Question: who said that all living things are made of cells

title: Cell theory
text: Prokaryotes : Prokaryotes are relatively small cells surrounded by the plasma membrane , with a characteristic cell wall that may differ in composition depending on the particular organism . Prokaryotes lack a nucleus ( although they do have circular or linear DNA ) and other membrane - bound organelles ( though they do contain ribosomes ) . The protoplasm of a prokaryote contains the chromosomal region that appears as fibrous deposits under the microscope , and the cytoplasm . Bacteria and Archaea are the two domains of prokaryotes . Eukaryotes : Eukaryotic cells are also surrounded by the plasma membrane , but on the other hand , they have distinct nuclei bound by a nuclear membrane or envelope . Eukaryotic cells also contain membrane - bound organelles , such as ( mitochondria , chloroplasts , lysosomes , rough and smooth endoplasmic reticulum , vacuoles ) . In addition , they possess organized chromosomes which store genetic material .