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.
DNA is the molecule that encodes the genetic instructions enabling a cell to produce the thousands of proteins it typically needs. The linear sequence of the A, T, C, and G bases in what is called coding DNA determines the particular protein that a short segment of DNA, known as a gene, will encode. But in many organisms, there is much more DNA in a cell than is needed to code for all the necessary proteins. This non-coding DNA was often referred to as junk DNA because it seemed unnecessary. But in retrospect, we did not yet understand the function of these seemingly unnecessary DNA sequences. We now know that non-coding DNA can have important functions other than encoding proteins.