Principles of Membranes Flashcards
What are the components of the endomembrane system?
Nucleus/nuclear membrane Endoplasmic Reticulum Golgi Apparatus Plasma Membrane Lysosomes
What are lysosomal storage diseases?
Diseases where there is an accumulation of sphingolipids in the lysosome
What does a cherry red spot in the eye indicate?
Tay-Sachs disease
What are the symptoms of Tay-Sachs disease?
Progressively destroys neurons in the brain and spinal cord
Evident at 3-6 months
Development slows, muscles used for movement weaken
Eventually seizures, vision and hearing loss, paralysis
Cherry red spot!
What diseases result from defects in peroxisomes?
X-linked adrenoleukodystrophy (failure to export long chain fatty acids)
Zellweger syndrome (peroxisomal biogenesis disorder)
What do peroxisomes do?
Beta-oxidation of cellular lipids - degrade hydrocarbon chain 2 carbon units at a time to yield acetyl molecules that are transported into the cytosol
Synthesis of certain glycerolipids
What does the presence of spherocytes in the blood indicate?
A form of hemolytic anemia (e.g. Hereditary Spherocytosis)
What are glycerophospholipids?
Phosphate head and gylcerol groups + hydrophobic tail
What are sphingolipids?
Phospholipids derived from spingosine rather than glycerol, but otherwise have a similar structure to glycerophospholipids.
Do peripheral membrane proteins have to be attached to the membrane?
No as long as it is close to/associated with the membrane (e.g. attached to an integral membrane protein)
What makes up the skeletal network of RBCs?
Alpha and Beta spectrin fibers
What protein connects alpha and beta spectrin to the PM?
Ankyrin (peripheral membrane protein) which then binds to Bands 3 (integral MP) and 4.2 (peripheral)
What is unique about atypical pneumonia/walking pneumonia?
Often found in older people (40-50 yrs)
What bacterium causes Walking pneumonia? How does it work?
Mycoplasma pneumoniae extract cholesterol from the PM, negatively affecting membrane fluidity and ability to expel mucus (membrane becomes so fluid, cilia are limp and useless).
Describe membrane fluidity.
Biological membranes are highly dynamic allowing lateral movement of lipids and proteins.
Lipids can rotate about the central axis (flip -flop in trans)
