Cytoskeleton Flashcards
Due to Abnormal Ciliary Dynein
- Symptoms include:
- Respiratory system abnormalities
- Situs Inversus
- Thoracic& abdominal organs on the wrong side of the body.
Kartagener’s Syndrome
Cell interior composed of:
- Cytoskeleton
- Cytosol
- Organelles
Cytosol often comprises more than ______% of a cell’s volume.
Site of ______
50%; protein synthesis
Elements of the Cytoskeleton
- Microfilaments (Actin, “thin filaments”) (6 types)
- Microtubules (Tubulin) (12 types)
- Intermediate filaments (31 types)
- Motor proteins. i.e. Myosins, Dynein, Kinesin.
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The most abundant protein in most eukaryotic cells
Microfilaments
Main component of microfilaments, which are double-stranded, thin, and flexible structures
Actin
Most actin molecules work together to give support and structure to the plasma membrane and are found
near the cell membrane
Microfilaments are composed _________ , and generate force by ________, causing movement of the intervening strand.
of linear polymers of actin subunits; elongation at one end of the filament coupled with shrinkage at the other
Actin structures are controlled by the
Rho family of small GTP - binding protein:
- Rho itself for contractile acto-myosin filaments (“stress fibers”)
- Rac for lamellipodia
- Cdc42 for filopodia.
Microvilli contain
actin
Microvilli
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Microtubules
- Long, hollow, cylindrical structures composed of tubulin and organized around a centrosome, an organelle usually found in the center of the cell near the cell nucleus.
- One end of each microtubule is embedded in the centrosome; the microtubule grows outward from there.
Microtubules are much more rigid than _______ molecules and have a larger diameter: _______ nanometers
They are _________ and go through a process of continuous growth and decay.
actin molecules; 25 nanometers
relatively unstable
Microtubules play key roles in:
- intracellular transport (associated with dyneins and kinesins, they transport organells like mitochondria or vesicles)
- the axoneme of cilia and flagella
- the mitotic spindle
- syntheis of the cell wall in plants
Molecules that bind to microtubules
- Colchicine (depresses MT assembly) (avidly taken up by neutrophils, which become suppressed as a treatment for gout)
- Tau (abnormal in Alzheimer’s disease)
- Motor proteins
- Dynein (moves to minus end, center)
- Kinesin (moves to plus end, outer)