Why a mastectomy may be necessary. A mastectomy is mainly used as a treatment for breast cancer or to reduce the risk of breast cancer developing. Although breast cancer in men is much rarer than female breast cancer, it can also be treated with a mastectomy. Treating breast cancer.
Bacteria. The Bacteria are considered as unicellular prokaryotic organisms. Unlike eukaryotes, bacteria cells lack an organized nucleus, mitochondria, chloroplasts and other membrane bounded organelles. Bacterial cell has only a circular DNA, which does not associate with histone protein.Bacteria do not show sexual reproduction methods.nlike eukaryotes, bacteria cells lack an organized nucleus, mitochondria, chloroplasts and other membrane bounded organelles. Bacterial cell has only a circular DNA, which does not associate with histone protein. Bacteria do not show sexual reproduction methods.
Some archaea are autotrophs and others are heterotrophs. You might wonder why archaea and bacteria are divided into separate domains. After all, they are both unicellular prokaryotes. In the 1970s, a study revealed that the cellular structures of archaea are so different from bacteria they deserved their own domain.