Did you know?

DNA carries the information for making all of the cell's proteins. These pro­teins implement all of the functions of a living organism and determine the organism'­s characteristics. When the cell reproduces, it has to pass all of this information on to the daughter cells.

Before a cell can reproduce, it must first replicate, or make a copy of, its DNA. Where DNA replication occurs depends upon whether the cells is a prokaryote or a eukaryote (see the RNA sidebar on the previous page for more about the types of cells). DNA replication occurs in the cytoplasm of prokaryotes and in the nucleus of eukaryotes. Regardless of where DNA replication occurs, the DNA carr­ies all of the information for your physical characteristics, which are essentially determined by proteins. So, DNA contains the instructions for making a protein. In DNA, each protein is encoded by a gene (a specific sequence of DNA nucleotides that specify how a single protein is to be made). Specifically, the order of nucleotides within a gene specifies the order and types of amino acids that must be put together to make a protein.