Cellular Dynamics Flashcards
How can phospholipids move?
- Lateral diffusion
- Flexion
- Rotation
- Flip flop
What is the effect of unsaturated hydrocarbon chains in a phospholipid bilayer on the width of the bilayer?
It makes it less wide
What are lipid rafts?
Collections of proteins and lipids in membranes which have an affinity for each other which amplifies signalling events
What are the key enzymes in PIP signalling?
PI-3 Kinase
Outline the structure of bar domains
- Contain an amphipathic helix in the centre of the domain
- Helices are hydrophobic and bury themselves between phospholipids
How do bar domain recognise membrane curvature?
As the membrane becomes more curved, the domains gain affinity so proteins can engage with membranes
What size are actin filaments?
7nm
What size are intermediate filaments?
8-10nm
What size are microtubules?
25nm
How does amoeboid movement occur?
- move by squeezing out bits of cytoplasm and actin motor activity to move cell forward
- Actin pulls rear of the cell forward
How does protrusive movement occur?
- Actin polymerises at the front of the cell, pushing it forward
- Leaves behind trails of cytoplasm
What is the key role of microtubules?
To act as substrates for microtubule motor proteins, which move organelles and proteins around a cell
What occurs in apoptosis?
- Cells round up
- lose contents
- bleb furiously
This is driven by sudden activation of actin and myosin
How many steps along a microtubule does 1 ATP molecule allow?
8
