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22 Cards in this Set
- Front
- Back
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How do cells communicate with each?
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Through direct cell-cell contact and by using direct cell-cell contact.
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Ligand
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A signaling molecule.
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Paracrine signaling
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A signaling molecule that has traveled a short distance and affected nearby cells.
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Autocrine signaling
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A signaling molecule that affects the same cell that secretes it.
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Growth Factor Signaling: Flow of signaling
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1. Receptor binds the ligand and dimerizes.
2. Signaling is activated. 3.Kinase cascade 4.Transcription factor(s) are activated. 5. Gene expression changes 6. Cell Behavior changes |
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GFS: Receptor
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A protein that biochemically binds to the signal (ligand).
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Kinase
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An enzyme that phosphorylates another protein (or lipid).
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Kinase cascade
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A series of kinases that pass a signal from the receptor through sequential phosphorylation reactions.
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What control cell fates in development?
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Growth factor signaling
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Endocrine signaling
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A signaling molecule that has traveled a long distance.
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What are the main characteristics of stem cells?
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1. They are unspecialized.
2. Capable of long-term self renewal. 3. Can produce specialized cells through differentiation (induced by signaling molecules). |
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Totipotent
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Capable of forming all tissues necessary for an organism.
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Pluripotent
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Capable of forming 3 germ layers and primordial germ cells.
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Multipotent
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Capable of forming several cell types.
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Unipotent
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Form only 1 type of cell.
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How are human embryonic stem cells derived?
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1. Day 0 - In vitro fertilization
2. Day 3 - Totipotent cells 3. Day 5 - Blastocyst |
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How are stem cells grown?
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They are grown in a culture with "feeder" cells and chemicals that keep them from differentiating.
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Stem cells will self-renew or differentiate by what?
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Depending of the signaling molecules that are available at the time.
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If embryonic stem cells are injected into the body what do they form?
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A teratoma - a tumor with all cell types.
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Hematopoietic Stem Cells
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Form all of the blood cell types
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De-differentiation of adult cells
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Causes a normal body cell to form its primordial stem cell state.
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Challenges for stem cell therapy
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1. To get cells to differentiate into correct cell type.
2. Get the cells to right place in body. 3. Keep them from not not making a tumor. 4. Reduce attack by the immune system. |
