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18 Cards in this Set
- Front
- Back
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What 4 processes do cells use to communicate? |
1. Signal Transmission 2. Reception 3. Signal Transduction 4. Response |
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Signal Transmission |
In Chemical signaling, a cell must synthesize and release signaling molecules If target cells are not nearby, signal mus be transported to them |
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Reception |
- glycoproteins that bind with specific signaling molecules - many bind to the receptors on the surface of the target cell and do not actually enter the cell |
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Signal Transduction |
- a cell converts an extracellular signal into an inter-cellular signal, and relays the signal
- typically involves a chain of molecules that relay information |
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Response |
- a signal is converted into a response that alters some cell process - Ex. Open or Close plasma membrane - Termination of signal |
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Sending Signals, cells can communicate: |
1. by way of cell junctions 2. by way of electrical signals 3. by way of cell-to-cell contact 4. by way of chemical signals |
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Chemical signaling examples |
1. some cells produce local regulators that diffuse through the interstitial fluid surrounding the cells, and act on nearby cells 2. local regulators include local chemical mediators, ie., growth factors, histamine, nitric oxide (NO) and prostaglandins |
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Neurotransmitters |
Most neurons (nerve cells) signal one another by releasing chemical compounds |
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Hormones |
Are chemical messengers in plants and animals. |
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Local regulators |
diffuse through the interstitial fluid and act on nearby cells. This process is called paracrine regulation |
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Only the signaling molecule that fits the shape of a specific receptor can trigger a response in a cell |
1. different cell types produce different receptors 2. a cell may synthesize many different kinds of receptors 3. the same signal can have different meanings 4. Rhodopsin, phytocrhomes, and cryptochromes respond to non-chemical signals |
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What increases the number of receptors synthesized, and amplifies the signaling molecule's effect? |
Receptor up-regulation |
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What often involves transporting receptors to lysosomes where they are destroyed? |
Receptor down-regulation |
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What are three types of receptors that occur on the cell surface? |
Ion Channel-Linked receptor (ligand-gated channels) G-Protein receptors Enzyme-linked receptors |
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What is characteristic of an ion channel-linked receptor? |
- Found in plasma membrane - Convert chemical signals into electrical signals - Ion channel opens or closes in response to binding of the signaling molecule (ligand) |
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What is characteristic of a G protein-linked receptor? |
- Transmembrane proteins with a binding site for a signaling molecule on the outside, and a binding site for a specific G protein that extends into the cytosol - Guanine diphosphate into Guanine triphosphate |
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What is characteristic of an Enzyme-linked receptor? |
- Transmembrane proteins with a binding site for a signaling molecule outside the cell and an enzyme component inside the cell - Bind hormones such as insulin and growth factors - Tyrosine Kinase |
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What is Tyrosine Kinase? |
An enzyme that catalyzes transfer of phosphate groups (phosphorylation) from ATP to a specific tryosine that is part of a protein |
