 In this video I will distinguish between inorganic and organic chemicals. An inorganic chemical does not contain carbon. Examples that we see here include water. Only oxygen and hydrogen are elements that form part of water. There's no carbon in the water molecule. Similarly, sodium chloride is another example where there's no carbon. Any molecule that contains no carbon is an inorganic chemical. In contrast to inorganic chemicals that do not contain carbon, organic chemicals contain carbon in their molecular structure. And that carbon is usually bound to hydrogen. Lipids are non-polar organic molecules. And so lipids are hydrophobic molecules that do not dissolve in water. The example of a lipid that we see in the illustration here is a triglyceride, or neutral fat, which is the type of lipid that's found filling our fat cells, also known as adipocytes. Adipocytes store triglycerides as an energy storage molecule that can then be released and broken down in order to release energy for the cell to use for its work. Now below the lipid category, on the bottom left here we can see nucleotides. Nucleotides are monomers that will be linked together in order to form polymers known as nucleic acids. Each nucleotide monomer contains a phosphate region that has negative charges, so a nucleotide is considered an organic ion. I'd like to point out in the chemical structure of the nucleotide here, we only have carbon drawn once explicitly. However, there are many more carbon atoms in this molecule structure that have not been explicitly shown by the way that this was drawn. So I'll highlight the first carbon that you can see that was drawn, but there's also a carbon at each of the angles in this structure. And so the sugar portion of the nucleotide contains one, two, three, four, five carbons. And then if we look at the nitrogenous base, all of the angles where there's no letter written also contain carbon. And so this is what we call a line angle drawing of a chemical structure, which is common for making an illustration of an organic chemical because carbon and hydrogen are such a large portion of organic chemicals. We don't take the time to draw the C every time and we also don't draw every hydrogen in the line angle structure. Instead, every angle is assumed to be a carbon and each carbon atom is known to form four bonds. And so we can assume that we'll have hydrogens in all the possible places that are left on each carbon in order to fill out each carbon with four bonds total. Now on the top right we can see the chemical structure of an amino acid. This is a general structure for an amino acid that has an R group. Now that R group is variable. There are approximately 20 different amino acids that all have a different R group. But we can also see that there is carbon in the basic structure. There's one carbon here, another carbon here shown in this chemical structure. And there are usually several carbon atoms also found in the R side chain of an amino acid. So amino acids are certainly organic chemicals. And at the physiological pH, these amino acids will ionize where this hydrogen will come off leaving a negative charge on that oxygen. And that hydrogen will move over to this side where it will become bound to the nitrogen, giving the nitrogen a positive charge. And so amino acids in the body are typically ions until they become bound together through a dehydration synthesis reaction to form polymers. So amino acids are modemers that can be joined together to form long chains. And the long chains of amino acids are what we call polypeptides. And one or more polypeptides together form proteins. In the bottom right, we can see the last major class of organic chemicals, the carbohydrates. So all carbohydrates have the basic chemical formula of CH2O. And so for every carbon, there's two hydrogens and one oxygen in the structure of a carbohydrate. Here we see the structure of glucose, which has six carbons, 12 hydrogens, and six oxygens. So the formula of glucose is C6H12O6. Glucose is a polar organic chemical, but it is not an ion.