Cytoskeleton Flashcards
(40 cards)
The inside of a cells is basically an _________ ________ _________
organized super highway
Give a brief history of cytoskeleton discovery (2 dates)
1903: Nikolai Kolstov first described cytoskeleton as a network of tubules that control shape
1931: Paul Wintrebert coined cytoskeleton
What are the 3 main types of cytoskeletons?
Microfilaments (actin)
Intermediate filaments
Microtubules
Describe the shape of the 3 types of cytoskeletons
Microfilaments: 2 strands intertwined
Intermediate filaments: Like a strong rope (many strands intertwined)
Microtubules: Hollow cylinder
What are microfilaments made of?
Linear polymers of G-actin
What are microfilaments used for?
- Generate force when the growing end bashes against the membrane
- Act as a scaffold for myosin motor proteins to walk along
- muscle contraction, cell movement, intracellular transport, maintenance of eukaryotic cell shape, cytokinesis (cell division), cytoplasmic streaming.
What are intermediate filaments made of?
Tetramers of red-like proteins that are tightly bundled into long ropelike filaments
What are intermediate filaments used for?
- Provide internal scaffold to help anchor organelles and the nucleus and organize 3D structure of cell
- Maintain overall cell shape and form part of the cell-cell connections that allow cells to communicate with each other
What are mutations intermediate filaments linked to?
Premature again and muscular dystrophy
What are microtubules made of?
Hollow cylinders composed of tubulin protein monomers
How do microtubules grow?
They grow at the positive and and shrink at the negative end
What are microtubules used for?
They form part of motile structures such as cilia and flagella
Crucial for cell division
Transport organelles along their length
How did scientists discover the functions of the cytoskeleton?
Direct observations of the cytoskeleton
Effects of mutations in cytoskeleton structure or function
How the cytoskeleton responded to various conditions
What are the 3 main function of the cytoskeleton?
- Structural support
- Motility
- Regulate biochemical activities
What makes the cytoskeleton good for maintaining cell shape?
Quick to dismantle and reassemble in another part of the cell
How do nutrient absorbing epithelial cells in the small intestine use cytoskeletons?
They use microfilaments to form microvilli, which increases the surface area of the cells
In the small intestine, what kind of diseases can effect the microvilli? why is this bad?
Celiac disease triggers an immune response that damages the intestines’ lining. This is bad because it prevents the absorption of some nutrients
Another main use of the microfilaments is the cell division _________ ring
contractile
Describe the Brownian ratchet
It’s a way for cells to expand
G-actin is only added to the end of a microfilament when there is space and energy (via ATP). Space is made via brown movements, which is tiny vibrations. Once space is made, the cytoskeleton can expand and change the direction or shape of the cell
Cell motility comes from the interaction of the cytoskeleton and _____
motor proteins
What can motor proteins do?
Walk along the cytoskeleton, form cross-links with transmembrane proteins, vesicles, or other cytoskeleton filaments
How do animal cells change shape to move?
microfilaments reorganize to create cellular extensions. This extension combined with the interactions of the plasma membrane (or the proteins in it) and external substrate help to move the cell
What is an example of animal cells moving?
Wound healing: fibroblast cells migrate to the site of injury to aid in tissue repair
What is phagocytosis?
The process by which a cell extension surrounds and engulfs a foreign object.