membrane strcuture

Question 1

what are the components of the membrane

Answer 1

• phospholipid - creates the belayer
• cholesterol - maintains fluidity
• protein
• carbohydrates - binds to lipids dn protein and is used for signalling and communication

Question 2

what are the 3 types of lipid

Answer 2

phosphoglycerides - they have a polar head (phosphate) and 2 fatty acid tails - what attaches these two are 3 glycero hydroxyl groups

sphingolipids - less abundant, form a backbone, has a polar phosphoryl choline head and glycolipids have a carbohydrate group

sterols - smaller than other membrane lipids, single polar head attached to steroid ring and short non polar tail

Question 3

what affects the membrane fluidity

Answer 3

saturated or unsaturated fatty acid tails
- when unsaturated they create a disruptive formation, and if they are shorter there is les interaction between the tails so it is more fluid

temperature
-low temp = fluidity is low, warm temp= more energy

membrane cholesterol
- they act as temperature buffers. i cold temps they keep the phospholipids apart increasing the fluidity and in hot temps keeping them close reducing the fluidity

Question 4

membrane proteins

Answer 4

• peripheral proteins
• integral proteins
• membrane bound proteins
• transport proteins = channels or carrier
• glycoproteins

these structures have a high concerntration of cholesterol and glycosphingolipids, these are more tightly ordered and packed, and they float freely in te membrane bi layer

Question 5

what are the functions of the proteins in the membrane

Answer 5

• junctions - to connect two cells together
• enzymes - fixing
• transport - facilitated and active transport
• recognition - markers for cell identification
• anchorage - attachment points
  transduction - function ad receptors for peptide hormones

Question 6

how does movement in the cell membrane occur

Answer 6

• a catalyst called flipase - moves substances from outer to inner
• a catalyst called floppase - moves inner to outer
• a catalyst called scramblase when it occurs at the same time, inn and out

Question 7

drug transportation

Answer 7

• liposomes - these have the same lipid bilayer where they have an aqueous core and dugs that are hydrophilic are placed in the aqueous core and drugs that are hydrophobic are placed in the lipid bilayer
• micelles - this structure has a monolayer, it has an internal lipophillic zone for hydrophobic dugs