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cytology 1, glycolipids, epithelial cells, glycosaminoglycans - Coggle…

- - - - membrane lipid rafts and signalling
        
        traffic coordinators
        
        facilitate the efficient transmission of critical signals by organising and concentrating key receptors, enzymes and singaling proteins within specific microdomanins of the plasma membrane.
        
        these lipid micro domains enable rapid and coordinated signal trasduction, minimising delays and ensuring precise cellular responses to external stimuli.
    - - trasnport
        
        passive transport
        
        simple diffusion
        
        material move down the concentration gradient through the phospholipid bilayer
        
        O2 diffusing inside - CO2 diffusing out
        
        facilitated diffusion
        
        passage of material is aided both by the concentration gradient and by a transport protein
        
        glucose or amino acids moving from blood into cell + H2O passing through aquaporin channels
        
        active transport
        
        molecules move against concentration gradient thus they move through a transport protein but noe energy (ATP) is required
        
        Na+K+ pumps
  - - - phospholipids 1
        
        tails
        
        fatty acids chain
        
        2nd middle
        
        phosphate group
        
        1st middle
        
        glycerol
        
        head (hydrophilic)
        
        phosphatidyl- inositol
        
        phosphatidyl - ethanolamine
        
        phosphatidyl - serine
        
        phosphatidyl - choline
        
        Phospholipids 2:
        
        they are not based on GLYCEROL
        
        1st middle
        
        aminoalcohol sphingosine
        
        SPHINGOLIPIDS
        
        PHOSPHOGLYCERIDES
    - - two tyoes
        
        integral membrane proteins
        
        functions
        
        cell surface receptors
        
        adhesion molecules
        
        transporters
        
        ABC Transporters
        
        constitute a ubiquitous superfamily of integral proteins that are responsible for the ATP-powered translocation of many substrates across membranes
        
        2 more items...
        
        ion channels
        
        peripheral membrane proteins
        
        types
        
        non-covalently associated with the membrane
        
        can be on the inner or outer lead of the memebrane
    - - cholesterol
        
        functions
        
        renders the lipid bilayer less deformable and decreases its permeability
        
        prevents the crystallisation of fatty chains of phospholipids
  - - - lipids and proteins can float in the membrane via diffusion
        
        factors that affect fluiduty
        
        unsaturated fatty acids
        
        cholesterol
        
        proteins
        
        length of fatty acid chains
        
        temperature
    - - lipids, proteins and sugars are arranged asymmetrically on the inner and external side
      - phosphatidylserine resides in the cytosolic layer of the plasma membrane --> it translocates to the extraceolulare layer during programmed cell death
    - - the membrane structure is interrupted by integral proteins
    - - the membrane is permeable but with strict selections