DNA

DNA, short for Deoxyribose nucleic acid, is the chemical that is found inside the nucleus of the cells of all organisms. It carries the vital genetic codes that dictate how an organism will grow and shape. Each DNA molecule consists of two long strands that are wrapped around each other. Because of this, the DNA structure resembles a double spiral "staircase" or a helix.
     Below: An actual microscope photo of a DNA strand.

Each rung of the DNA ladder is composed of two substances, known as bases, which lock together. All in all, there are four different types of bases, and together they create four different kinds of rungs. The exact DNA sequencing of these rungs makes up a cell’s chemical information. This DNA information is vital since it shapes the cell’s development and regulates every single detail of how a cell should work. DNA contains chemical information known as genes. These genes are individual instructions in the code that tells the body’s cells how to produce new proteins.

 DNA replicates before cell division so that a full set of DNA information is given to each new cell. During cell division, DNA molecules tighten up to form chromosomes. These chromosomes undergo a series of events and eventually replicate so that each new cell will have the same genetic information found in the originals, and the newly-formed cells will function the same way as those of the parent cells.