A polymer made up of amino acids joined by peptide bonds. The amino acids present and the order in which they occur vary from one protein to another.
A list of often difficult or specialised words with their definitions.
A short piece of DNA which is responsible for the inheritance of a particular characteristic. It codes for the production of a specific protein. Genes occupy a fixed position, called a locus, on a particular DNA molecule.
Reusable protein molecules which act as biological catalysts, changing the rate of chemical reactions in the body without being affected themselves
Deoxyribonucleic acid. This is the molecule which contains the genetic code. It coils up tightly inside chromosomes. DNA is a double helix made from two strands which are joined together by pairs of bases.
A chromosome is like a packet of coiled up DNA. Humans have 23 pairs of chromosomes. They are in the nucleus of every human cell.
A gene is a length of DNA forming part of a chromosome. In humans there are about 20,000-25,000 different genes arranged among the 23 pairs of chromosomes.
Genes contain the code to make proteins, which are involved in the development and functioning of body organs and systems. Proteins are essential to life and have many functions in the body, for example, as enzymes, regulators and structural molecules.
Genes are also the units of heredity by which characteristics, such as eye colour and blood group, are passed from one generation to the next.
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