| MOLECULE | Basic structural unit of a chemical compound (8) |
| CELLWALL | Basic structural unit of a plant |
| CELL | Smallest structural unit of a plant (4) |
| CELLS | Smallest structural units of a plant (5) |
| TAUTOMER | Either of two or more isomers of a chemical compound existing together in equilibrium and interconvertible by migration of atoms and bonds (8) |
| CATALYST | A substance that increases the rate of a chemical reaction without itself suffering any permanent chemical change (8) |
| TCELL | Type of basic structural unit that develops in the thymus and is known as a lymphocyte (1,4) |
| TRICYCLIC | Of a chemical compound, having three interconnected rings of atoms in its molecular structure (9) |
| PTOMAINE | Cat in agony given drug, a chemical compound (8) |
| SYNTHESIS | Production of a chemical compound (9) |
| ISOMER | Variant of a chemical compound (6) |
| HYDRATE | Hate dry version of a chemical compound (7) |
| STABLE | Of a chemical compound, unlikely to undergo processes such as decomposition or radioactive decay (6) |
| DRYCLEAN | Problem-laden cry of a chemical wash (3,5) |
| BIOCIDAL | (Of a chemical) inimical to living things |
| FLUORIDE | A chemical compound added to drinking water supplies and toothpaste to prevent tooth decay in children |
| ATOM | Basic unit of a chemical element (4) |
| MATTER | A gas, liquid, solid or other basic structural component of the universe with a mass and volume; the subject of speech, thought, writing etc; a thing of consequence; or, a concern (6) |
| NEPHRON | Basic structural and functional unit of the kidney (7) |
| ISOTOPE | Each of two or more forms of a chemical element whose nuclei contain equal numbers of protons but different numbers of neutrons (7) |
