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Discussion Starter · #1 ·
Which of the following increases membrane fluidity under normal conditions?
A. Restriction of rotational movement of proteins and lipids in the membrane
B. Binding of integral membrane proteins with cytoskeletal elements
C. Transbilayer movement of phospholipids in the plasma membrane
D. High cholesterol content of the plasma membrane
E. Binding of an antibody to a cell surface receptor
 

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Which of the following increases membrane fluidity under normal conditions?
A. Restriction of rotational movement of proteins and lipids in the membrane
B. Binding of integral membrane proteins with cytoskeletal elements
C. Transbilayer movement of phospholipids in the plasma membrane
D. High cholesterol content of the plasma membrane
E. Binding of an antibody to a cell surface receptor
i think it shud be D.
 

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Discussion Starter · #6 ·
ya its E...
explanation given by UWORLD....

Binding of an antibody to a cell surface receptor results in lateral diffusion of protein in the lipid bilayer, resulting in patching and capping. When such a divalent or multivalent ligand binds to membrane receptors present as intrinsic membrane proteins, initially there is a homogeneous pattern to the binding. Subsequently, the ligand-receptor complexes undergo patching and eventually capping on the cell surface. Rotational and lateral movements of both proteins and lipids contribute to membrane fluidity. Restriction reduces membrane fluidity. Phospholipids are capable of lateral diffusion, rapid rotation around their long axis, and flexion of their hydrocarbon (fatty acyl) tails. They undergo transbilayer movement, known as "flip-flop," between bilayers in the endoplasmic reticulum; however, this is a very rare occurrence in the plasma membrane. Other factors reduce membrane fluidity. Cholesterol at high concentrations decreases membrane fluidity by interacting with the hydrophobic regions near the polar head groups and stiffening this region of the membrane. Association or binding of integral membrane proteins with cytoskeletal elements on the interior of the cell and peripheral membrane proteins on the extracellular surface limit membrane mobility and fluidity.


can anyone pls explain this in a simpler way!!!:eek: :redcheeks;
 
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