Water: The Polar Molecule
The cell has to have boundaries that keep all of its' components close together. But it has to be constructed in such a way so that it could regulate what and when materials can come in and leave the cell. It must also be able to survive a watery environment. Water is an interesting chemical in that it shapes a cell. Water is a polar molecule. This means that there are portions of the molecule that have a positive charge and portions that have a negative charge. Water consists of 2 hydrogen atoms that are covalently bound to an oxygen atom. In nature, hydrogen must fill its outer electron orbit by finding a single electron and incorporating it into its own structure. The oxygen atom wants to bring in two electrons to fill its outer energy level. Because covalent bonding allows for electrons between atoms to be shared, this allows hydrogen and oxygen to come together to form a molecule called water. Now, because the sharing between these atoms is unequal, the oxygen atom will have the hydrogens' electrons longer than the hydrogen atoms will have the oxygens' electrons. This unequal sharing causes oxygen to be slightly negative and the hydrogens to be slightly positive. These charges is what causes water to be polar.