Cell structure cell membrane Flashcards
what are the functions of the plasma membrane?
selective permeability, structural maintenance, transport and cell signalling
the heads on a phospholipid are…
negatively charged and hydrophilic
the tails on a phospholipid are…
non-polar tail and hydrophobic
As the phospholipid molecule has hydrophobic and hydrophilic portions, it is said to be…
amphipathic
the fluidity in cell membranes is governed by…
the “kinks” in the phospholipid tails, push adjacent phospholipid molecules away
high-temperature causes…
increased fluidity- phospholipids become less rigid and allow more movement
low-temperature causes…
decreased fluidity- membrane is more solid and closer together
fatty acid tails interact via…
Van der Waal’s
cholesterol is…
the major sterol in mammalian membranes, it is amphipathic
the roles of cholesterol are…
- it makes lipid bilayer less deformable
- it decreases its permeability to small water-soluble molecules
- maintains fluidity
disruption in bilayer may cause…
phospholipids to ‘flip-flop’- if broken it easily fixes itself
membrane carbohydrates are…
generally short and branching sugars attached to proteins
membrane proteins are…
embedded in the fluid matrix of the lipid bilayer
integral proteins…
are present through the membrane
peripheral proteins…
associated with the phospholipid head groups or other integral proteins
