Question

select the best answer to the question and explain why.
which of these would NOT contribute to membrane bilayer asymmetry?
A. Flippase-mediated transverse motion of lipids
B. Biosynthesis and insertion of new lipids
C. Longitudinal movement of phosphatidylcholine from outer to inner leaflet

Answer 1

Best answer: C. Longitudinal movement of phosphatidylcholine from outer to inner leaflet (We will treat this as Rotational diffusion, is the movement of the lipid about its long axis.)

The lipid bilayer is a two-dimensional fluid matrix where the phospholipid molecules are able to move in a number of ways (See below figure). The lipids themselves are able to move within the bilayer to new locations. The basic types of lipid motions include lateral diffusion, transverse diffusion, rotational diffusion and trans-gauche isomerization. Lateral diffusion of the lipids is the movement of one lipid exchanging places with a neighbour in the same monolayer. Transverse diffusion is the movement of one lipid from one monolayer to the other. This motion is commonly known as "flip-flop". Rotational diffusion is the movement of the lipid about its long axis. Trans-gauche isomerization is the name associated with the intrachain motions of the lipid (ex. flexing, kink formation, etc.). The fastest motions are the trans-gauche motions. Motions can be sped up with the help of integral enzymes. This is especially true of the transverse motion; the lipid can flip faster with the help of the enzyme Flippase, which helps the hydrophilic headgroup pass quickly through the hydrophobic tail region. During Biosynthesis and insertion of new lipids, as drug concentration was increased in samples, a dramatic decrease in bilayer thickness occurs.

Thank You So Much! Please Rate this answer as you wish.