Biology1project2 Essay Example | Topics and Well Written Essays - 750 words

Biology1project2 - Essay Example DNA molecules make individual copies of themselves by replication. Before a cell divides, each strand of genetic information makes a duplicate. During cell division the duplicates separate, so each cell has a complete set of genetic information. That single cell then divided many, many times to turn into the 50 trillion or so cells that make up a human being. Almost all of the cells in human body share the same DNA as was found in that first cell. DNA contains all of the information needed. This information is stored in the over 20,000 human genes found in almost all your cells. To get at the information, a gene must be turned on (expressed) and the information turned into something useful, a protein. Once made, that protein goes out into the cell and performs some set of specific tasks. For a cell to work, 1000s of these proteins must be made, each doing its particular job. The traits of a living thing depend on the complex mixture of interacting components inside it. Proteins do mu ch of the chemical work inside cells, so they largely determine what those traits are. But those proteins owe their existence to the DNA (deoxyribonucleic acid). DNA consists of four different sugars that interact with each other in specific ways. A much longer piece of DNA can therefore be the equivalent of different words connected to make a sentence, or gene that describes how to build a protein. And a still longer piece of DNA could contain information about when that protein should be made. The entire DNA in a cell gives us enough words and sentences to serve as a master description or blueprint for a human. Active stretches of DNA must be copied as a similar message molecule called RNA. The words in the RNA then need to be "read" to produce the proteins, which are they stretches of words made up of a different alphabet, the amino acid alphabet. "Central Dogma" of heredity--that the DNA code turns into RNA message that has the ability to organize 20