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14 Cards in this Set
- Front
- Back
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What are the molecules often involved In communication between cells? |
Signalling cell which releases signalling molecules Signalling molecules Receptor molecules Receptor cells which have receptors that bind to the signalling molecules and signal is sent as a response. |
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What the 4 main steps in cell signalling? |
Receptor activation: signal binds to receptor which it then activates Signal transport: signal is transmitted to interior of cell by a signal transductor this information can then remain in cytoplasm or go to nucleus. Response: cell will respond Termination: once signal is received it is terminated so new signal can be received. |
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What are the different types of signaling? |
Endocrine signalling: used when signalling molecules need to travel great distances via the circulatory system examples are estrogen and testrogen Paracrine system: involves 2 cells close together and short distance of upto 20 cell diameter of s few hundred micrometer. Signals usually small and soluble. Autocrine signalling: occurs when signalling cell and the receptor is one and the same. Important in embryonic development as well as pancrine. Contact dependant signalling: Occurs in the absence of a signalling molecule fur to direct content and neighbouring cells. |
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What happens in ligand signalling molecules? |
When ligands bind to ligand binding site on its receptors a confrontational change in the receptor takes place that trigger chemical reactions to take place cytosol. |
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What are intracellular receptor's? |
Non polar signaling molecules that can pass through the hydrophobic core of the plasma membrane without receptors in the exterior side and inside bind to receptors in to the cell in cytosol or nucleus to form steroid receptor complex which when active often act as a transcriptional regulators to control gene expression. |
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What are the 2 states of receptor? |
On: when bound Off: when not |
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What is a g protein coupled receptor? |
Found in virtually every eukaryotic organisms and associated with g proteins bound to GDP and GTP in cytoplasm.
When bound to GTP active and GDP inactive. If bound to GTP the g protein is on and signal continues to be transmitted. |
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What is receptor kinase? |
Enzyme that adds a phosphate group to another molecule via phosphorylation. Phosphates removes a phosphate group when a protein in phosphorylate by kinase and it it's active and switched on. When ligands bind to ligand binding site receptor kinase becomes active and transmites signal from outside of cell to in. |
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What are ligand gated ion channel? |
Ion channels that open when bound to ligand. |
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How are you proteins activated? |
G protein is composed of 3 subunits alpha beta and gamma. The alpha subunit bind to GDP and all 3 subunits combine and g protein is inactive. When g protein binds to activated receptor GDP-alpha subunit complex Is replaced by GTP causing duplex to separate Gprotein is now active and able to bind and activate specific target proteins in cell. |
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What is binding affinity? |
The amount of time a signalling molecules remains bound to receptor depends on how tightly receptor holds onto molecule. |
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What are the uses of receptor kinase? |
Formation and elongation of limb buds that become arms and legs. Insulin signalling: allows transport of glucose from plasma membrane to cytoplasm. Wound healing Kit production of pigments in skin feathers scales and hairs. |
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What is dimerization? |
When signal molecules binds to extracellular portion of 2 receptors causing receptors to partners this activates cytoplasmic kinase domains causing phosphorylation at multiple site on cytoplasmic tails. Phosphorylated areas provide place for other proteins to bind and become active. |
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How. An cell signaling cause cancer? |
Many cancers can arise from problems in Cell signalling such and increased receptors overproduction of altered signaling and RAS mutation. |
