Cytoskeleton Flashcards
Role of cytoskeleton (5)
1) it provides mechanical support which helps animal cells remain its shape
2) allows movement of organelles in the cell
3) allows movement of whole cells (white blood)
4) involved in movement of chromosomes and separation of sister chromatids during mitosis
5) responsible for cytokinesis
cytoskeleton
the cytoskeleton is a network made up of 3 protein components that extend through out the cytoplasm
order of protein components in cytoskeleton in increasing diameter size
AIM
Actin micro-filaments
Intermediate filaments
Micro-tubules
microtubules origin
centrosome
a cell that passes checkpoint towards the end of G1 will undergo
chromosomal duplication
most important checkpoint
G1
smallest diameter
actin filaments
actin
involved in the
- gliding
- contraction
- cytokinesis
contraction in muscle cells with myosin
network of actin filaments= fine thread like fibers made of contractile proteins.
second diameter
Intermediate filaments
keratin
forms a lattice framework to which micro-tubules and micro-filaments interweave in
very stable and provides mechanical support for animal cells (lattice)
third biggest diameter
Microtubules
tubulin
origin - MTOC / centrosome
involved in cell division and movement of cell
micro-tubules assemble and disassemble to act as spindle fibers which are very active during cell division.
provides a framework to which organelles could attach to
the dynamic nature of the cytoskeleton
it is constantly changing to provide support and movement in cell. Micro-tubules and micro-filaments assemble and disassemble (controlled by MTOC)
Importance of remodeling of the cytoskeleton (4)
1) during mitosis, micro-tubules from the spindle fibers which are very active during cell division in the movement of chromosomes and separation of sister chromatids.
2) assemble and disassemble to function as spindle fibers
3) micro-tubules pinch a cell during division of cytoplasm = cytokinesis
4) during phases in between divisions, the MTOC / centrosome must produce micro-tubules to make part of the cytoskeleton
DNA Damage
p53
- apoptosis
- cell cycle arrest
- DNA repair
Phosphates and Kinase before details
removal or addition of a phosphate causes REVERSIBLE CONFORMATIONAL CHANGE
Cooperativty suggest that
haemoglobin subunits transmit information to others
example of kinases and their roles (2)
proteinkinases
- act on and modify specific proteins
- they transmit signals and control complex processes in a cell
