Regulation of Animal Cell Shape Flashcards
1
Q
what are Cytoskeleton
A
- Helps maintain cell shape
- helps position the organelles within the cells
- it rapidly disassembles and reassembles
- allows for rapid changes in cell shape
- is highly dynamic but still provides stability
2
Q
what are the 4 main components of the cytoskeleton
A
- microtubules (25nm)
- Microfilaments (7nm)
- intermediate filaments (8-12nm)
3
Q
what are microtubules
A
- are composed of tubulin subunits
- have alpha and beta particles
- resists compression, resulting in helping maintain the cell shape
- they may radiate out from an organizing center
- can also provide cell motility
4
Q
what are the names of the 2 motions
A
1) flagella: ‘snake-like’ motion (sperm)
2) cilia: ‘rowing-like’ motion
5
Q
if the cell are fixed in place what makes them move
A
- cilia moves the fluid past them through beatings
6
Q
microtubules are also involved in what other motility within the cell
A
- organelle motility
- ATP-powered motor proteins can ‘walk’ organelles along microtubules
- allows vesicles, or other organelles to be transported to specific targets within the cell
7
Q
what are microfilimants
A
- are double chain of actin subunits
- they form linear strands, and 3-d networks (using branching proteins)
- resist tension
- the cortical network under the plasma membrane helps make this region less fluid and this maintains the cell shape
8
Q
what interactions between actin support cell movement
A
- motor proteins –> myosin
9
Q
what does actin-myosin interactions allow
A
- muscle contraction
amoeboid movement
cytoplasmic streaming in plants
10
Q
what are intermediate filaments made of
A
made of various proteins: keratins, lamins, neurofilaments
11
Q
describe intermediate filaments (what they look like etc)
A
- supercoiled into ‘cables’
- less dynamic than microtubules or microfilaments
- they form relatively permanent cellular structure
- good at resisting tension
- they may also remain after the cell that made them has died, e.g hair and out layer of skin
12
Q
what do intermediate filament help with
A
- maintaining cell shape
- anchoring organelles
13
Q
what are the 3 major types of cell junctions
A
- tight
- desmosomes
- gap
14
Q
describe the tight junctions
A
- hold neighboring cells tightly pressed together
- may form a continuous seal
- prevents movement of fluid across cell layers
15
Q
describe desmosomes
A
- anchoring junction
- provide attachment between sheets if cells
- act like rivets
- connected into the cell by intermediate filaments
