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Biology assignment
Introduction
At a microscopic level, we are all composed of cells. Look at yourself in a mirror. What you see is about 10 trillion cells divided into about 200 different types. Our muscles are made of muscle cells, our livers of liver cells, and there are even very specialized types of cells that make the enamel for our teeth or the clear lenses in our eyes! In my assignment I have looked into how substances enter and leave cells. This research will give you a better understanding into how cells function. I will talk about the phospholipid bilayer the barrier in which substances have to pass to enter the cell, along with many other important aspects
Structure of the phospholipid bilayer
The membrane phospholipid bilaler is a major barrier that is impermeable to the usual water-soluble substances such as ions, glucose, amino acids and many others. Lipid- soluble substances such as oxygen, nitrogen and alcohols dissolve in the phospholipids and diffuse rapidly through the cell membrane as if it was not there even though water is highly insoluble in the membrane phospholipid, it is readily able to penetrate the phospholipid layer as well as pass the protein channels. The reason for this is unsure and there are many theories about why this happens.
Despite the variable compositions of biological membranes, the basic structural unit of virtually all biomembranes is the phospholipid bilayer...