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Flashcards

Biomembranes

Jacob Coe FoM Year 1 University - Medicine English 26 cards

What is Wilson's Disease?

Cards in this deck (26)

  1. 1What are the 4 functions of membranes?1. Forms the boundaries of cells.
    2. Compartmentalisation.
    3. Formation of concentration gradients.
    4. Cellular communication.
  2. 2Why are membranes classed as amphipathic?Contain hydrophilic heads & hydrophobic tails.
  3. 3What ways do the hydrophilic heads & the hydrophobic tails point in a membrane?Hydrophilic heads face outwards.
    Hydrophobic tails face inwards.
  4. 42 of the -OH groups are linked to fatty acids. What is special about the 3rd?The 3rd -OH group is phosphorylated.
  5. 5The phosphate group is further linked to a small polar alcohol head, either: Choline Serine Inositol Ethanolamine What are the phosphorylated versions of these?Phosphatidylcholine
    Phosphatidylserine
    Phosphatidylinositol
    Phosphatidylethanolamine
  6. 6Where are lipid droplets stored in adipocytes?In the cytoplasm.
  7. 7How are lipid droplets stored in the cytoplasm?1. A lens is formed - triglycerides collect in the bilayer of the ER in adipocytes.
    2. The lens stabilises & allows for membrane deformation.
    3. Membrane undergoes vectorial deformation; membrane bulges.
    4. The membrane envelops the triglyceride mass.
    5. Junction maturation releases the newly compartmentalised mass of triglycerides.
  8. 8What enzymes maintain the asymmetry of the cytosolic & exoplasmic faces of the membrane in terms of lipid composition?Flippase/Floppase enzymes - aid the 'flip-flop' of lipids.
  9. 9What is the significance pf a phosphatidylserine lipid present on the exoplasmic face of the membrane?Marks the cell for destruction - possibly due to cell damage or the end of it's cell cycle.
  10. 10Cardiolipin is a lipid present in the membranes of which organelles?Mitochondria.
  11. 11Where are sphingolipids highly concentrated?The myelin sheath surrounding neuronal axons.
  12. 12In which 3 directions can phospholipids move?1. Lateral movement.
    2. Rotation.
    3. Flexion.
  13. 13What is the effect of C=C bonds in the membrane?Enable the fluidity of the membrane - so phospholipids can be mobile.
  14. 14List 2 reasons as to why phospholipids must be able to move.1. Essential for the functioning of membrane proteins which must be able to move to operate.
    2. Adjacent proteins may need to communicate & interact with one another.
  15. 15Lipids can interact with 2 types of receptor. Namely...GPCRs & Nuclear receptors
  16. 16Name examples of lipid signalling molecules.Sphingosine-1-phosphate
    Diacylglycerol (DAG)
    Inositol phosphate (PIPs)
    Prostaglandins
    Steroid hormones
  17. 17What are lipid rafts?The interaction between large, saturated tails of sphingolipids with cholesterol.
  18. 18What is the effect of lipid rafts?Stabilise the liquid crystalline phase.
  19. 19What are 3 functions of lipid rafts?1. Cholesterol transport.
    2. Endocytosis.
    3. Signal transduction.
  20. 20Compare & contrast simple & facilitated diffusion.Simple diffusion: Transports small, non-polar molecules (O2, CO2) & uncharged polar molecules (urea & ethanol). High conc. to a low conc. Passive - NO ATP.
    Facilitated diffusion: Larger, polar molecules (amino acids & sugars). High conc. to low conc. Passive - NO ATP. Requires channel/carrier proteins.
  21. 21What are the 3 types of transporter & their functions.Uniport - single substrate across the membrane.
    Symport - 2 different substrates across the membrane in the same direction.
    Antiport - 2 different substrates across the membrane in opposite directions.
  22. 22Define primary active transport.Transport of molecules against their concentration gradient using ATP.
  23. 23Define secondary active transport.The movement of a molecule against its concentration gradient harnessing the energy produced by the active transport of another molecule.
  24. 24How does the Sodium-Glucose symport function using secondary active transport?The symporter uses the energy obtained from the influx of sodium to facilitate the transport of glucose into the cell.
  25. 25What is Menke's Disease?X-linked disorder.
    Copper transporting ATPase is defective.
    Copper enters intestinal cells but goes no further.
    COPPER DEFICIENCY.
  26. 26What is Wilson's Disease?Copper ATPase enzymes is dysfunctional.
    Failure to excrete copper from the liver into bile.
    TOXIC ACCUMULATION.
    Kayser-Fleischer rings.    What is Wilson's Disease?

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University - Medicine FoM Year 1 (Physiology FoM) Flashcards on Biomembranes, created by Jacob Coe on 14/12/2021.
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Jacob Coe
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