How DNA Works | HowStuffWorks

• The deoxyribonucleic acid (DNA) is a pattern made up of four different parts called nucleotides.
• Each nucleotide consists of a sugar (deoxyribose) bound on one side to a phosphate group and bound on the other side to a nitrogenous base.
• There are two classes of nitrogen bases called purines (double-ringed structures) and pyrimidines (single-ringed structures).
• The DNA has four bases: Adenine, Cytosine, Guanine, and Thymine.
• The DNA is often visualized like a spiral staircase -- the double helix.

• The DNA is a long molecule that is about a millimeter long.
• While humans have 46 chromosomes, plants and animals are complex organisms which can contain 50 to 100 thousand genes on many different chromosomes.
• The DNA of such organisms are twisted around bead-shaped proteins called histones. They are coiled tightly to form chromosomes that are located in the nucleus of the cell.
• Every time a cell reproduces the DNA gets copied and distributed to each offspring.

• For the replication process to occur, it is highly dependent on whether the cells are prokaryotic or if it's a eukaryote. Regardless of where it happens, the DNA replication process is the same.
• The DNA is shaped like a double helix that runs in opposite directions in which is able to unzip down the middles so that it may serve as a template for the other side.
• The small area where it can unzip is called a replication fork, where it moves down the entire length of the molecule.

• The DNA carries the instructions on making protein, which is basically the determinant for our physical characteristics.
• A protein is basically made up of a lot of amino acids and it has many functions from aiding digestion to making antibodies for the immune system.
• Protein usually differs from one another, and the particular sequence causes the chain of the amino acids together, this then is encoded in the DNA.

If we equate DNA as the master blueprint, we could then say that a protein is the house. There are many involved in this process such as the messenger RNA which is the working copy of the DNA, the cytoplasm, amino acids, ribosomes, and the transfer RNA molecules.

Basically speaking, proteins are made inside cells. The instructions of how to make proteins are held inside the DNA molecules and the two major stages in making a protein are called transcription and translation.