Notes

Biological macromolecule, A large, organic molecule such as carbohydrates, lipids, proteins, and nucleic acids.
Monomer, A molecule that is a building block for larger molecules (polymers). For example, an amino acid acts as the building blocks for proteins.
Polymer, A large molecule made of repeating subunits (monomers). For example, a carbohydrate is a polymer that is made of repeating monosaccharides.

Carbohydrates, Monosaccharides (simple sugars), Provide cells with quick/short-term energy, source of dietary fiber Glucose, sucrose, starch, cellulose, chitin
Lipids, Fatty acids and glycerol, Provide cells with long-term energy, make up biological membranes Fats, phospholipids, waxes, oils, grease, steroids
Proteins, Amino acids, Provide cell structure, send chemical signals, speed up chemical reactions, etc Keratin (found in hair and nails), hormones, enzymes, antibodies
Nucleic acids, Nucleotides, Store and pass on genetic information DNA, RNA

Describing macromolecules as “large” is relative. We refer to them as “macro” because they are large compared to other, smaller molecules. However, this does not mean that they are large enough to view with the naked eye. Even a large protein, like hemoglobin, is still a million times smaller than a grain of rice!

Not all fats and carbohydrates are “bad.” Information about different kinds of diets can be confusing and may lead someone to believe that all fats or all carbohydrates are unhealthy. This simply isn’t the case. Fats and carbohydrates are actually essential for cellular function!

pH The measure of the hydrogen ion (H+) concentration in a solution
Acid Solution with a higher concentration of hydrogen ions than pure water
Base Solution with a lower concentration of hydrogen ions than pure water

Acids are not always dangerous. Acids sometimes have a bad reputation for being dangerous, but there are plenty of acidic substances that are useful (and even tasty!). For example, orange juice and coffee are acidic substances. In addition, though there are a few acids that you want to avoid handling (ex: hydrofluoric acid), don’t be fooled: strong bases can be damaging as well.

stronger base. It can be a little confusing, but the lower the pH of a substance is, the stronger of an acid it is. Sometimes it is more helpful to think that the further away from neutral a substance is, the stronger it is in either the acidic or basic direction.

Acids and bases are not only important in chemistry. Although you may go into more detail learning about them in your chemistry class, acids and bases are extremely important to living things! In fact, most enzymes work best at a specific pH. For example, the enzyme pepsin is necessary for the digestion of proteins in the stomach, but it only functions at a very low pH. Therefore, it is important for the body to maintain an acidic environment in the stomach to make sure food gets digested well.