Cytoskeleton, Cell Movement And Cell Division Flashcards
What is a cytoskeleton and what are their functions?
Filamentous proteins arranged within a cell.
Maintain cell shape
Position organelles
Movement of cell (motility) and vesicles
Roles in cell division (anaphase and telophase)
Discuss microfilament structures and functions.
Microfilament is an actin fibrous protein (F-actin formed from G-actin proteins)
- resists tension
- vesicular endocytosis and exocytosis
- cell contractions such as cleavage furrows and amoeboid movement
- fibroblasts in CT and Osteoblasts and osteoclasts activity in bone (motor proteins found here)
- Myosin motor protein - ATP dependent
Which end are actin subunits being added to the microfilament?
Positive end
Describe the appearances of each end of the microfilament.
Barbed - positive end
Pointed - negative end
What is the function of integrin?
Anchor positive end.
What makes microtubule?
Tubulin dimers - alpha and beta
List functions of microtubule.
Division of cell - in anaphase
Resists compression
Vesicular movement
What is special about microtubule structure which allows cell division?
Easily assembled and disassembled so separase acts on tubulin at the kinetichore to digests tubulin poly chains into subunits which are being added to the non kinetochore mitotic spindle.
What is an anterograde?
The positive end of microtubule
Describe the directions of kinesin and dynein act on the microtubule.
Kinesin towards positive terminal
Dynein towards negative terminal
Give examples of intermediate filaments.
Keratin - nails, hair, hoofs, horns, skin
Nuclear Latin - nuclear lamellae
Neurofilament
Desmin and Vimentin
What is the function of intermediate filament?
Resists tension
Maintain cell shape
Position of nucleus and organelles within the cell
Why is intermediate filament so tough?
Monomer (subunits) join together to form a supercoiled structure which rolls into a supercoiled sheet further strengthening the structure, hence it is not readily disassembled.
