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Name: ________________________________________ Block: ___ Date: _____AP Biology – Mrs. AlvarezCell Communication (Ch 11)Study GuideKey Concepts (be able to elaborate, give examples, provide evidence, analyze given data, perform calculations)MCAS: Recognize that communication among cells is required for coordination of body functions. The nerves communicate with electrochemical signals, hormones circulate through the blood, and some cells produce signals to communicate only with nearby cells.AP Standards: (be able to provide supporting examples, explanations and details for each claim)Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.Cells communicate by cell-to-cell contact. Plasmodesmata between plant cells allow material to be transported from cell to cell. Immune cells interact by cell-cell contact, antigen-presenting cells (APCs), helper T-cells and killer T-cells.Cells communicate over short distances by using local regulators that target cells in the vicinity of the emitting cell.NeurotransmittersQuorum sensing in bacteriaPlant immune responseMorphogens in embryonic developmentSignals released by one cell type can travel long distances to target cells of another cell type.Endocrine signals are produced by endocrine cells that release signaling molecules, which are specific and can travel long distances through the blood to reach all parts of the body.431405317189600Example:InsulinHuman growth hormoneThyroid hormonesTestosteroneEstrogen Signal transduction pathways link signal reception with cellular response.Signaling begins with the recognition of a chemical messenger, a ligand, by a receptor protein.Different receptors recognize different chemical messengers, which can be peptides, small chemicals or proteins, in a specific one-to-one relationship.A receptor protein recognizes signal molecules, causing the receptor protein’s shape to change, which initiates transduction of a signal.Example:G-protein linked receptorsLigand-gated ion channelsReceptor tyrosine kinasesSignal transduction is the process by which a signal is converted to a cellular responseSignaling cascades relay signals from receptors to cell targets, often amplifying the incoming signals, with the result of appropriate responses by the cell.Second messengers are often essential to the function of the cascade.ExampleLigand-gated ion channelsSecond messengers, such as cyclic GMP, cyclic AMP calcium ions (Ca2+) and inositol triphosphate (IP3)Many signal transduction pathways includeProtein modifications (ex. Methylation changes signaling processes)Phosphorylation cascades in which a series of protein kinases add a phosphate group to the next protein in the cascade sequenceChanges in signal transduction pathways can alter cellular response.Conditions where signal transduction is blocked or defective can be deleterious, preventative, or prophylacticExample:Diabetes, heart disease, neurological disease, autoimmune disease, cancer, choleraEffects of neurotoxins, poisons, pesticidesDrugs (hypertensives, anesthetics, antihistamines, birth control drugs)Skills: Provide an example and explain cell communication through cell-to-cell direct contact or through chemical signaling.Create a representation that depicts how cell-to-cell communication occurs by direct contact OR from a distance through chemical signaling. Describe a model that expresses the key elements of signal transduction pathways by which a signal is converted to a cellular response.Justify claims based on scientific evidence that changes in signal transduction pathways can alter cellular responses. Describe a model that expressed key elements to show how change in signal transduction can alter cellular response. Provide an example and explain how certain drugs affect signal reception, and consequently, signal transduction pathways.AP Bio Content: Vocabulary and Key ConceptsCh 11.1Fight-or-flight response HormoneAdrenal glandHormonal signalingEpinephrineApoptosis Mating yeast cellsType a cellType α cellSignal transduction pathwayBonnie Bassler (microbiologist)Evolution of signaling mechanismsQuorum sensingBiofilm formationLocal signalingCell junctionsGap junctions (animal)Plasmodesmata (plant)Cell-cell recognitionMessenger moleculesLocal regulatorsGrowth factorsParacrine signalingSynaptic signalingNeurotransmitterSynapseTarget cellLong-distance signalingNerve signalHormones Hormonal signaling (Endocrine signaling)Plant hormones (plant growth regulators)Ethylene – ripens fruit; regulates growth (C2H4)Insulin – regulates blood sugar levelsSignal receptionSignal transductionCellular responseCh 11.2Signal receptionReceptor proteinLigandAggregation of receptor moleculesTransmembrane receptors change shapeTransmembrane receptors can aggregate3 types of cell-surface transmembrane receptors (see Fig 11.7)G protein-coupled receptors (GPCRs)Single responseReceptor tyrosine