When biologists classify life at a high level, life is determined to be either Eukaryotic or Prokaryotic. While eukaryotes compose all multicellular organisms such as animals, plants and fungi, prokaryotes are single cell organisms such as bacteria and archaea. The largest differentiator between eukaryotes and prokaryotes is the structure of its cellular components. Eukaryotic cells contain membrane bound organelles such as Mitochondria, a Golgi apparatus, and most importantly; a Nucleus. Due to the fact that eukaryotes don’t contain a nucleus, the genetic information contained in eukaryotic cells is bundled up in a corner of the cell forming a nucleolus. The DNA in prokaryotic cells exists as only one long circular strand while eukaryotic DNA exists in many separate strands. Even though both types of cells contain ribosomes, the ribosomes are noticeably larger in eukaryotes. The membrane on eukaryotes is composed of phospholipids while protein-sugars form the membrane in prokaryotes. Additionally, eukaryotic cells are generally larger and more complex than simple prokaryotic cells. Although some eukaryotic life such as a plant cell forms a cell wall, all prokaryotic cells form a cell wall that is vastly more complex. Eukaryotic cells contain a cytoskeleton and divide through the process of mitoses, prokaryotes lack a cytoskeleton and divide through binary fusion. Eukaryotic and prokaryotic cells differ greatly but together they decide how life is organized.
References:
http://www.diffen.com/difference/Eukaryotic_Cell_vs_Prokaryotic_Cell