Lecture 13

Question 1

Cell organization

Answer 1

-Cells have to organize themselves in space and interact mechanically with their environment
-cells have to have the right shape, structured right internally, have to transport molecules through the cytoplasm, cells have different forms of mobility and rearrange their internal components as they grow and divide
-all these behaviors are mediated by a remarkable system of filaments, CYTOSKELETON
-

Question 2

Examples of organization

Answer 2

pulling chromosome apart (mitosis)
splits cells into 2
drives and guides intracellular traffic of organelles
ferries material one part of cell to the other
supports fragile membrane
provides mechanical linkage
allows cell to swim and crawl
provides machinary for concentration
in the nerves (dendrites)
guides the growth of plant cell wall
controls diversity of shape

Question 3

Size classes

Answer 3

-arrays of protein filaments traverse through the cytoplasm
-Three size classes are microtubles, intermediate filaments and microfilaments

Question 4

3 classes of cytoskeletal filaments

Answer 4

Microtubules-they emanate from the centrosome near the nucleus. These determine the position of the membrane enclosed organelles and direct intracellular transport

Intermediate filaments–provide mechanical strength and resistance to shear stress

Microfilaments determine the shape of cells surface and necessary for whole cell locomotion

Question 5

3 classes of cytoskeletal filaments

Answer 5

-are ineffective on their own
-effectivity depends on number of accessory protiens that will link the filament to other cell components as well as each other
-accessory proteins are essential for assembly of cytoskeltal filaments and it includes the motor proteins that either move organells along filament or filament themselves
-these filaments are dynamic and adapatable