UNWANTED PROTEINS
The nucleus of most human cells contains a person’s unique DNA It is arranged in 23 chains of chromosomes and there are 3 million pairs of 4 nucleotides. 98 percent of the DNA encodes the directions for turning a fertilized egg into a being. Two percent encode 20,000 genes, pairs of nucleotides that can range in size from as a few hundred paired nucleotides long to as many as a length of more than a million nucleotides. Each gene, using messenger RNA, directs the cell to make a certain protein. Proteins are “ molecules that perform an array of functions.” Some, for example, catalyze metabolic reactions; others provide structure or transport molecules from one location to another. Biologically proteins are sequences of amino acids that have folded into a specific structure. “All genes are not expressed in each cell: different sets of genes are active in different types of cells. Nerve cells express genes different from those expre...