Dichotomous Key/Start


  • 2: Membrane-bound nucleus absent; No true chromosomes, only plamids; Usually unicellular, though some cyanobacteria are multicellular; Lysosomes and peroxisomes absent; Endoplasmic reticulum, golgi apparatus, and mitochondria absent; cell size is 1 to 10 micrometers
  • 3: Membrane-bound nucleus present; Multiple chromosomes present; usually multicellular; lysosomes and peroxisomes present; Endoplasmic reticulum, golgi apparatus, and mitochondria present; cell size is 10 to 100 micrometers


  • Archaea: Cell membranes contain ether linkages; three RNA polymerases present.
  • Bacteria: Cell membranes contain ester bonds and cell wall made of peptidoglycan; one RNA polymerase


  • Animalia: Cell wall absent; Nutrients ingested; Movement possible with muscular contractions, cilia, flagella, or other organ
  • 4: Cell wall present; Nutrients absorbed, though rarely carnivorous; Very limited movement


  • Plantae: Chlorophyll present; Plant walls made of cellulose
  • Fungi: Chlorophyll absent; Plant walls made of chitin