Question

For the following question, please answer in essay format( a page and half long minimum)( if hand written please print legibly and be clear about which part of the question are answering, in complete sentences, with as much detail as possible. Thanks!

What is the chemical composition of the eukaryotic cell membrane? Describe the fluid mosaic model of the plasma membrane in detail, including the phenomenon of membrane asymmetry and how it is maintained. How can the membrane be modified to make it more fluid, or more rigid? How can plasma membrane components be removed in order to study their chemical structures? What movements are possible for these membrane components, and what restrictions are there on such movements?

Answer 1

ANSWER -

The eukaryotic cell membrane is made up of bilayer of phospholipids in which the proteins and cholestrol are embedded. the proteins are of two types , one which are present in between the phospholipid and other are the ones which are present at periphery, called as integral and peripheral proteins. along with these there are presence of pores present inthe plasma membrane which are responsbile for the transfer of ions from inside and outside the cell.

membrane assymetry means the two phospholipid bilayers have differnt composition which make them assymtericlal in nature, this asymmerty is necessary as it hleps in regulation of various transportation processes in the cell. under physiological condition, the membrane is maintained through the activation of the aminophospholipid translocase and floppase and incativation through scramblase proteins. also there is presence of another protein called as flippase.

to make the membrane more fluid, it is necessary that there is more movemnt of the lipids presnt in the bilayer, for that, the lipids are heated up and the more the thermal energy more will be the movemnt and more will be the rearrangemnt in the lipid bilayer and thus making the bilayer more fluid.

plasma membrane components can be removed with the help of bile salts like glycocholate and taurocholate and no cell lysis occurs in this process.

if we talk about the lipid movemnt within bilayer, then we have proteins like flippase and floppase which help in the movemnt of lipids either on the same bilayer or in between the two bilayers. and if we talk about the movemnt across the membrane, we have active and passive transport consisiting of symport and antiport mechanisms to aid the movemnt.

this is the basic description of the cell membrane and its composition