L16- Cell structure Flashcards
what is the role of the cytoskeleton?
maintance of shape, giving structre and allowing movement
what are the 3 components of the cytoskeleton?
- actin filament
- intermediate filaments
- microtubles
what are the properties of the actin filament?
- long extremely tin and flexible fibres occurs in bundles
- each filament contains 2 chains og globular actin monors twisted together into a helical manner
what is the role of actin filament?
for movement in mucles, interacts with motor molecles. in muscle cells myosin pulls actin filaments along using ATP
What are the properties of intermedicate filaments?
they are intermedicate in size but are ropelike assemblky of fibrous polypeptides.
what is the role of intermediate filaments?
central role in maintaining the structural integrity of the cell and resisting mechanical stress.
-some support the nuclear enveope some support plasma membrane
what are the properties of microtubules?
- small hollow cylinders
- made of globular tubulin alpha and beta
- microtubules have 13 rows of tubulin dimers
what is the role of microtubules?
-support the cell, alter cell shape and serve as track for intracellular support
regulation of the microtubules are controlled by where?
microtubule organising centre (MTOC) in the centrosome
what important things are made from microtubules?
- cilia
- flagella
what is pinocytosis?
uptake of droplets of extracellular fluid in small vesicles
what are the 5 different types of intercellular junctions?
-gap junction
-desmosomes
-hemidesmosomes
-tight junction
adhere junction
what is a gap junction?
directly connects the cytoplasm of neighbouring cells permitting the exchange of small molecules.
what is a DESMOSOME?
specialised junctions for cell-tocell adhesion. Connect the intermediate filaments of neighbouring cells.
what is a hemidesomoes?
connect intermediate filaments of a cell to the basal lamina.
