Basic Biology Course To Understanding Biotechnology

Living things are made of cells and every cell contains a molecule of DNA. The DNA itself is made up of four bases: guanine (G), adenine (A), thymine (T) and cytosine (C). These bases connect with one another to form very long strands that fold and bend in the famous double helix shape (find picture). The fact that the sequences of bases in the DNA of individuals from the same given species are roughly similar to one another make it possible to tell that a cat is a cat and a horse is a horse. The different sizes, shapes and colours of cats, for example, is explained by the many small differences in their DNA even though the sequences are similar.

DNA molecules interact with the chemicals in the cell's environment and then do a lot of work on behalf of the organism in which the cell is situated. These interactions regulate many of the organisms life functions such as its growth and its reproduction. In sexually reproducing organisms, parts of the DNA from each parent recombine to form a new molecule. This new molecule then interacts with its environment to form an organism with a unique mix of characteristics from each parent.

The fact that differences at the level of a whole organism are related to small differences in the DNA sequence is extremely important for food production. Farmers want plants that are well suited to a given climate , i.e. that do not bloom too early, or mature too late, for examples, or that are especially tasty, that are visually attractive, or even that are easy to process or ship. The list of desirable characteristics is long, and many of these characteristics are related to DNA in very complex ways.

Scientists have developed techniques that allow them to remove genes from plant and animal tissue and to make many copies of the given sequence in a laboratory. Scientists can change organisms and obtain products in ways not thought possible just forty years ago with recombinant DNA technology which encompasses tools and techniques for genetically manipulating organisms ranging from bacteria and fungi, to plants and animals. These techniques go from reinserting a gene into the DNA of an organism, to inserting genes from one species into the DNA of an organism of an entirely different species. For example, a tomato plant could tolerate sub-freezing temperatures after a gene tolerant of sub-freezing temperatures has been copied and inserted in the tomato.