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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EBK FUNDAMENTALS OF GENERAL, ORGANIC, A
- Trace 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_forwardAll 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_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_forwardWhat are the receptor(s) involved in caffeine binding?What kind of interaction is established between them,based on the four types of receptors below: Voltage Gated Ion Channels G-protein coupled receptor Enzyme-linked receptor Intracellular receptorarrow_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_forward
- In 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_forwardDescribe a mechanism by which a steroid hormone might act to increase intracellular levels of cyclic AMP. Match the words in the left column to the appropriate blanks in the sentences on the right. activate decrease inhibit repressed induced increase Reset Help Since steroid hormone-receptor complexes specific genes, a steroid hormone could in principle transcription of the gene for adenylate cyclase and, hence, steady-state level of this enzyme. Other possibilities could include synthesis of a phosphodiesterase inhibitor or synthesis of cAMP phosphodiesterase. the transcription of thearrow_forwardDescribe two features of insulin signaling that affect glucose utilization. Aβ-adrenergic response can be modulated through the actions of a receptorkinase and arrestin because phosphorylation by the kinase desensitizes thereceptor. How might signaling by a tyrosine receptor kinase, such as theinsulin receptor, be modulated?arrow_forward
- Which 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_forwardProvide annotated structure image/diagram of the EPH RECEPTOR B2 (EPHB2). Giving the ligand bidning sites.arrow_forwardWhich of the following contain statements that are both correct? Aspartame triggers the cellular signaling cascade via activation of cAMP as secondary messenger. Primary role of non-nutritive sweeteners is to provide energy for the body. Increase in cAMP and IP3 levels promotes increase in intracellular Ca+2 ions. Phytochemicals that elicit sweet sensation are considered natural sweeteners. Each taste buds contain only one taste receptor cell type, which results to a predominant taste modality on specific tongue locations. In a 250g carbohydrate meal, a total of 1 kcal of energy is produced. Ligand binding to G-protein coupled receptors (GPCR) promotes the activation of heterotrimeric G-proteins. G-proteins are activated through direct phophorylation of GDP that is bound to the a-subunit.arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning