1
Q
What is the cytoskeleton ?
A
- Present in the cytoplasm which consists of cytosol, organelles and the cytoskeleton.
- Dynamic meaning its constantly moving, allowing it to respond to changes and carry out its function.
- only present in eukaryotic cells
- network of fibres
2
Q
Made up of 3 protein fibres
A
- microfilaments
- microtubules
- intermediate fibres
3
Q
Roles of the cytoskeleton
A
- whole cell support
- mechanical strength
- formation/ movement of cilia
- cell movement eg, exocytosis, phagocytosis and cytokinesis
- movement of organelles
- movement of genetic material
4
Q
structure of microfilaments
A
- small solid strands
- about 7 nm in diameter
- fibres are contractile
- formed by the protein actin
5
Q
microfilaments functions
A
- actin important in muscle contraction
- responsible for cell movement and cell contraction during cytokinesis
- involved in phagocytosis
6
Q
Micro tubules structure
A
- tiny protein cylinders, straight and hollow
- around 18-30 nm in diameter
- Globular tubulin proteins polymerise to from tubes which form scaffold like structures which determines the shape of the cell
7
Q
Micro tubules function
A
- acts as tracks for the movement of organelles, including vesicles, around the cell.
- motor proteins walk vesicles along microtubules
- spindle fibres are composed of microtubules
- centrioles, made of micro tubules
- cilia and undulipodia are composed of microtubules
8
Q
Micro tubules function movement
A
- cellular movement is accomplished by cilia and undulipodia
9
Q
What are cilia ?
A
- cilia are hair like structures,
- can beat in synchrony, causing movement.
- found in lining of trachea and tubes of female oviduct
- have a 9+ 2 arrangement
10
Q
What are undulipodia
A
- whip like appendages that undulate to move cells.
- longer than cilia
- similar internal structure to microtubules
- found on sperm cells
- have a 9+2 arrangement
11
Q
intermediate filaments structure and function
A
- 10 nm in diameter
- give mechanical strength to cells to help maintain their integrity
12
Q
What are motor proteins
A
- molecular motors that use the cytoskeleton to move along the cytoplasm of the cell.
13
Q
What is myosin
A
- a cytoskeletal motor protein for micro filimants
- allows muscle contraction when interacts with actin
14
Q
What is dynein ?
A
- cytoskeleton protein
- allows cilia/ undulipodia movement when interacts with tubulin
15
Q
Defective dynein causes
A
- male infertility
- leads to respiratory tract ans sinus problems
16
Q
what is kinesin?
A
- motor protein
- moves vesicles when interacts with tubulin
Biology Module 2
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