文档介绍：Schematic diagram of a typical procaryotic cell. Minimally, a procaryote posed of a cell wall and plasma membrane that surrounds its cytoplasm containing a chromosome, ribosomes, enzymes, several classes of RNA, and small molecules (precursors).
(一)细胞壁cell wall:
细胞壁的观察方法:
①质壁分离+染色
②电镜观察
G+与G-细菌cw的模式结构
★共有组分—肽聚糖
★特有组分—G+磷壁酸
Gˉ脂多糖
细胞壁是位于菌体的外层,内侧紧贴细胞膜的一层无色透明,坚韧而有弹性的结构。细胞壁约占细胞干重的10%-25%。
Electron micrograph of a G+ cell wall.
Electron micrograph of a G- cell wall.
细胞壁cell wall:
Gram Positive
Gram Negative
概念:肽聚糖是由N-乙酰胞壁酸(NAM)和N-乙酰葡糖***(NAG)以及短肽链(主要是四肽)组成的亚单位聚合而成的大分子聚合物。
(1)CW的基本骨架—肽聚糖(共有成分)
肽聚糖网格状结构
G+菌肽聚糖单体
parison of L and D amino acids. Note that while the structure is identical, it is impossible to superimpose them.
肽聚糖网格状结构