TEAS 7 macromolecules: carbohydrates, lipids, proteins and nucleic acids explained

Where macromolecules sit in the TEAS 7 outline

ATI's TEAS 7 content outline lists objective S.2.4, "Describe structure and function of the basic macromolecules in a biological system," as one of five biology objectives. Biology carries 9 scored questions in total, so nine questions over five objectives works out to one or two per objective on average.

The topic still reaches further than that count suggests. Objective S.2.2 asks about the relationship between genetic material and protein structure, which is nucleic acids and proteins again, and anatomy questions on digestion assume you know what carbohydrates, fats and proteins break down into.

The four macromolecules at a glance

Carbohydrates are built from monosaccharides such as glucose, joined by glycosidic bonds. Starch in plants and glycogen in animals are the storage forms of glucose. Proteins are built from amino acids, 20 common kinds, joined by peptide bonds into polypeptide chains. They act as enzymes, carry substances, give structure and regulate cell activity.

Lipids are nonpolar and do not mix with water. Fats and oils are glycerol bonded to three fatty acids through ester linkages, phospholipids form cell membranes, and steroids such as cholesterol have four linked carbon rings. Nucleic acids are built from nucleotides, each with a five-carbon sugar, a phosphate group and a nitrogenous base, joined by phosphodiester bonds. DNA stores the genetic blueprint and RNA works mainly in protein synthesis.

How they are built and broken down

OpenStax describes the same two reactions for all four classes. Dehydration synthesis joins monomers and releases a molecule of water each time a bond forms. Hydrolysis does the reverse: water is added to split the bond. When two amino acids join, the carboxyl group of one and the amino group of the next combine and give off water.

Questions often hide this in a scenario. If the stem describes digestion or breaking a polymer into units, the answer is hydrolysis. If it describes building a longer chain from units, the answer is dehydration synthesis. A quick memory hook: hydrolysis means water splits, and dehydration means water leaves.

Details biology questions like to test

Saturated fatty acids have only single bonds between carbons and are usually solid at room temperature, while unsaturated fatty acids have one or more double bonds and stay liquid as oils. Gram for gram, fats store more energy than carbohydrates, which is why fat is the long-term store and glucose the quick one.

For nucleic acids, DNA uses deoxyribose and the base thymine, while RNA uses ribose and uracil in place of thymine. In DNA, adenine pairs with thymine and guanine with cytosine. For proteins, know the four levels of structure and that heat or acid can denature a protein, changing its shape so it stops working. Enzymes are proteins, not carbohydrates or lipids.

A two-minute self-check

Answer these from memory: what is the monomer of a protein, which bond joins two sugars, which macromolecule forms most of the cell membrane, which sugar is in RNA, and which reaction digestion uses. The answers are amino acids, a glycosidic bond, phospholipids, ribose and hydrolysis.

If you missed two or more, write the four classes as rows on one card with columns for monomer, bond, job and one example, then rebuild the card from a blank page the next day. Our TEAS science breakdown shows how this fits with the other biology and chemistry objectives.

Sources

ATI TEAS Version 7 Content Outline (PDF). Biology objectives S.2.2 and S.2.4 wording; biology has 9 scored questions (checked November 2026).

OpenStax Biology 2e, Chapter 3 Summary. Four classes of macromolecules; glycosidic bonds; starch and glycogen as glucose storage; dehydration and hydrolysis common to all; saturated vs unsaturated fatty acids.

OpenStax Biology 2e, 3.3 Lipids. Glycerol plus three fatty acids via ester linkages; solid vs liquid fats; phospholipids in membranes; steroids with four rings; fats store more energy than carbohydrates.

OpenStax Biology 2e, 3.4 Proteins. 20 common amino acids; amino, carboxyl and R groups; peptide bond releases water; enzymes are proteins; four levels of structure; denaturation.

OpenStax Biology 2e, 3.5 Nucleic Acids. DNA as genetic blueprint, RNA in protein synthesis; nucleotide parts; phosphodiester bonds; deoxyribose vs ribose; thymine vs uracil; A-T and G-C pairing.