一、 真核生物与原核生物的比较 Characteristic Procaryotic Eucaryotic Size of cell Typically 0.2-2.0 um in diameter Typically 10-100 um in diameter Nucleus No nuclear membrane or nucleoli True nucleus,consisting of nuclear membrane an nucleoli Membrane-enclosed Absent Present;examples include lysosomes,Golgi organelles complex,endoplasmic reticulum,mitochondri and chloroplasts Flagella Consist of two protein building blocks Complex;consist of multiple microtubules Glycocalyx Present as a capsule or slime layer Present in some cells that lack a cell wall Cell wall Usually present:chemically complex When present,chemically simple (typical bacterial cell wall includes peptidoglycan) Plasma membrane No carbohydrates and generally lacks sterols Sterols and carbohydrates that serve as receptors present Cytoplasm Ribosomes No cytoskeleton or cytoplasmic streaming Cytoskeleton;cytoplasmic streaming Smaller size (70S) Chromosome (DNA) Larger size (80S);smaller size (70S)in organelles Single circular chromosome;lacks histones Multiple linear chromosomes with histones arrangement Cell division Binary fission Mitosis Sexual reproduction No meiosis;transfer of DNA fragments only Involves meiosis 一、真核生物与原核生物的比较