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.
Because of its biological importance, and the fact that it constitutes less than 2% of the genome, sequencing of the exome was the first major milepost of the Human Genome Project. The number of protein-coding genes within the human genome remains a subject of active investigation. A 2012 analysis of the human genome based on in vitro gene expression in multiple cell lines identified 20,687 protein-coding genes.