Chapter 17 Flashcards
Which filaments are the strongest and survive in sal solutions, no ionic detergents?
Intermediate filaments
What are intermediate filaments
To enable cells to withstand mechanical stress that occurs when the cell stretches
Define desmosome
A junction that connects the plasma meme Rams of cells
Where are intermediate filaments found?
In the cytoplasm, nuclear envelope, and cell periphery
Define nuclear lamina
Strengthen the nuclear envelope
Describe the structure of an intermediate filament
A dimer is formed by two aloha helical region monomer with an amine on one side and a carboxyl on the other. This dimer forms a tetra dimer with another dimer forming in opposite directions. They array in 8 tetramers forming a rope-like structure
How do interactions occur in intermediate filaments
Noncovalently
What are the four types of intermediate filaments?
Keratin, vimetin (connective, muscle tissues), neurofilaments, nuclear lamina
Where are Keratin filaments found
Tongue, cornea, gut, or any any epithelial region in the body
What is the role of plectin
Aids in bundling intermediate filaments and links them to other skeletal protein networks
Explain he assembly and disassembly of nuclear lamina
When phosphorylated, kinase weakens the binding causing dissemble. During dephosphorylation phosphate reassembles the lamina
How are microtubules built
They are built by tubulin, alpha and beta. These tubulins covalently alternate with the beta being the minus end and the alpha being the plus end. They grow by adding more to the plus side than the minus side.
How to microtubules grow?
A centrosome consist of centrioles surrounded by gamma tubulins which is a nucleation site. Each site forms a microtubule with the minus side pointing towards the centriole. The gamma tubulins forms the microtubule alone
Why do microtubules need nucleating sites?
It is much harder to start from scratch
Define dynamic instability
Allows microtubules to remodel rapidly due to without warning they can shrink or disappear
