Organic Chemistry Molecules made up of carbon and hydrogen are called organic compounds. Oxygen and Nitrogen are common atoms found in organic compounds as well. In many molecules, atoms are arranged in special clusters called functional groups.

Common Functional Groups

Macromolecules A macromolecule is a large molecule made up of smaller subunits often with many functional groups. The four major groups of macromolecules are: carbohydrates, lipids, proteins and nucleic acids.

Carbohydrates Contain carbon, hydrogen and oxygen. Used mostly for energy. Produced by plants in photosynthesis. Broken down into energy by animals in cellular respiration.

Carbohydrates Monosaccharides are “simple sugars” and have a sweet taste. The most common one is glucose C 6 H 12 O 6. Disaccharides occur when two monosaccharides join together (i.e. glucose + fructose = sucrose, which is table sugar).

Carbohydrates Long chains of simple sugars combine to form polysaccharides. These are called “complex carbohydrates”. They are used for energy storage like starch in plants and glycogen in animals OR used for structural support like cellulose in plant cell walls and chitin in insect exoskeletons (contact lenses and stitches as well).

Good Sources of Carbohydrates

Lipids Made up of C, H and O as well, but with more H. They store more energy than carbohydrates, but harder to get the energy out of. Four classes of lipids: oils and fats, waxes, phospholipids and steroids.

Fats and Oils Each of these is known as a triglyceride, contain three fatty acids attached to a glycerol molecule.

Fats and Oils If the fatty acids are straight, they are known as saturated fatty acids and the substance is a fat (i.e. lard, butter, animal fat). Can lead to coronary artery disease if over eaten.

Fats and Oils If they are bent, they are called unsaturated fatty acids and the substance is an oil (peanut oil, canola oil, plant oils).

Phospholipids Main component of cell membranes. Head part is hydrophilic (loves water) while tail is hydrophobic (hates water). They are like fats and oils, but have a phosphate group instead of one of the fatty acids.

Steroids Made up of four fused carbon rings. All are derivatives of cholesterol. Cholesterol is a big reason cell membranes are flexible and fluid. All our sex hormones are natural steroids.

Waxes They are used by animals and plants as waterproofing agents. Basically they are steroids with long side chains coming off of them. Examples: beeswax, cutin on leaves…

Good Sources of Lipids

Proteins Most diverse and important molecules in living organisms. Made up of small subunits called amino acids that are held together by peptide bonds. Protein making is called protein synthesis and happens on ribosomes.

Proteins Enzymes are special proteins that are used to speed up chemical reactions without getting used up themselves. If an enzyme loses its shape, it is said to be denatured and does not work anymore. This happens if the temperature or pH changes.

Good Sources of Protein

Nucleic Acids Made up of nucleotides that contain a sugar, a phosphate group and a nitrogen base. The two main nucleic acids are DNA and RNA. DNA contains hereditary information, whereas RNA is used in protein making.

Nucleic Acids DNA has one of four nitrogen bases in its nucleotides, Adenine, Thymine, Cytosine and Guanine. It is a double-stranded molecule where A binds to T and C binds to G. RNA is a single strand and has Uracil instead of Thymine.

Homework 1) Where in your digestive system would the macromolecules we have discussed be broken down? 2) What other things do we need in our diets besides the macromolecules discussed today? 3) From Austin Powers, Fat Bastard says he went on the Atkins Diet in which “Carbs are the enemy”! Is this a safe thing to do, eliminate carbohydrates? Why or why not?