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).
What DNA Does. Â­DNA carrÂ­ies all of the information for your physical characteristics, which are essentially determined by proteins. So, DNA contains the instructions for making a protein.In DNA, each protein is encoded by a gene (a specific sequence of DNA nucleotides that specify how a single protein is to be made).Specifically, the order of nucleotides within a gene specifies the order and types of amino acids that must be put together to make a protein.n DNA, each protein is encoded by a gene (a specific sequence of DNA nucleotides that specify how a single protein is to be made). Specifically, the order of nucleotides within a gene specifies the order and types of amino acids that must be put together to make a protein.