Hormones and Their Receptors: Understanding the Role of First and Second Messengers, Quizzes of Biochemistry

Download Hormones and Their Receptors: Understanding the Role of First and Second Messengers and more Quizzes Biochemistry in PDF only on Docsity! TERM 1 What are the first messengers DEFINITION 1 Hormones TERM 2 What are examples of secondary messangers? DEFINITION 2 cAMP, cGMP, Ca(+2), Inosityol 1,4,5 triphosphate TP3, and diacyglycerol (DAG) are examples TERM 3 Hormone DEFINITION 3 provide a mechanism to maintain homeostasis, to respond to changing metabolic conditions and to regulate cellular differentiation and genetic expression TERM 4 3 types of hormones DEFINITION 4 1. Amines- catecholamines- simple molecules that have NH2 groups at the end. (Epinephrine) 2. Proteins and peptides (peptide hormones) made from chains of amino acids (insulin, glucagons, and growth hormones) 3. Steroids- derived from cholesterol and regulate metabolism, electrolyte balance, inflammatory response and sexual function (made from lipids) basic sturcture made up of three 6-carbon rings and one 5carbon ring. (Testosterone and cortisol) TERM 5 3 Types of Receptors DEFINITION 5 7-TMS receptor- integral membrate proteins with 7-tms transmembrane alpha helical segments (G-binding proteins) 1-TMS receptor- which are proteins that a single transmembrane alpha helix that spans the membrane (tyrosine kinases, guanylate kinases) Ogliomeric Ion Channels- consists of multiple protein subunits. These channels are also called ligant gated channels because the bind of the hormone to the receptor opens the ion channel TERM 6 G-Protein Coupled Receptors DEFINITION 6 G protein-coupled receptors (GPCRs), also known as seven- transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors (GPLR), comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal transduction pathways and, ultimately, cellular responses. Also intermediaries in signal trans. from 7TMS receptors. binding sites for guanosine nucleotides. (Binary switches). Every 7TMS has a G-protein coupled. Hormone receptor mediate processes regulated by G-proteins may be stimulatory TERM 7 Agonists DEFINITION 7 A ligand that can bind to a receptor, alter the function of the receptor and trigger a physiological response. can be characterized by how much physiological response can be triggered, and the concentration of the agonist that is required TERM 8 Antagonist DEFINITION 8 Ligands that bind to a receptor but fail to activate the physiological response TERM 9 Trimeric G-proteins DEFINITION 9 Heliotrimers consisting of alpha, beta, and gamma subunits TERM 10 Quaternary Structure DEFINITION 10 arrangement of multiple folded protein or coiling protein molecules in a multi-subunit complex. For nucleic acids, the term is less common, but can refer to the higher-level organization of DNA in chromatin,[7] including its interactions with histones, or to the interactions between separate RNA units in the ribosome[8][9] or spliceosome. TERM 21 Protein Kinase A DEFINITION 21 Activity is dependent upon the level of cAMP, so when cAMP rises, cAMP binds to the two binding sites on the regulatory subunits which leads to release of the catalytic subunits. PKA directly can increase or decresase the activity of a protein. In protein synth. PKA first directly activates CREB which binds the cAMP, altering the transcription and synthesis of protein. TERM 22 Calmodulin DEFINITION 22 Intracellular calcium binding protein, binds 4 Ca(+2) and is bound by target proteins which activate Calmodulin.-- can fuel calmodulin dependent protein kinases TERM 23 Mitogen Activated Protein Kinases DEFINITION 23 Mitogen-activated protein (MAP) kinases () are serine/threonine-specific protein kinases that respond to extracellular stimuli (mitogens, osmotic stress, heat shock and proinflammatory cytokines) and regulate various cellular activities, such as gene expression, mitosis, differentiation, proliferation, and cell survival/apoptosis. TERM 24 Mitogen Activated Protein DEFINITION 24 activated by MEK, and can migrate from the cytosol to the nucleus where it phosphorylates transcription factorsthat induce the trans. of specific genes TERM 25 MAPKK DEFINITION 25 is a kinase enzyme which phosphorylates mitogen-activated protein kinase. -- dual phosphorylation is facillitated by dual- specificity