of sea urchin...Ch. 23 - The Ca2+ concentration in unstimulated cells is...Ch. 23 - Prob. 23.3CCCh. 23 - Prob. 23.4CCCh. 23 - Prob. 23.5CCCh. 23 - Chemical Signals and Second Messengers. Fill in...Ch. 23 - QUANTITATIVE Pure agony. Agonists are drugs that...Ch. 23 - Heterotrimeric and Monomeric G Proteins. G...Ch. 23 - Calcium Chelators and Ionophores. In addition to...
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- True or False. The binding affinity between a peptide agonist and its specific G protein coupled receptor alone determines the sensitivity of a cell to the agonist peptide.arrow_forwardDear Expert. Thank you for your advice, which is good and helpful. I note that your answer is "when 3 binding sites have been occupied the activity of these receptors is maximum." However, I also note that for a similar question (see below) on α7 nicotinic Acetylcholine Receptor (nAChR) also gives the same answer, ie. at least 3 agonist binding sites should be occupied. Another Question - "To maximize the activity of an α7 nAChR, how many agonist binding sites should be occupied." I understand that in α7 nAChR, binding to two sites is more effective and binding to three sites is most effective for activation. On the other hand, binding to four or five sites in the nAChRs of chromosome 7 speeds up desensitization more than activation. Therefore, to maximize the activity of an α7 nicotinic Acetylcholine Receptor (nAChR) is also "3 sites". Am I right?arrow_forwardPlease ASAP, Thankyou. For epilepsy mention at least 2 agonists or antagonists and related them to neurophysiology (action potential and current-voltage graphs).arrow_forward
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