(b) the membranes of both b cells and the cancer cells are largely composed of phospholipids. explain how, when the membranes are fused, the polar parts of the phospholipids from one cell will interact with the phospholipids from the other cell and how the nonpolar parts of the phospholipids from one cell will interact with the phospholipids from the other cell.

Explanation:

Membrane fusion is the process by which two different cells get united composing a unique membrane that englobes the content con the two original cells. The final new cell is known as heterokaryon. The cellular membrane has the capability to fuse to other membranes without losing their continuity. This is due to its fluidity, provided by the membrane dynamic and complex components.  

For membrane fusion to occur it is necessary that they recognize each other. Fusion proteins favor these processes promoting the cell recognition and the local distortion of the cell membrane. Their surfaces get together and form a lipidic structure between the adjacent membranes which continues to form a fusion pore. This pore will expand until the membranes are completely fused. Bilayer structure breaks locally allowing the outer layer to fuse by their hydrophilic heads, a process known as hemifusion. While this happens, the lipidic hydrophobic extremes of the outer layer of one of the membranes get inserted in the other membrane. After that, hydrophilic tails interact with each other and then the polar heads of the inner layer take place to fuse. Both the bilayers are now fused forming a continuous membrane.