MAPKK and are activated by serine/threonine phosphorylation by MAPKKK TERM 26 MAPKKK DEFINITION 26 activates MAPKK TERM 27 MEK DEFINITION 27 Activated by Raf kinase, is then phosphorylated and can branch off to other effectors but also activates MAPK MAP kinases are proline-directed serine/threonine kinases that are activated by dual phosphorylation in response to diverse extracellular stimuli Stimulated by growth and differential factors TERM 28 ERK DEFINITION 28 Stimulated by MEK (which was stim by Raf) ERK integrats signals leading tot eh ligand and cell type-specific responses... also an MAPKKK TERM 29 IRS-1 DEFINITION 29 Insulin receptor substrate 1 (IRS-1) is a protein that in humans is encoded by the IRS-1 gene. When insulin binds to one or both of the insulin binding sites, the receptor undergoes conf. changes including cross phos. which activates the tyrosine kinase activity for other target proteins such as IRS-1 Target proteins-- IRS-1 Is associated with other effector proteins such as Grb2 TERM 30 Raf-1 DEFINITION 30 Raf-kinase activates MEK TERM 31 GRB DEFINITION 31 Associated with IRS-1 and binds Sos TERM 32 Sos DEFINITION 32 Activated & bound by Grb-2 and it binds and activates Ras TERM 33 STAT DEFINITION 33 Signal transducers and activartors of transcription. Has a high affinity for specific binding sites on DNA which regulate gene expression TERM 34 JAK DEFINITION 34 Janus Kinase- tyrosine kinases- They cross posphorylate eachother which causes conformational changes that activate the two kinases for other protein substrates such as STAT TERM 35 Caffeine DEFINITION 35 Inhibits phosphodiesterase (which hydorlyzes the phosphodiester to convert cAMP to AMP) thus increases the concentration of cAMP TERM 46 Under what conditions is glucagon released in the blood stream? DEFINITION 46 Low blood glucose, or high insulin levels as well as activity, stress, exercise, and high plasma levels of amino acids (which indicates a state of starvation TERM 47 What type of receptor is the glucagon receptor DEFINITION 47 g-protein coupled receptor which increases cAMP and activates protein kinase A TERM 48 What happens when Glucagon binds to the receptor DEFINITION 48 It releases cAMP and activates protein kinase A TERM 49 What tissues contain glucagon receptors DEFINITION 49 Main site is the liver where it promotes glycogenolysis and gluconeogenesis.. it also promotes lipolysis in adipose tissues TERM 50 What are the effects of glucagon on these tissues? DEFINITION 50 the liver and kidneys break down and degrade glucagon to degrade glycogen in roughly 6 minutes TERM 51 What type of hormone is Epinephrine? DEFINITION 51 Caticholamine TERM 52 What tissue produces epinephrine DEFINITION 52 Adrenal glands TERM 53 Under what condition is epinephrine released into the blood stream? DEFINITION 53 all times but increased during times of stress TERM 54 What type of receptor are the beta-adrenergic receptors DEFINITION 54 The resting G-protein is a heterotrimer consising of alpha, beta, and gamma subunit and it is STIMULATORY TERM 55 What type of receptor are the alpha- adrenergic receptors? DEFINITION 55 Inhibitory TERM 56 What happens when Epinephrine binds to beta-adrenergic receptors? DEFINITION 56 Induces a confomtaional change that is detected inside of the cell. The binding of epinephrine activates G-protein. The activated G-protein in turn activates Adenylyl cyclase which converts ATP to cAMP and pyrophosphate TERM 57 What happens when epinephrine binds to alpha-adrenergic receptors? DEFINITION 57 Causes the exchange of GDP for GTP causing the G-alpha"i" subunit to dissociate from the G-beta-gamma dimer. and INHIBITS adenylate cyclase TERM 58 What tissues contain adrenergic receptors DEFINITION 58 Heart, tear duct, bladder TERM 59 What are the effects of epinephrine on these tissues? DEFINITION 59 increase or decrease in fuction TERM 60 Outline events that happen when Glucagon binds to its receptor? DEFINITION 60 1. Alpha G- binds to GDP-- conformational change activated 2. Activates a G-protein trimer and GDP released, bind GTP to alpha subunit 3. alpha subunit dissociates from the dimer 4. alpha subunit diffuses laterally through the membrane until it associates with adenylate cyclase 5. G-protein activates adenylyl cyclase 6. adenylyl cyclase converts ATP into cAMP and pyrophosphatate