Because A, G, C, and T appear in the DNA, these molecules are called DNA-bases; A, G, C, and U are called RNA-bases. Uracil and thymine are identical except that uracil lacks the 5' methyl group. Adenine and guanine belong to the double-ringed class of molecules called purines (abbreviated as R).
Definition of decalcomania. 1  1 : the art or process of transferring pictures and designs from specially prepared paper (as to glass) 2  2 : decal.
To understand how stimuli become sensations, we will consider three attributes common to all the senses: transduction, sensory adaptation, and thresholds. Transduction is the process by which sense organs convert energy into a stream of neural impulses that are sent to the brain. For example, light entering the eye stimulates specialized neurons, called receptors, which respond by converting their excitation into a nerve impulse, which is sent to the brain for processing.