cytoskeleton

Question 1

what does the cytoskeleton do?

Answer 1

gives eukaryotic cells the ability to adopt a variety of shapes, organise compartments inside and interact mechanically with the environment, as well as coordinate movement

Question 2

what does the cytoskeleton consist of?

Answer 2

an intricate network of protein filaments that extends throughout the cytoplasm

Question 3

why is support extremely important in animal cells?

Answer 3

no cell wall

Question 4

what are the types of protein filaments in the cytoskeleton?

Answer 4

intermediate filaments
microtubules
actin filaments

Question 5

what is the cytoskeleton like?

Answer 5

highly dynamic (continuously reorganised)

Question 6

what happens in the cytoskeleton during mitosis?

Answer 6

when the cell divides, actin filaments are reorganised and the cell becomes spherical
the polarised microtubule array rearranges to form the mitotic spindle which is responsible for aligning and segregating the duplicated chromosomes
after chromosome segregation, the actin filaments form a contractile ring at the centre of the cell that pinches the cell in two
the two daughter cells reorganise their microtubule and actin cytoskeletons, enabling them to crawl their separate ways

Question 7

what is an example of the cytoskeleton being adaptable?

Answer 7

in neutrophils in pursuit of bacteria (cytoskeleton is rapidly disassembled and reassembled to change cell’s orientation and direction of movement)

Question 8

where are each protein filament found in epithelial cells?

Answer 8

actin in microvilli and a web below to anchor cells to each other
intermediate: anchored to other adhesive structures between cells, connecting to ECM
microtubules run vertically and provide a “highway” that directs newly synthesised components to their proper locations

Question 9

how can cytoskeleton filaments move from one end of the cell to another?

Answer 9

the filaments are disassembled to small soluble subunits which diffuse across the cell, then are reassembled back to filaments

Question 10

how are cytoskeletal filaments built and why?

Answer 10

linear strings of subunits are joined end to end and are also laterally associated with other filaments
this provides structure and adaptability

Question 11

what are the most diverse class of intermediate filaments?

Answer 11

keratin