上游充通大￥ Shanghai Jiao Tong University 国 Bacteria contain one long circular DNA- chromosome.细菌的类核包含一条环状的DNA (染色体) The DNA can be 1mm long ©The cell is usually2-3μm long Membrane Wall DNA Chen Feng,Shanghai Jiao Tong UniversityShanghai Jiao Tong University Chen Feng, Shanghai Jiao Tong University Bacteria contain one long circular DNA￾chromosome. 细菌的类核包含一条环状的DNA (染色体) The DNA can be 1mm long The cell is usually 2-3m long