【共享】分子生物基础知识（图文）

下面是一些分子生物学基础知识，有助于某些实验的理解。

E. coli is a Gram-negative, rod-shaped bacterium about 2.5 micrometers long that contains flagella and a genome of 4,639,221 base pairs encoding at least 4000 genes。 The K12 strain was first isolated in 1921 from the stool of a malaria patient and it has been maintained in laboratory stocks as a pure strain for the last 75 years. E. coli K12 was the bacterial strain of choice in biochemistry labs because it was easy to grow and amenable to metabolic studies. Like all Gram-negative bacteria, E. coli have no nuclear membrane and the chromosome is a large circular duplex molecular with a membrane attachment site and a single origin of replication. E. coli cells can support the replication of DNA plasmids, many of which encode antibiotic-resistance genes.

Scanning electron micrograph of E. coli cells.

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