Term
| what are the 3 major elements of the cytoskeleton? |
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Definition
-intermediate filaments
-microtubules
-actin filaments |
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Term
| intermediate filaments: str, loc, func |
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Definition
func: contribute to cell shape and strength
structure: dimer coiled cell (diameter of 10nm is in between microtubules and actin filaments
loc: in the cytoplasm |
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Term
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Definition
struc: made of tubulin dimers (composed of an alpha and beta cell) 25 nm diameter. ALWAYS comprised of 13 strands and hollow in the middle
loc: in the cytoplasm of cells, MTs emanante out from the centrosome
func: 1. in the centrosome MTs organize traffic and location (~roads)
2. present in dividing cells, move cells around
3. also in cilia and flagellum |
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Term
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Definition
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Term
| what is the structure of a centriole? |
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Definition
it is amde up of 9 microtubule triplets
-9+0, 9 triples on the outside, 0 on the inside
-position of the centriole determines the location of the nucleus |
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Term
| what is "dynamic instability" |
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Definition
| -the kind of growth that microtubules have, where they polymerize but also often depolymerize (at the same end) |
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Term
| how do microtubules grow? |
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Definition
-through dynamic instability
-GROW: tubulin binds to GTP, assemble at the end of the molecule GDP becomes hydrolized to GTP
-SHRINK: filaments with GDP peel away from microtubule wall, GDP tubulin released to the cytosol |
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Term
| what is the major component of cilia and flagella? |
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Definition
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Term
| what is the difference between cilia and flagella? |
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Definition
| -cilia are short and numerous, flagella are long and range in number from 0 to usually 2 |
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Term
| what is an example of where cilia are located in humans? |
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Definition
| ex. in the epithelial cell cilia beat to move the mucus out of lungs |
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Term
| what is the name of the movement of cilia and flagella? |
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Definition
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Term
| What is the structure of the base of a flagellum or cilia? |
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Definition
| 9 + 0, groups of three microtubules just like the centriole. |
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Term
| what is the structure of the outer structure in flagellum? |
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Definition
| the outer structure is 9 +2 comprised of doublet microtubules that have dynein arms that connect the doublets. the cage like structure causes bending--> wave motion |
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Term
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Definition
| arms involved in the strctural component of cilia and flagella, when the motors attached to the dynein arms work it causes the doublets to slide and the cilia to bend |
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Term
| what side of the microtubule doublets do the dynein arms move towards? |
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Definition
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Term
| what is an example of another structure holding the MT doublets in flagella together? |
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Definition
| linking proteins that rotate (kind of like arms accepting angle of the oar) when the MT doublets bend, they link the doublets, they just aren't what causes them to move |
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Term
| what aspect of the dynein arms causes the doublets to bend? |
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Definition
| the fact that one side moves while the side with 2 arms is anchored |
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Term
| what are the major differences between flagella in bacteria and flagella in eukaryotic cells? |
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Definition
| flagella in bacteria have a rotary motor, don't wave, rotate around axis, flagellin is what is on the inside and then the sheath outside, the structure is pretty rigid (kind of like a propeller with only 1 thing sticking out) |
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Term
| Why are Micro tubules important to organelles? |
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Definition
| because they act as tracks or roads that organelles move along |
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Term
| which motor proteins walk to the positive end of MTs? |
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Definition
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Term
| do dynein arms ever walk to the + side of MTs? |
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Definition
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Term
| How do dynein motor proteins move along MT tracks? |
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Definition
1. ATP binds to protein
2. configuration changes (steps forward)
3. ATP is hydrolized (protein changes config. again)
4. back to original state |
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Term
| what is the 3rd function of MTs we didn't discuss? |
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Definition
| moving chromosomes around during cell division |
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Term
| what are the 4 functions of actin filaments? |
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Definition
1. to support microvilli in cells
2. run in between attachment points in cells to add stability
3. move depolymerized actin filmaents by repolymerizing them to push cell membrane forward (i.e. cell movement by expanding membrane)
4. participation in cell division |
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Term
| what is the structure of actin filaments? |
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Definition
| globular protein (G actin) |
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Term
| what structure does actin form? |
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Definition
| 2 strands of globular proteins twisted into a helix |
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Term
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Definition
| with ATP, "treadmilling" assemble at one end, dissassemble at the other |
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Term
| what other structures bind to actin to help it do various jobs? |
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Definition
| accessory proteins and cells |
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Term
| what do the 3 kinds of filaments collectively form? |
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Definition
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Term
| what is the extra cellular matrix? |
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Definition
| it is where extra filaments help cells interact with neighboring cells and helps the cell hold together (sort of what animal cells have instead of a cell wall) |
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Term
| what are the major components of the extracellular matrix? |
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Definition
collagen and elastin (which together give proper strechiness)
proteoglycan
fibronectin (anchors ECM)
Integrin (part of membrane that hooks on to anchors) |
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