The Cytoskeleton Flashcards
What is the cytoskeleton?
A network of protein fibres that extends throughout the cytoplasm.
What function does the cytoskeleton have in a cell, in terms of stationary functions?
It gives mechanical support and shape to the cell, acting as scaffolding.
It also provides anchorage for many organelles and some enzymes.
What function does the cytoskeleton have in a cell, in terms of movement?
It enables the whole cell to move, as well as the organelles within the cell.
What are the three main components of the cytoskeleton?
Microtubules, actin (micro)filaments and intermediate filaments.
What are actin microfilaments?
Polymers of the soluble globular protein actin.
What is the structure of an actin microfilament?
They consist of two strands of the polymer wrapped around one another to form a helix.
What are actin microfilaments responsible for?
Cellular movement and the movement of cellular components.
What are intermediate filaments?
Fibrous protein monomers.
What is the structure of an intermediate filament?
They consist of two pairs of monomers wrapped around one another, giving them tremendous mechanical strength.
What is the structure of microtubules?
Hollow, straight rods.
Polymers of a dimer made from α-tubulin and β-tubulin.
What is the function of a microtubule?
They govern the location and movement of organelles, etc.
Where do the microtubules radiate from?
The centrosome/MOTC (MicroTubule Organising Centre)
Where is the centrosome/MOTC located?
Near the nucleus.
What does the centrosome/MOTC contain, and what is the function of these?
Centrioles - the site of microtubule synthesis.
What is the main role of spindle fibres in mitosis and meiosis?
They disassemble and form the spindle fibres - controlling the movement of chromosomes?
