De novo is a Latin phrase, meaning "from the new," anew, or from the beginning. De novo synthesis refers to the synthesis of complex molecules from simple molecules such as sugars or amino acids, as opposed to their being recycled after partial degradation. For example, de novo synthesis of nucleotides is an alternative to the salvage pathway. Note, "DNA polymerases cannot initiate chain synthesis de novo" (Lodish et al., 2008, Molecular Cell Biology 141.). pyrimidines (cytosine, thymine, uracil) and Purines (adenine, guanine) are not needed in the diet as they can be constructed by de novo synthesis and salvage pathways.