Appetizer
In a previous lesson participants learned that genes contain coded information. The coded information in a single gene normally provides the organism with the “blueprint” to make a single protein. The information for proteins is contained in DNA in four chemical units or bases, termed A, C, G and T. Information in DNA is copied into the complementary bases A, C, G and U in messenger RNA (“U” substitutes for “T” in RNA). The bases in RNA are then read by the cell machinery in sets of three, called a codon, that specify one of 20 amino acids. Strings of amino acids make proteins and together all proteins give the organism its characteristics.
Proteins are chemicals that each accomplish a task. Certain specialized proteins, called enzymes, speed up reactions in the cell - sometimes making them perform a task a million times faster. Some proteins are used to give the organism its shape, while others give it energy to perform work. For example, in plants, some proteins direct the shape and size of leaves; others determine these characteristics for the fruits, flowers and seeds, like their carbohydrate and starch content. Other proteins help the plant capture energy from the sun and directly turn it into food for the plant and indirectly for humans who eat plants or parts of plants.
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