Saying "deoxyribonucleic acid" is a real mouthful. Luckily, you can call it DNA for short. DNA is found in all living things, including YOU! DNA is in every cell of your body and is shaped like a long, twisted ladder. The steps of this "ladder" are made of only four building blocks, called bases. These bases are known by the letters A, C, G, and T.

Pronunciation: de-oxy-ri-bo-nu-cle-ic acid
Function: makes up genes, and "junk DNA," stuff we don't yet fully understand
Length in human cell: about 3.2 billion bases
Shape: double helix, a twisted ladder shape
Discoverers of double helix: J. Watson, F. Crick, R. Franklin, and M. Wilkins.
Significance: contains the genetic information for all living things

Image credits: main image:Kelvin Chan; Kevin Chan.