degeneration. deterioration; change from a higher to a lower form, especially change of tissue to a lower or less functionally active form. When there is chemical change of the tissue itself it is true degeneration; when the change consists in the deposit of abnormal matter in the tissues, it is infiltration.apetoretinal degeneration degeneration of the pigmented layer of the retina. transneuronal degeneration atrophy of certain neurons after interruption of afferent axons or death of other neurons to which they send their efferent output.
There are four different DNA nucleotides, each defined by a specific nitrogenous base: adenine (often abbreviated A in science writing), thymine (abbreviated T), guanine (abbreviated G), and cytosine (abbreviated C) (Figure 2).
Nucleotides are the building blocks of the DNA and RNA used as genetic material. Nucleotides also are used for cell signaling and to transport energy throughout cells. You may be asked to name the three parts of a nucleotide and explain how they are connected or bonded to each other.nswer: Both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are made up of nucleotides which consist of three parts: 1  Nitrogenous Base. 2  Purines and pyrimidines are the two categories of nitrogenous bases.