adenine

(symbol: A) n. a purine compound present in the nucleotides of living organisms. It is one of the four bases in DNA and RNA that constitute the genetic code, the others being cytosine, guanine, and thymine or uracil.

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

November 16th 2024

simple eye

the type of eye found in most vertebrates and some invertebrates. It consists of a single focusing element, which may be a thickening of the exoskeleton (in an arthropod), a pinhole in the surface of the eye (in a mollusk), or a crystalline lens (in a vertebrate), plus one or more photosensitive cells. Compare compound eye.