Cells Alive 3: Cytoskeleton Flashcards
What are some of the functions of the cytoskeleton?
Support, Movement and resistance to mechanical forces
What are the 3 filaments it is composed of?
Microfilaments, intermediate filaments, microtubles
What are the characteristics of microfilaments?
Made up of actin, 5-9 nm long, assembles into helical polymers, found underneath the cells cortex, dynamic,
What is the function of microfilaments?
Cell Shape and Motility
What are the characteristics of intermediate filaments?
They are 10nm in length, alpha helixes that wind together to form dimers and then become tetramers to form “rope-like” structures, around 10nm in diameter- can bend but not dynamic
What are the functions of intermediate filaments?
Mechanical support of cell structures
What is the characteristics of microtubules?
Made up of tubulin (alpha and beta subunits that form dimers then form hollow tubules), 25nm in diameter- more rigid than actin filaments- has a positive and a negative end
What is the function of Microtubules?
Positioning organelles, intracellular transport
What is the critical nucleus phase?
You have enough energy from the binding of monomers to start polymerisation (minimal energy needed)
How does ATP increase the length of actin?
as the monomers are added ATP is hydrolysed to ADP, ADP is less stable so it’s easier for the actin monomers to then be removed
What does the + end of the microtubule contain?
tubulin that is bound to GTP,
What direction are the monomer interactions in?
end to end and side to side
Vincristine
A drug that binds to tubulin to stop it from polymerising
What is the function of tight junctions in the cytoplasm?
Seals epithelial membranes, limits passage of molecules, contributes to the maintenance of cell polarity uses Actins and Claudins
What is the function of Gap junctions?
Use connexins to connect the cytoplasm to other cells such as cardiac cells (electrical connections)
