Mass transport in cellular systems

• Hydrophobic interaction

• Van der Waals forces

• Hydrogen bonds

1. Lipid dissolution innon-polar solvent

2. Solvent evaporation

3. Lipid rehydration

4. Formation of lipid bilayers

• Lipid types & clustering

• Headgroup functionalization

• Insertion of of non-lipid building blocks

• Differences in fatty acid arrangement

Parameter describing the freedom of protein movement and lipid constituents within the cell membrane

• Liquid disordered

• Liquid ordered

• Gel

• 
  

• 20 - 40 mol % of lipids in eukaryotic plasma membranes

• fills gaps in bilayers and lowers their permeability

• act as cellular recognition site (blood type, immune system

• can associate with specific proteins, growth factors other sugars

• are a functional group that is either part of lipid bilayers or interact with them

• Passiv: along deltaC, Diffusion

• Active: Against deltaC, Pump proteins

• Endo& Exocytosis: Vesicle fusion or generation

• SImple diffusion for gases, hydrophobic molecules, small polar molecules

• Faciliated diffusion:

  • Crossing membrane with a membrane protein

  • Protein shields molecule from hydrophobic bilayer core

• Gated facililiated diffusion

  
  

• molecules are pumped against their concentration gradient with the assistanceof membrane proteins

• Energetic uphill transport of molecules

• Molecular transport by adenosine triphosphate (ATP)-fueled pump proteins

• Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with thecell membrane

• Exocytosis describes the process of vesicles fusing with the plasma membrane to release their contentsinto the extracellular environment.

D*K/L

Reaction coefficient

Diffusion coefficient

Membrane thickness