Endomembrane System Flashcards
What’s the endomembrane system?
Compilation of membraneous organelles locates Within the cytoplasm, evolved from mitochondria
Provides a structural divide/ provides functional diversity
What’s the plasma membrane
A boundary that separates a cell from its surroundings
What are the functions of the plasma membrane?
Compartmentalisation (provides a barrier from everything else)
Transport (has selected permeability)
Signal transduction
Intracellular junction
What’s the phospholipid bilayer?
Phospholipids are the most abundant lipid in the plasma membrane
Have hydrophobic heads and hydrophilic tails
Have receptors on the surface that act as signalling molecules
What are the functions of the membrane ?
Transport Enzyme activity Signal transduction Cell cell recognition Intercellular joining
What factors influence membrane fluidity?
Temp
Steroids (cholesterol)
What’s the cytoskeleton?
Fibrous network to which organelles are tethered
Provide structure and organisation
What proteins do the cytoskeleton consist of?
Microfilaments (actin)
Myosin (type 1 and 2)
Microtubules (tubulin)
Intermediate filaments (cytikeratins)
What do the microfilaments consist of?
2 strands of interwined actin (7nm in diameter)
Acts as a cell shaper: muscle contraction
Cytoplasmic streaming
Cell motility
What’s G actin
5nm diameter globular protein that can polymerise to form F actin which has a diameter of 7nm
F acting has 2 interwined polymer chains of G actin that form a right handed double helix with 13 actin monomers per turn
