The cell body contains the which directs the manufacture of substances that a neuron needs for growth and maintenance. myelin nucleus axon dendrite

Nucleus

Explanation:

The nucleus is a part of the cell that contains the genetic material. For all currently known organisms, the genetic material is almost exclusively deoxyribonucleic acid (DNA). This molecule has a certain sequence of bases that codes for amino acids.  DNA is transcribed into RNA, another molecule that is used for protein synthesis. So, proteins are synthesized depending on the sequences of genes. Genetic information determines what proteins a cell, tissue or organism might have.

Proteins play a fundamental role in living beings, including structural, regulatory, transporter, defensive, enzymatic or contractile.  (with the exception of some antimicrobial peptides of non-ribosomal synthesis).

A neuron is a nerve cell that is specialized to transmit information throughout the body. They need proteins to grow, maintain and perform their functions. For example, there are protein structures embedded in the membrane which are electrically active that permit electrically charged ions to flow across the membrane. Also, there are structural proteins that are important for neuronal function called actin and tubulin. Actin is predominately found at the tips of axons and dendrites during neuronal development.