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.
The protists are single-celled eukaryotic microrganisms, as mentioned earlier. Examples are amoebas, diatoms, algae and protozoa. These can be a danger to human and animal health, as certain protists can cause diseases, such as malaria and sleeping sickness.hey reproduce by first copying their DNA and than performing cell division. Bacteria also lack membrane-bound organelles, such as mitochondria, the cell structures involved in energy metabolism. Bacterial cells are so small that scientists measure them in units called micrometers (Âµm), a millionth of a meter.