Exam 1 Part 6 Flashcards
functions of membranes in cells
- barrier/boundary (protection)
- area for localization of proteins
- areas of localized communication
- import/export
- movement
animal membrane makeup
40% lipids
50% proteins
10% carbohydrates
how membranes change fluidity
change saturation and unsaturation of lipid tails with dB
formation of sealed compartments
planar phospholipid bilayer with edges exposed to water
self-sealable because of energies
membrane movements
lateral movements, rotations, bending
flip-flops are rare without enzymes
fluidity of membrane depends upon
- bonds
- FA tail lenght (shorter, more fluid, longer, more viscious)
- amount of cholesterol
cholesterol
can fit in between unsaturated area which can make it more viscious
lipid rafts
localization sites
keeps stuff all in the same area
pack stuff that need to be in one area together
makes membrane asymmetric
synthesis of membranes…
start in endoplasmic reticulum
scramblase
moves random phospholipids from one ER membrane side to the other
Flippase
transfers specific phospholipids from Golgi membrane side to cytosolic side
-leads to asymmetry
membrane protein types
transporters and channels
anchors
receptors
enzymes
transporters and channels
allow things to pass through membrane like glucose, ions, a.a.,metabolites
anchors
anchors things like actin to a specific area
receptors
receive hormones, neurotransmitters on the surface of the membrane