Prokaryotes and Eukaryotes

Prokaryotes Prokaryotes: (pro- means before, and -karyote means nucleus) First type of cells to evolve Very small (size of mitochondria) Unicellular Two Types: Archaea and Eubacteria Cell Division/Reproduction: Asexual via Binary Fission

Prokaryote Shape Common shapes: rod shaped, spherical, or spiral

Prokaryote Structure  Components:  cell membrane  cell wall  ribosomes  flagella or cilia  nucleoid  cytoplasm  capsule  No membrane bound organelles

Prokaryote Genetic Information Single, circular chromosome of DNA. May also have plasmids. small pieces of DNA with additional genes

EUKARYOTES Emerged Billion years ago Characteristics: Complex structure with Nucleus and Membrane-Bound Organelles micrometeres, but up to meters in length Unicellular and Multicellular

Discussion If all cells originate from other cells, how do you think eukaryotes came about? Endosymbiotic theory - states that some eukaryotic organelles evolved from prokaryotes. For example, some of the organelles found in eukaryotes originated as prokaryotic cells that came to reside within a host cell. The host and prokaryotic cells benefited from each other and eventually resulted in this evolutionary change of eukaryote cells.

Types of Eukaryotes Unicellular (Protozoa) Protists paramecium, amoebae Fungi yeast Multicellular (Metazoa) Fungi Plants Animals Reproduction for ALL eukaryotes may be asexual or sexual.