Provide a 9 pages analysis while answering the following question: Practice Questions. Prepare this assignment according to the guidelines found in the APA Style Guide. An abstract is required. Regardless of the fact that the width of the boundary is only a few nanometers, the boundary is impermeable to most to a majority of molecules that are water-soluble.The bilayers are impermeable to ions and hence they allow the cells to control the level of salt concentration and also the pH by the process of pumping the ions across the membranes with the aid of proteins that are known as ion pumps. Naturally occurring bilayers are made up of phospholipids.The phospholipids are made up of a hydrophilic head and also two hydrophobic tails on each head. In situations where the phospholipids are exposed to water, they arrange themselves in a particular manner.This specific arrangement brings about hydrophobic forces. The head groups for the phospholipids often change to meet certain demands by the cells. For example, they can change. the head groups can change the chemistry of the surface of the bilayer.The proteins that are embedded in any membrane serve three major functions. They may be grouped therefore into three major groups. They include channel proteins that serve the purpose of allowing substances access into or out of the cell.In this case, the force that drives substances across the membrane is only the force of diffusion. Facilitated diffusion, on the other hand, refers to a type of passive transport whereby substances are allowed to cross membranes with the aid of essential and equally special transport proteins.Lastly, active transport refers to the method whereby substances are transported across membranes against the concentration gradient, that is, they move from a region of low concentration of the substance to a region of high concentration of the substance.3. Biological membranes are described as fluid due to the hydrophobic integral components that include lipids and membrane proteins that are known to move laterally or sideways throughout the membrane. In this sense, it means that the membrane is perceived as being fluid as compared to being a solid. Biological membranes are perceived as mosaic due to the fact that mosaics are made up of numerous parts, biological parts tend to possess different types of macromolecules such as integral proteins, phospholipids, glycolipids, cholesterol, and lipoproteins.