Concept explainers
Interpretation:
It should be determined that how the given stimulants (Caffeine and theobromine) might interact with an enzyme in the cAMP pathway to enhance the effect of cAMP.
Concept introduction:
Stimulants: These are a group of drugs with many potential therapeutic uses, but also widely used and abused recreationally. Stimulants improve mood, enhance alertness and relieve depression.
Caffeine, Nicotine, Cocaine, Ecstasy … are some examples for stimulants.
cAMP is a cyclic
Enzymes are proteins that increase the
Secondary messengers are short lived intracellular signaling molecules. Elevated concentration of these type of messengers leads to rapid alteration in the activity of one or more cellular enzymes.
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Fundamentals of General, Organic, and Biological Chemistry (8th Edition)
- All the B - adrenergic receptors are linked with Gs G-protein. Physiological processes mediated by the intracellular second messenger cyclic AMP include: YOU CAN CHOOSE MORE THAN ONE A.carbohydrate breakdown by the liver (glycogenolysis) B.increased contractility (e.g. increased cardiac contractility) C.smooth muscle relaxation (e.g. bronchodilation or vasodilation) D.Triglyceride breakdown (lipolysis)arrow_forwardTrace the sequence of events in signal transduction for each of the following second messengers: cyclic AMP, inositol trisphosphate (IP3 ), diacylglycerol (DAG), and calcium ions.arrow_forwardDopamine, epinephrine (or norepinephrine) and histamine are important neurotransmitter agonists. When these ligands interact with their cellular receptors, how do they mainly elicit their responses? Choose the correct answer(s) and explain why. a) Activate adenylyl cyclase directly, leading to increased intracellular cAMP levels b) Activate phospholipase C c)Induce or inhibit synthesis of ligand specific intracellular proteins d) Open or close ligand gated ion channels e) Regulate intracellular second messengers through G-protein-coupled receptorsarrow_forward
- You are studying a cell line that expresses both GPCR-A and GPCR-B, each receptor binds the same ligand but activates different heterotrimeric G proteins that act on adenylyl cyclase. GPCR-A causes an increase in adenylyl cyclase activity, while GPCR-B causes an decrease in adenylyl cyclase activity. There is a basal level of adenylyl cyclase activity that produces a baseline CAMP concentration. Which of the following mutations would increase the intracellular levels of CAMP upon ligand addition? Select all that apply. A mutation in Gi that prevents GTP hydrolysis A mutation in GPCR-B that prevents G protein activation A mutation in GPCR-A that prevents G protein activation A mutation in Gs that prevents GTP hydrolysisarrow_forwardYou are studying a cell line that expresses both GPCR-A and GPCR-B, each receptor binds the same ligand but activates different heterotrimeric G proteins that act on adenylyl cyclase. GPCR-A causes an increase in adenylyl cyclase activity, while GPCR-B causes an decrease in adenylyl cyclase activity. There is a basal level of adenylyl cyclase activity that produces a baseline CAMP concentration. Which of the following mutations would decrease the intracellular levels of cAMP upon ligand addition? Select all that apply. A mutation in Gi that prevents release of bound GDP A mutation in GPCR-B that prevents G protein activation A mutation in GPCR-A that prevents G protein activation A mutation in Gs that prevents release of bound GDParrow_forwardIn the B-acrenergic receptor signaling pathway where desensitization occurs, what protein acts as an effector protein? The activity of the effector protein directly affects the activity of which protein in this pathway? How would the presence of a GAP affect the desensitization process? stimulate it inhibit it have no effect What is the actual mechanism by which desensitization occurs? the receptor is ubiquitinated the hormone is phosphorylated the hormone is degraded the receptor is internalizedarrow_forward
- Provide annotated structure image/diagram of the EPH RECEPTOR B2 (EPHB2). Giving the ligand bidning sites.arrow_forwardIn the liver and muscle cells, epinephrine stimulates the release of glucose from glycogen by inhibiting glycogen synthesis and stimulating glycogen breakdown. Outline the signaling events that occur after epinephrine binds to its receptor and the resultant increase in the concentration of intracellular cAMP and release of glucose.arrow_forwardExplain how mutations in the following proteins might result in either loss of responsiveness to a given hormone or production of a continuous signal even in the absence of the hormone: a mutation in the regulatory (R) subunit of cAMP-dependent protein kinase, making R incapable of binding to the catalytic (C) subunitarrow_forward
- Depending on the size and complexity of the molecule, small chemical alterations can impart significant activity differences, especially if a certain part of the molecule is critical for binding. Considering this, select structure(s) below that are expected to have high cholinergic agonist activity based on what we leamed about acetylcholine's SAR.arrow_forwardWhich of the following steps amplify the epinephrine signal response in cells: receptor activation of G protein, G protein activation of adenylyl cyclase, cAMP activation of PKA, or PKA phosphorylation of glycogen phosphorylase kinase (GPK)? Which change will have a greater effect on signal amplification: an increase in the number of epinephrine receptors or an increase in the number of Gαs proteins?arrow_forwardList examples of paracrine chemical messengers that playa role in modulating pain or are peptide growth factors.arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning