Membrane Structure and Membrane Protein Flashcards
What does the lipid bilayer provide ?
Basic structures for all cells membranes it can be easily seen as electron microscope .
What are the two main structures /function of biological membranes which the cells consists of ?
Lipid Component 50 %
Protein Component (most of the rest)
What are lipids molecules arranged as ?
Arranged as continuous double layer 5nm thick called lipid bilayer
Green -Protein
Lipids moleucles - Red /pink
What are some of the Components of the Lipid Bilayer ?
Phospholipids , Phosphoglycerides such as phosphartidelyonies
Glycolipids and cholesterol
What are all the components of the lipid bilayer ?
They are all amphiphillic they have a hydrophilic water loving or non polar and hydrophobic water fearing or polar end
Examples of a amphiphillic ?
Phosphatidylcholine is a phospholipid
Is a amphiphillic it has a hydrophilic water loving and non polar and hydrophobic water fearing or polar end
What is the most abundant membrane lipids ?
Phospholipids they have a polar head containing a phosphate group and two hydrophobic /Hydrocarbon tails.
How hydrophobic and hydrophilic molecules interact with water ?
Acetone is a polar therefore forms hydrogen bonds re and electrostatic the yellow with water molecules are also polar
2-methylpropane is a hydrophobic because it cannot form interactions with water it pushes the water molecules away.
Can the Kink in unsatured molecules affect the fluidity ?
Yess
What can distinguish major types of membrane phospholipids ?
Polar heads such as net neutral for fatty acids , (Choline)
Net negative for (Serine)
Net negative for (Amine)
What are LIpids Membranes self sealing ?
Why ?
Energetically unfavourable
Planar phospholipids with edges are exposed to water
Closed structure is stable because it avoids the exposure of hydrophobic hydrocarbon tails to water
Sealed compartments form by phospholipids bilayer
Why can amphillic molecules self assemble in aqueous media ?
These molecules form spontaneously form micelles or bilayer in water depending on shape Micelles are amilphillic molecules and move regular .
How do Lipids move within membranes fluidity ?
Fluidity
Lateral Diffusion (2um per second)
Flip Flop ( Double bonds make it difficult to pack chains together making it difficulty to freeze ) -unsaturated
Less than a month _
Flexion and Rotation
( Rapid)
Why doesn’t fusion occur ?
Because the polar head group bin water molecules that need to be displaced for bilayers of two different liposomes to fuse .
What does Fluidity Depend on ?
Its composition it has to be precisely regulated .
Temperature : Changes from liquid state to a crystal or gel Known as phase transition .
A shorter chain length reduces tendency to interact .Cis has kink preventing for it to pack together as membrane fluid at lower temperature .
Other Organism have flacuting trying to adjust to fatty acids composition of lipid bilayer to maintain a fluidity such as yeast and bacteria to avoid a decrease in bilayer to have a good terms in fluidity .
