Term
| Cilium in cross-section showing axoneme structure |
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Definition
| 9 doublets + 2 singlets and dynein arms |
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Term
| Describe the role of a motor in the wavelength of a cilium |
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Definition
| Dynein is anchored on the alpha tubule and moves toward the negative end along the adjacent beta tubule. Dyneins are unidirectional and move towards the negative end. |
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Term
| Why would a cilium bend to the right instead of the left? |
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Definition
| Only a dew doubles are active at a time causing the cilium to bend toward the sides that are active |
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Term
| Anterograde axonal transport |
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Definition
| movement away from the cell body (kinesin), down the axon toward the synapse |
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Term
| Retrograde axonal transport |
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Definition
| movement back towards the cell body (dynein), down the synapse toward the axon |
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Term
| Where does kinesin get the energy to walk along a microtubule? |
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Definition
| From the globular head. It is an ATPase and used ATP hydrolysis to power it. |
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Term
| What does "family of protein" mean? |
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Definition
| Evolutionarily related proteins with a common ancestor |
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Term
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Definition
| Transverse tubule. Invaginations of the sarcolemma. It decreases the distance from the cell center to the sarcolemma. Nowhere is more than 2-3 microns from the membrane. The electrical signal can move across the whole membrane faster. |
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Term
| How does the binding of acetylcholine to a cholinergic receptor on a skeletal muscle cell (myofiber) trigger skeletal muscle contraction? |
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Definition
1) wave of depolarization over the sarcolemma runs across the t-tubule (invaginations of the sarcolemma decreasing the distance from the cell center to the sarcolemma)
2) this activated the DHP receptor and causes a conformation change in the t-tubule of the sarcolemma
3) this triggers the ryanodine receptor on the membrane of the sarcoplasmic reticulum and cause a conformational change
4) this makes the ryanodine channels open releasing calcium into the sarcoplasm
5) this triggers calcium to release over the sarcomeres
6) muscle contraction cycle |
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Term
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Definition
1) Calcium levels increase in the sarcoplasm
2) calcium binds to TnC
3) causes a conformation change and moves the tropomyosin
4) myosin head attaches to actin filament
5) Pi is released and it grabs tighter
6) power stroke
7) ADP leaves and ATP binds releasing the myosin from the actin
8) ATP is hydrolyzed to ADP and Pi and myosin head returns to cocked position |
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Term
| Why do dead people go into rigor mortis? |
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Definition
| Calcium levels go up and pumps aren't working. Membranes are getting leaky and all of the ATP is used up so the myosin head is not able to release from the actin filament and your muscles get stuck in a contracted state. |
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Term
| Why does rigor mortis go away after 48 hours? |
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Definition
| pH is lowered in the sarcoplasm, enzymes leek out, general collapse of compartments, lysosomal enzymes degrade everything |
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Term
| What cytoskeletal element is most associated with filopodia and lamella podia? |
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Definition
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Definition
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Term
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Definition
| binds complex to tropomyosin |
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