Exam 3 Oakes Cytoskeleton I Flashcards
Explain the four functions of the cytoskeleton
Functions of the cytoskeleton:
- Gives cells shape
- Critical component of cell division
- Structure and Polarity
- Cargo Transport
_______ act as highways within the cells to transport material to specific points in the cell
Microtubules acts as highways to transport materials to specific points in the cell
List the four main components of the cytoskeleton
Main components of the cytoskeleton:
Actin
Microtubules
Intermediate Filaments (IFs)
Septins
Explain the basics of actin (structure and function)
Actin is polarized, it has a pointed and barbed end
Actin helps with: giving cell shapes, supports plasma membrane, helps with contraction
Explain the basic structure and function of microtubules
Microtubules are polarized with a + and - end
They help with positioning organelles, intracellular transport tracks
think highway
Explain the basic structure and funciton of IFs
IFs are a family of proteins that are not polarized
They provide mechanical strength (protects the cell from damage)
Think of IFs as protective padding
Explain the basic structure and function of septins
Septins have 13 different isoforms
Made of up oligomers that have palindromic repeats
Function: support PM, cillia, flagella
Each type of cytoskeletal filament is constructed from ______
Small soluble subunits assemble into large filamentous polymerrs
FINITE resources
Each type of cytoskeletal filament is constructure from smaller protein subunits: alpha coiled coils, actins, and tubulins
Of the four types of cytoskeletal parts, which ones are polarized and which ones are single proteins?
Actin and microtubules are polarized
Actin and microtubules are also single proteins
What type of bonds are important for the fast assembly and degradation of cytoskeltal parts?
WEAK COVALENT interactions are important for fast assembly and disassembly
______________ regulate spatial distribution and dynamics of the cytoskeleton
Assesory proteins regulate spatial distribution and dynamics of the cytoskeleton
Explain the specific structure of actin
does it have a binding pocket?
Actin is called “g” actin for the fact that it is a globular protein, it has a binding pocket for atp
What kind of structure is tubulin? What kind of dimer, trimer, etc.
Tubulin acts as an alpha beta dimer
keratin is made up of ____ regions
Keratin is made up of coil coil regions
Important structural component of septins
Septins are palindromic
_______ provide stability
Single protofilament vs multiple protofilament
Bundled Filaments provide stability
Single protofilament: thermally unstable
Multiple protofilament: thermally stable
(this applies to actin as well)
Define persistance length
Rank the following from highest to lowest persistance length: actin, microtubules, IFs
Persistance Length: minimum filament length at which random thermal fluctuations are likely to cause it to bend (example, DNA is really floppy and has a tiny PL, where as microtubules are like steel and have long PL)
Highest to lowest PL:
Microtubules > Actin > IFs