What are the functions of the Cytoskeleton?
(strength, structure, organization)
What are the 3 types of Cytoskeletal Filaments?
What is the function of Intermediate filaments?
Provides strength and resistance to mechanical stress
Intermediate Filaments are found where?
In the Cytoplasm and Nuclear Envelope
What are 2 examples of Cytoskeletal Filaments?
Function of Keratin?
skin cells; that provide mechanical stability through desmosomes
Function of Lamins?
Nuclear Envelope support; Disassembles during cell division via phosphorylation
How and when do Lamins disassemble?
During cell division via phosphorylation
Describe the composition of Intermediate Filaments?
Rope-like structure made of a-helical proteins
made stable by non-covalent bonds
-globular head and tail regions (which vary allowing diff functions)
Mutation in IFs that makes skin prone to mechanical injury is known as what?
Epidermolysis Bullosa Simplex
Defective Lamins that cause premature aging due to nuclear instability is known as what?
Progeria
Describe the structure of Microtubules.
Hollow tubes composed of Tubulin Dimers (alpha and beta tubulin)
Walls formed by 13 protofilaments
Describe the structural polarity, growth and shrinkage of Microtubules.
the plus (+) end grows
the minus (-) end shrinks
What are the functions of Microtubules?
Which type of Cytoskeletal Filament is found in Cilia and Flagella for motility?
Microtubules
The Microtubule-Organizing Center is known as what?
Centrosome
The Microtubule-Organizing Center is located where?
near the nucleus
The Centrosome is located where?
Near the Nucleus
The Centrosome is composed of what?
y-tubulin rings that nucleate microtubule growth
The y-tubulin rings in Centrosomes do what?
Nucleate Microtubule growth
True or False: Microtubules grow and shrink independently.
True
Microtubules grow/shrink due to what?
GTP Hyrdrolysis
In Microtubules, GTP-Tubulin dimers cause what to occur?
growth of microtubules
In Microtubules, GDP-Tubulin dimers cause what to occur?
disassembly of microtubules