The Cytoskeleton

What is the monomer unit of actin microfilaments?

What facilitates the polymerisation of G-actin to F-actin?

In what orientation are actin monomers composed in f-actin?

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

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 [blank_start]actin[blank_end] networks. They are generated by the rapid growth of actin filaments at the pole closest to the [blank_start]membrane[blank_end]. This produces [blank_start]force[blank_end] which causes the cytoplasm to protrude outwards. The tip of each lamellipodium interacts with the ECM via [blank_start]integrin[blank_end] protein. [blank_start]Myosin[blank_end] 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 [blank_start]dimers[blank_end] twisted around one another. Then, two dimers combine to form a [blank_start]tetramer[blank_end]. Tetramers then link in a [blank_start]staggered[blank_end] 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?

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

What is a microtubule organisation centre (MTOC)?

The centrosome is a type of Microtubule Organisation Centre. A centrosome contains a pair of [blank_start]centrioles[blank_end]. A centriole consists of stable fused [blank_start]microtubules[blank_end]. Centrosomes form at the [blank_start]poles[blank_end] of cells. [blank_start]Aster[blank_end] microtubules attach the centrosome to the [blank_start]cell membrane[blank_end].

What is the name given to the protein that develops around the centromere of each chromosome to which spindle fibres attach?

Which protein associated with microtubules moves towards the positive end of the microtubule at the cell periphery?

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 [blank_start]microtubules[blank_end] of the cytoskeleton. These proteins are composed of double [blank_start]helices[blank_end] which allow roation. Each 'head' can attach to the microtubule when bound to [blank_start]ATP[blank_end]. When ATP is hydrolysed, there is a [blank_start]power stroke[blank_end] 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?

What is the name given to the structure of the MTOC found near the cell membrane that provides a template for cilia assembly?

All cells have a single primary cilium. This cilium is not [blank_start]motile[blank_end] and is thought to [blank_start]conduct[blank_end] cell signalling pathways. It must be [blank_start]disassembled[blank_end] before mitosis can occur.

Which cell junctions form junctions between cells connected to the cytoskeleton?