Cytoskeleton Flashcards
(9 cards)
What is a cytoskeleton and what does it act as?
- 3D structure made of proteins that fills the cytoplasm.
- Acts as muscle and skeleton for movement and stability.
What are the primary types of fibres comprising the cytoskeleton?
- Actin filaments/microfilaments.
- Microtubules.
- Intermediate filaments.
How fast do organelles move and what is the fastest cell?
- When pulled along by the cytoskeleton, they cover about 5 micrometres per second.
- A white blood cell, which uses its internal cytoskeleton to crawl along, can manage speeds of micrometres per minute.
Microfilaments : protein subunit, structure, function.
Protein subunit: Actin.
Structure: Contractile fibres.
Function: Cell movement , Cell contraction, Cytokinesis.
Microtubules: protein subunit, structure, function.
Protein subunit: Tubulin.
Structure: Globular tubular proteins.
Function: Determines cell shape, tracks for moving organelles and vesicles, spindle fibres for mitosis, and also makes cilia and flagella.
Intermediate fibres: protein subunit, structure, function.
Protein subunit: Many types e.g. keratin.
Structure: Scaffold shapes.
Function: Gives mechanical shapes, anchors organelles.
How do the flagella and cilia work?
- Dyneins are motor proteins.
- One end of dynein is bound to the A microtubule.
- Using ATP, the other end reaches out to the adjacent B microtubule.
- Causes 2 adjacent microtubule doublets to slide relative to one another.
- The flagella/cilia bends.
Pseudopodia (“false feet”)
- Formed by microtubule and filament structures.
- Cell structure projects outward which is supported inside by filaments. Cytoplasm moves in forming the pseudopodium.
- Functions include locomotion and the capturing of prey.
Centrioles
- Made of microtubules.
- Contain 9 sets of triplets and no doublets in the centre.
- Comes in pairs, each organised at right angles to the other.
- Function is to form spindle fibres to move chromosomes during mitosis and meiosis.
