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9 Cards in this Set
- Front
- Back
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Describe the range the following types and give and example of each endocrine paracrine autocrine juxtacrine intracrine |
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Which class of signal molecule is able to transverse the lipid membrane? |
steroid hormones (small and hydrophobic) |
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Describe the sequence of events which leads to a steroid hormone altering gene expression |
- diffuses through membrane - binds to an intracellular receptor - hormone-receptor complex acts as transcription factor - change in gene expression |
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List the types of cell surface receptor |
ion channel-linked receptors g-protein linked receptors enzyme-linked receptors |
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Describe the principal of ion channel-coupled receptors |
- chemical signals (neurotransmitters) is transduced into an electrical signal - a conformational change occurs when a neurotransmitter binds to a ion-gated channel –causing it to either open or close - causes the influx/efflux of ions - such as, Na+, K+, Ca2+, or Cl- - in accordance with any respective electrochemical gradient - create a change in the membrane potential |
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Describe the principal of G-protein-coupled receptors |
- ligand binds to G-protein coupled receptor, causing a conformational change which activates the cytosolic region - G-protein binds to the GPCR, causing a conformational change which causes GDP dissociates from the alpha subunit, allowing GTP to bind - alpha subunit and beta-gamma complex separate, allowing them to interact with target proteins in the cell membrane to interact with target proteins in the cell membrane - activation of target proteins (e.g. adenylyl cyclase) triggers second messengers (e.g. cAMP), causing a signal cascade which causes intracellular changes - activity is ceased when GTP is hydrolysed to GDP |
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Describe the principal of enzyme-coupled receptors |
• extracellular ligand induces dimerisation of RTK monomers
• dimer undergoes auto-phosphorytion, creating phosphotyrosine residues on cytoplasmic domain - using ATP • phosphotyrosine residues act as ‘docking sites’ for intracellular proteins, which bind and initiate signal transduction cascades e.g mitogen-activated protein kinase (MAPK) pathway |
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What are the types of electrical and chemical signals |
electrical: ions chemical: neurotransmitters, hormones and growth factors |
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Summarise adrenergic signalling |
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