DNA stands for Deoxyribonucleic acid. This molecule carries the genetic information used in the development / functioning of living organisms. Each molecule consists of two DNA strands wound around eachother in a double helix structure. Each strand is a ‘polynucleotide’ meaning it is made up of many individual subunits called nucleotides. Each nucleotide is made up of the sugar deoxyribose, a phosphate group and one of four nitrogen-containing bases – either cytosine (C), guanine (G), adenine (A) or thymine (T). The ordering of As, Ts, Cs and Gs is what makes up the ‘code’ of genetic information.


Genes are the basic physical and functional unit of heredity – they can be thought of as sections of DNA that code for specific things. E.g. a particular section of DNA will code (carry the information needed to make) a particular protein, while another section will code for a protein of a different type.

Igneous Rock

Rocks that crystallise via cooling from a molten state, either underground or on the Earth’s surface

Metamorphic Rock

Rocks that have been altered by heat, pressure and/or chemical action of fluids and gases.


Proteins are molecules made up of chains of amino acids. There are 20 different naturally occurring amino acids, and these can be combined in various sequences to make different proteins with different functions. Proteins have a wide range of different roles in organisms including (amongst many others!) transporting molecules around cells, catalysing various reactions and acting as structural components of various cells/tissues.

Sedimentary Rock

Rocks formed by deposition of sediment. This sediment is formed by breakdown of existing rocks, and can be transported by various processes e.g. wind, water and ice before it is deposited. The sediment accumulates and becomes compacted and cemented over time to form a sedimentary rock.