DNA or deoxyribonucleic acid is an essential constituent of all living organisms and contains the genetic information necessary for the propagation of life. Every cell contains DNA molecules. In the case of eukaryotic cells, such as plant and animal cells, DNA molecules reside in the cell nucleus. In the case of prokaryotic cells, such as bacteria, the DNA molecule is in the cytoplasm of the cell (since there is no membrane-bound nucleus). The DNA molecule itself is composed of two complementary strands connected together (by hydrogen bonding) to produce a double helical structure. DNA contains the information necessary for the synthesis of proteins in the cell and thus contains information required for the functioning of the cell. This genetic information is passed from the parent cell to the daughter cells during cell division, with each DNA strand acting as the template for its complementary strand.
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