from what is the smallest living thing?

• presence of DNA and proteins are a prerequisite for considering bacteria alive.
• "Parvovirus DNA can be less than 5000 nucleotides long"
• "Viroids are small circular single strands of RNA that lack a protein coat." "Their RNA can be as short as 248 nucleotides long (80,000 molecular weight)."
• .."Prion proteins, which are about 30,000 molecular weight.."

Notes:
A single atom of carbon-12 has a mass of 12 u exactly, by definition. Wikipedia


A nucleotide is composed of a nucleobase (nitrogenous base), a five-carbon sugar (either ribose or 2'-deoxyribose), and one to three phosphate groups. Wikipedia