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Flashcards in Cell Shape & Movement Deck (22):
1

cytoskeleton functions

(1) maintain cell shape

(2) structural support

(3) locomotion / movement

(4) transport materials w/in cells

2

types of cytoskeleton

(1) actin filaments

(2) intermediate filaments

(3) microtubules

3

actin filament

- motor: myosin
- subunit: actin
- strucutre: strands in double helix
- 5-10% of total proteins in cell

aka microfilaments

4

actin filament functions

(1) cell shape

(2) move cells

(3) divide animal cells in two

(4) move organelles & cytoplasm in plants, fungi & animals

5

intermediate filament

- structure: fibers wound into thicker cables
- motor: none (purely strucutral fcn)

6

intermediate filament subunits

(1) keratin

(2) lamins

(3) others

7

intermediate filament function

(1) cell shape

(2) anchor nucleus & other organelles

8

actin filament types of movement

(1) cytokinesis

(2) cytoplasmic streaming

(3) cell crawling

(4) muscle

9

microtubule

- structure: hollow tube
- motor: dynein & kinesin
- subunits: ∝-tubuline & β-tubuline

10

microtubule function

(1) cell shape

(2) move cells via flagella/cilia

(3) move chromosomes during cell division

(4) assist cell plate formation during plant cell division

(5) move organelles

(6) provide tracks for intracellular transport

11

(+) end in microfilament

where things get on

12

(-) end in microfilament

where things get off

13

cytokinesis

division of cytoplasm to form 2 daughter cells
- process of cell division
- typically occurs immediately after nucleus divides in mitosis/meiosis
- actin-myosin interactions pinch membrane in 2

“cell-moving”

14

cytoplasmic streaming

directed flow of cytosol & organelles (that facilitate material distribution) w/in plant & fungal cells
- occurs along actin filaments
- actin-myosin interactions move cytoplasm around cell
- common in large cells

15

cell crawling

form of cellular movement
- involves actin filaments in which the cell produces bulges (pseudopodia) that stick to substrate & pull the cell forward
- occurs in wide range of organisms & cell types

(aka) amoeboid motion

16

microtubule organizing center (MTOC)

any structure that organizes microtubules in cells
- where microtubules originate from

17

centrosome

microtubules organizing center (MTOC) for cell’s cytoskeleton
- structure containing 2 centrioles
- responsible for spindle apparatus during cell division
- found only in animal & fungal cells

18

centriole

1 of 2 small cylindrical structures found together w/in centrosome near nucleus of eukaryotic cell (not plants)
- microtubule triplets
- structurally identical w/ basal body

19

basal body

microtubule organizing center for cilia & flagella in eukaryotic cells
- 9 triplets of microtubules arranged in circle
- establishes axoneme structures
- located @ base of microtubules
- important for axoneme growth
- foundation for microtubule

20

cilium

one of many short, filamentous projections of some eukaryotic cells
- core = microtubules
- fcn: move cell & circulate fluid/particles around surface of stationary cell

21

flagellum

long, cellular projection that undulates (eukaryotes) or rotates (prokaryotes) to move cell through aqueous environment
- longer than cilia
- abundance & pattern of movement diff. than cilia
- underlying organization identical to cilia

22

axoneme

structure found in eukaryotic cilia/flagella
- responsible for their motion
- 2 central microtubules surrounded by 9+2 arrangement (nine doublet microtubules)