Biology 204 Notes
Cytoskeleton
Main Questions: What is the purpose of the cytoskeleton? What are the three main components? What is the function
of Microtubules? What are microtubules made of? What are important properties of Microtubules? What’s the purpose of
Microtubule Rescue and Catastrophe? What is a centrosome? What are centrioles? What’s unique about centrosomes
during cell division? What are motor proteins? What are motor proteins function? What are the two types of motor
proteins that use microtubules as tracks? What is the actin cytoskeleton? What is the function of actin cytoskeleton?
What are the two types of actin cytoskeleton? What is myosin? What is actin and myosin mostly used for? What is
cytokinesis? What is the spectrin tetramer? What’s the purpose of spectrin tetramer? What is the intermediate
cytoskeleton?
What is the purpose of the cytoskeleton?
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Gives cell its shape and allows the cell to organize&transport its internal components
Its dynamic and can change shapes
What are the three main components?
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Actin Filament
Microtubules
Spectrin Tetramer
What is the function of Microtubules?
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To act as tracks for motor proteins like kinesins and dynesins
What are microtubules made of?
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They are made of two types of tubulins ( protein)
What are important properties of Microtubules?
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It’s a tube
Has two different ends, plus and minus
Minus is found at centrosome
Can grow/shrink
Can only do this at plus end
What’s Microtubule Rescue and Catastrophe?
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The dynamic behavior at the end of an individual microtubule is termed 'dynamic instability'
This behavior manifests itself by periods of persistent microtubule growth interrupted by occasional switching
to rapid shrinkage (called microtubule 'catastrophe')
Then by switching back from shrinkage to growth (called microtubule 'rescue').
What is a centrosome?
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A centrosome is where centrioles are located, there is only one in a cell
They are the place where microtubules originate
Only present in animal
What are centrioles?
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Each cell has 2
What’s unique about centrosomes during cell division?
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The centrosome gets gama tubulin, and it replicates itself
It has no DNA map so it’s a mystery to why this occurs
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Microtubules act as mitotic spindles
What are motor proteins?
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A protein which moves vesicles and organelles by using the cytoskeleton as tracks
What are motor proteins function?
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They aid in transport internally in a cell
What are the two types of motor proteins that use microtubules as tracks?
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Kinesins- move cargo toward plus end
Dyneins- move cargo toward minus end
What is the actin cytoskeleton?
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Long protein structure made with actin
What is the function of actin cytoskeleton?
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To act as tracks for motor proteins
To aid in cell division
Important in muscle contraction
What are the two types of actin cytoskeleton?
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Bundles
Networks
This is dependent on location
What is myosin?
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It’s a motor protein that uses actin as a track
What is actin and myosin mostly known for?
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Muscle contraction
What is cytokinesis?
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When a contractile ring of actin and myosin form between the cleavage of a mother cell and pinch her into two
daughter cells
What is the spectrin tetramer?
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It’s a net found near the plasma membrane
What’s the purpose of spectrin tetramer?
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Connects external of the cell to internal
Outlines membrane to provide anchorage
What is the intermediate cytoskeleton?
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Size in-between actin and microtubules
Acts as framework