(2)bacterial size Most of the bacterial cell diameter is about 0.5mm,and the length is about 0.5~5 mm.However,reported the diameter of the smallest nanobacteria is less than 0.05 mm.The largest coccus is Thiomargarita namibia, whose diameter size is up to 100-750 um
（2）bacterial size Most of the bacterial cell diameter is about 0.5mm, and the length is about 0.5~5 mm. However, reported the diameter of the smallest nanobacteria is less than 0.05 mm. The largest coccus is Thiomargarita namibia， whose diameter size is up to 100-750 μm
2.Cell structure model 细胞壁 鞭毛 construction 内含物 细胞膜 菌毛 of bacterial cell 核区 间 性菌毛 芽孢 微英膜 细胞质 荚膜 糖被 内含物 粘液层 般构造 特殊构造
model construction of bacterial cell 2. Cell structure
(1)cell wall Conception of cell wall:Cell wall is the most outside layer of cells which is thick and tenacious.Its main ingredient is peptidoglycan.It has many functions such as fixed shape,protecting cells and so on. The functions of cell wall Ofix cell shape, enhance its mechanical strength and protect cells from outside injury;2It is necessary for cell growth, division and flagellum movement 3It can block enzyme protein,antibiotics,and other harmful substances into cells OIt can give specific antigen and pathogenicity to bacteria (e.g.,toxins).It is closely related to the sensitivity of bacteria to antibiotics and bacteriovirus
(1) cell wall Conception of cell wall：Cell wall is the most outside layer of cells which is thick and tenacious. Its main ingredient is peptidoglycan. It has many functions such as fixed shape, protecting cells and so on. The functions of cell wall ：①fix cell shape, enhance its mechanical strength , and protect cells from outside injury；②It is necessary for cell growth, division and flagellum movement ；③It can block enzyme protein ,antibiotics, and other harmful substances into cells ；④It can give specific antigen and pathogenicity to bacteria (e.g., toxins). It is closely related to the sensitivity of bacteria to antibiotics and bacteriovirus
Types of cell wall cell wall of gram-positive bacteria cell wall of gram-negative bacteria 革兰氏阳性细菌(G 革兰氏阴性细菌(G) 外膜蛋白 孔蛋白 肽聚糖 壁磷壁酸 脂多糖 膜磷壁酸 磷脂 〉外膜 脂蛋白 周质空间 周质空间 肽聚糖 细胞质膜 细胞质膜 细胞内部 Structure of cell wall about gram-positive bacteria and gram-negative bacteria
Structure of cell wall about gram-positive bacteria and gram-negative bacteria Types of cell wall：cell wall of gram-positive bacteria cell wall of gram-negative bacteria
1.Cell wall structure of gram-positive bacteria characteristic:thickness of cell wall is big between 20~80 nm. Chemical composition is simple,which contains 90 percent peptidoglycan and 10 percent Lipoteichoic acid
1.Cell wall structure of gram-positive bacteria characteristic：thickness of cell wall is big between 20~80 nm. Chemical composition is simple, which contains 90 percent peptidoglycan and 10 percent Lipoteichoic acid