LYCOS RETRIEVER 
Bacteria
built 212 days ago
Bacteria are set apart from all other organisims because their cells lack nuclei (they are prokaryotic). All other organisims are eukaryotic, meaning that their cells contain nuclei. Because of this fundamental difference, all prokaryotes have long been grouped together in one Kingdom, Monera. However, strong new evidence indicates that there are actually two distinct groups of prokaryotes: Bacteria (or Eubacteria) and Archaea (or Archaebacteria). These two groups diverged from one another near the time of the origin of life! The eukaryotes almost certainly evolved from the eubacteria shortly thereafter.
Source:
Bacteria are single-cell organisms and most of them must find foods such as sugars, proteins and vitamins to live. The blue-green bacteria (some times called blue-green algae) have chlorophyll and can make their own food from light energy + carbon dioxide. Some other bacteria have red chlorophylls and can use light and carbon dioxide to make the sugars they need. Like all living things bacteria require mineral salts such as magnesium, calcium, iron, and others. Some bacteria are able to obtain the energy they need by oxidizing iron or sulfur. Some bacteria need sugars, vitamins, aminoacids, and other growth factors already digested and ready to use.
Source:
Bacteria have different shapes. Bacteria that have an approximately round shape are referred to as cocci (singular: coccus). This name is derived from a Latinized Greek word kokkos, meaning a berry. Cocci are not necessarily perfectly spherical, and may be quite markedly deformed. Cells of Streptococcus pneumoniae generally occur in pairs, known as diplococci, that are flattened to appear like small lancets. For this reason they are sometimes referred to as lanceolate diplococci.
Source:
Bacteria have flagella, shown in Figure 6, although the bacterial flagellum has a different microtubule structure than the flagella of eukaryotes. Cell walls of bacteria contain the peptidoglycan instead of the cellulose found in cell walls of plants and some algae. Ribosomes are the structures in cells where proteins are assembled. Bacterial ribosomes have different sized ribosomal subunits than do eukaryotes.
Source:
Bacteria alter the soil environment to the extent that the soil environment will favor certain plant communities over others. Before plants can become established on fresh sediments, the bacterial community must establish first, starting with photosynthetic bacteria. These fix atmospheric nitrogen and carbon, produce organic matter, and immobilize enough nitrogen and other nutrients to initiate nitrogen cycling processes in the young soil. Then, early successional plant species can grow. As the plant community is established, different types of organic matter enter the soil and change the type of food available to bacteria. In turn, the altered bacterial community changes soil structure and the environment for plants.
Source:
Bacteria are both harmful and useful to the environment and animals, including humans. The role of bacteria in disease and infection is important. Some bacteria act as pathogens and cause tetanus, typhoid fever, pneumonia, syphilis, cholera, food-borne illness, leprosy, and tuberculosis(TB). Sepsis, a systemic infectious syndrome characterized by shock and massive vasodilation, or localized infection, can be caused by bacteria such as Streptococcus, Staphylococcus, or many gram-negative bacteria. Some bacterial infections can spread throughout the host's body and become systemic. In plants, bacteria cause leaf spot, fireblight, and wilts.
Source:
MORE ABOUT
Bacteria