The amount of a substance that is lethal to 50 per cent of the experimental animals exposed to it. LD 50 is usually expressed as the weight of the substance per unit of body weight of the animal in order to account for weight difference among animals. A large molecule composed of a linear sequence of amino acids. This linear sequence is a protein's primary structure. Further folding from interaction between sites in the secondary structure forms the tertiary structure of the protein.
Proteins are essential to the structure and function of cells.
An industrial plant that uses a high-temperature process to separate out a pure metal, usually in a molten form, from an ore. External sites are not endorsed by the Australian Academy of Science. The Australian Foundation for Science and the Science and Technology Awareness Program of the Commonwealth Department of Industry, Science and Resources are also supporters of Nova . This topic is sponsored by the National Occupational Health and Safety Commission and the Commonwealth Department of Industry, Science and Resources .