Noun. 1. axon-long nerve fiber that conducts away from the cell body of the neuron. axone. nerve fiber, nerve fibre-a threadlike extension of a nerve cell.nerve cell, neuron-a cell that is specialized to conduct nerve impulses. nerve end, nerve ending-the terminal structure of an axon that does not end at a synapse.oun. 1. axon-long nerve fiber that conducts away from the cell body of the neuron. axone. nerve fiber, nerve fibre-a threadlike extension of a nerve cell.
The genetic code is a nearly universal language that encodes directions for cells. The language uses DNA nucleotides, arranged in codons of three, to store the blueprints for amino acid chains.
RNA plays a central role in the pathway from DNA to proteins, known as the  Central Dogma  of molecular biology. An organism's genetic information is encoded as a linear sequence of bases in the cell's DNA. During the process known as transcription, a RNA copy of a segment of DNA, or messenger RNA (mRNA), is made. This strand of RNA can then be read by a ribosome to form a protein. RNAs also play important roles in protein synthesis, as will be discussed in the ribozyme section, as well as in gene regulation.