550103
Description
Flashcards by Sophie Barrett, updated more than 1 year ago
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Created by Sophie Barrett
almost 11 years ago
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| Question | Answer |
| Why is Cell Signalling Important? | - The cells of the developing organism must respond to environment to survive, divide and differentiate. - The cell of the mature organism must survive, adapt and succeed in their environment. |
| Short Term and Rapid Effects (take hours) | e.g. altered cell excitability or cell secretion. Often involves alters ion fluxes. |
| Medium Term and Moderate Speed Responses | e.g. altered metabolism or altered gene expression. |
| Long Term and Slow Responses (take hours) | e.g. altered cell shape or cell movement. With 2nd or 3rd messengers acting on the cytoskeletal proteins. |
| What are the 5 general signalling modes? | 1. Endocrine 2. Paracrine 3. Neuronal 4. Contact Dependant 5. Autocrine |
| Describe Endocrine Signalling | Messenger is produced by cell and released into bloodstream to act at a distant cell. |
| Describe Paracrine Signalling | Messenger produced by a cell to activate another close-by cell. |
| Describe Neuronal Signalling | Electrical activity along an axon towards a synapse or to a location distant in the body. |
| Describe Contact Dependant Signalling | Cell Adhesion molecules usually involved in structural integrity or cell migration. |
| Describe Autocrine signalling. | Messenger is released by a cell to act on itself. |
| What are the 3 major types of receptor? (Found on the external cell membrane) | 1. Kinase-coupled receptors. 2. G-Protein coupled receptors. 3. Ligand-gated ion channels. |
| Describe Ionotropic Receptors | Ion channels and are ligand gated, often exist in different isoforms. e.g. glutamate receptors or acetylcholine receptors. |
| Describe Metabotropic receptors. | Usually involved in metabolic or Biochemical changes. Are either G-protein coupled receptors OR Enzyme-Linked Receptors. |
| Why are Isoforms useful? | Allow different responses to the same stimulus in different cells of the body. |
| Give an example of different responses mediated by isoforms of a glutamate receptor. | NMDA receptor: slow depolarisation and 2nd messenger activation. AMPA or KA receptor: fast depolarisation. |
| How can channel gating be regulated? | Channel modulators, co-agonists and antagonists. |
| Describe how NMDA Glutamate receptors are regulated? | Blocked by Mg2+ (voltage-dependant). Mg2+ is removed by depolarisation. Glyciene can also bing , modulating the channel current. |
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