kinasesMultiple responsesIon channel receptorsReceptor malfunction disease (cancer, heart disease, asthma)G protein – binds to GTPGTP moleculeGDP moleculeReceptor tyrosine kinasesAttach P to amino acid tyrosine Kinase Dimer (2-unit molecule) Dimerization Relay proteinRole of Na+ and Ca2+ Voltage-gated ion channelsIntracellular receptorsCytoplasmNucleus Hydrophobic chemical messengers: steroid hormones; thyroid hormone in animalsTestosterone protein receptor nucleus turns on male dev. genes Small chemical messengers: NO (nitric oxide)See dropping signals worksheetDNA (transcription) RNA (translation) proteinDNA RNA proteinTranscription factors turn on specific genesCh 11.3Signal transductionMultiple steps enable amplificationFine-tuning of responseCoordination and regulation of responseRelay proteinsProtein interactionsPhosphorylation and dephosphorylation regulate protein activityProtein kinasePhosphorylation cascade (Fig 11.10)Protein phosphatases – removes P groupsSecondary messengers (small, non-protein)Cyclic AMP (cAMP)Ca2+Cholera bacterium modifies a G protein Cytosolic Ca2+ concentrations – low (Fig 11.13)Phospholipase C, IP3 and Ca2+ (Fig 11.14) Ch 11.4Cellular responseNuclear vs. cytoplasmic responseFind-tuning the responseSignal amplificationSignaling efficiencyScaffolding proteins (Fig 11.19)Signaling complexesSignal terminationCh 11.5ApoptosisEmbryonic developmentCaspasesCytochrome cApoptotic signalCh 11 Main IdeasExternal signals are converted to responses within the cell Microbes demonstrate processes also found in multicellular organismsSuggests early evolutionary origin of signaling mechanismsQuorum sensing can elicit group behavior in bacteriaSignals can be local – paracrine, autocrine, juxtacrine (neurotransmitters; short-lived molecules)Signals can travel long distances – endocrine (hormones)Reception: Signaling molecule binds to a receptor protein, causing it to change shape. 3 main typesG protein-coupled receptors (GPCRs)Tyrosine kinases (RTKs)Ligand-gated ion channelsTransduction: Cascades of molecular interactions relay signals from receptors to target molecules in the cell Phosphorylation cascades controlled and regulated byProtein kinasesProtein phosphatasesSecond messengers are small, easily diffused within the cellcAMPCa2+Nitric oxide (NO)Response: Cell signaling leads to regulation of transcription (copying a gene) or cytoplasmic activity.Nuclear response is due to turning genes on/off using a transcription factorSteroids function as transcription factorsSignaling pathways can be amplified within the cell, with ability to regulate response at each stepScaffolding proteins increase signal transduction efficiencyTermination of signal can quickly be done by reversing the ligand binding Apoptosis (cell death) integrates multiple cell-signaling pathways Apoptosis = programmed cell deathApoptotic signaling pathways exist in animal and plant cells –they are inactiveActivation can come from internal or external cell signalsHighlighted case examples: Epinephrine hormone from adrenal gland in animals / humansQuorum sensing from Vibrio fisherii bacteria living in Hawaiian Bobtail SquidInsulin hormone from pancreas in animals / humansDopamine neurotransmitter hormone from neurons in brain in animals / humansRock Pocket Mouse fur color due to the functioning of the transmembrane MCR1 protein receptor in melanocytes Application: Analysis of pathway charts and modelsAnalysis of data and graphs Explanation of sequential signal transduction events Summary lessonSkits of cell signaling / check for understanding of signal transduction (15 min)Application: Neurotransmitter animation (Prialt – see below) – 5 minPrezi – David Knuffke Cell Communication 1 of 5 (20 min)Application: Morphogens in embryonic development (Concentration of signal molecule triggers transcription – see below) (5 min) Application: Biochemistry and Cell Signaling in Rock Pocket MouseVideo (6 min)Intro new terms: (5 min) PhenotypeWild-type vs mutant MC1R Central Dogma review: DNA (transcription) RNA (translation) proteinTranscription factor – MC1RMelanocyteWorksheet (40 min) – complete as HWWorksheet – debrief (10 min)Inner Life of Cell – with narration (10 min)Review (20 min)Lesson Resources: Prialt block motor synapse in fish Prialt blocks pain signaling in mice Concentrations of Signal Molecules trigger transcription factors – cell differentiation Rock Pocket Mouse – up to 5:30min Additional:Synaptic function – basic intro Prezi adapted from Mr. David Knuffke Cell Communication Prezi and Video Links PREZICellular Communication adapted from Mr. David Knuffke VIDEOSPrialt block motor synapse in fish Prialt blocks pain signaling in mice and humans Concentrations of Signal Molecules trigger transcription factors – cell differentiation Rock Pocket Mouse – up to 5:30min Additional:Synaptic function – basic intro ................
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