What is the monomer unit of actin microfilaments?
G-actin
F-actin
M-actin
Actin 1
What facilitates the polymerisation of G-actin to F-actin?
ATP hydrolysis
GTP hydrolysis
Phosphorylation by protein kinase
Actin polymerase enzyme
In what orientation are actin monomers composed in f-actin?
Head to tail
Head to head
Tail to tail
Actin microfilaments are described as polar whereby monomers will be added to one end at a faster rate than the other
What are the functions of the actin microfilaments? Check all that apply
Muscle contraction
Mechanical support e.g. in microvilli
Maintenance of cell shape
Cell movement
Movement of cargo within cell
Cilia formation
Non-muscle cells can contain actin and myosin networks. The interactions between filaments in these networks facilitates process within cells such as cytokinesis.
Lamellipodia are extensions of the cytoplasm containing networks. They are generated by the rapid growth of actin filaments at the pole closest to the . This produces which causes the cytoplasm to protrude outwards. The tip of each lamellipodium interacts with the ECM via protein. filaments within the cell faciliate contraction that aids movement.
The structure of intermediate filaments is dynamic.
Intermediate filament monomers join in pairs to form helical twisted around one another. Then, two dimers combine to form a . Tetramers then link in a formation longitudinally to form a bundle of monomers forming the filament.
Tubulin monomers are heterodimers of a-tubulin and B-tubulin
What facilitates the depolymerisation of microtubules to tubulin monomers?
Phosphorylation
Methylation
Tubulin hydrolase
Microtubules are dynamic structures whereby the positive end refers to where construction occurs more rapidly than destruction
What are the functions of the microtubules? Check all that apply
Resit compression
Spindle formation
Form cilia and flagella
Organise organelles
Whole-cell movement
What is a microtubule organisation centre (MTOC)?
A structure from which microtubules extend
A protein which organises microtubule polymerisation
A protein which gathers protofilaments at their centres to bundle them into microtubules
The centrosome is a type of Microtubule Organisation Centre. A centrosome contains a pair of . A centriole consists of stable fused . Centrosomes form at the of cells. microtubules attach the centrosome to the .
What is the name given to the protein that develops around the centromere of each chromosome to which spindle fibres attach?
Kinetochore
Kinetosome
Kinetoprotein
Which protein associated with microtubules moves towards the positive end of the microtubule at the cell periphery?
Kinesin
Dynein
Which protein associated with microtubules moves towards the negative end of the microtubule at the nucleus?
When proteins move cargo throughout the cell, they do so via the of the cytoskeleton. These proteins are composed of double which allow roation. Each 'head' can attach to the microtubule when bound to . When ATP is hydrolysed, there is a where the angle of the head changes and the cargo moves along the microtubule. Then, the second head binds and the process repeats.
What is the structure of a cilium?
Ring of 9 microtubule doublets with a single microtubule doublet in the centre
Ring of 8 microtubule doublets with 2 microtubule doublets in the centre
Ring of 9 microtubule doublets
Ring of 9 microtubule triplets
What is the name given to the structure of the MTOC found near the cell membrane that provides a template for cilia assembly?
Basal body
Basal centromere
Kinetic body
All cells have a single primary cilium. This cilium is not and is thought to cell signalling pathways. It must be before mitosis can occur.
Which cell junctions form junctions between cells connected to the cytoskeleton?
Desmosomes
Gap junctions
Hemidesmosomes
Focal adhesions
Tight junctions
