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## Microorganisms ### 2.2.1. Eubacteria **Self-questioning** 1. What are bacteria and what do they do? 2. Where can we get them? Eubacteria (biology=definition): Literally means "true bacteria". They include all bacteria (except for archaea bacteria). Bacteria (singular: bacterium) are relatively s...

## Microorganisms ### 2.2.1. Eubacteria **Self-questioning** 1. What are bacteria and what do they do? 2. Where can we get them? Eubacteria (biology=definition): Literally means "true bacteria". They include all bacteria (except for archaea bacteria). Bacteria (singular: bacterium) are relatively simple, single celled (unicellular) organisms. Because their genetic material is not enclosed in a special nuclear membrane, bacterial cells are called prokaryotes (Figure 2.3). Prokaryotes include both bacteria and archaea. Millions of bacteria exist in every environment both inside and outside other organisms. The bacteria include cyanobacteria, which have bluish pigments in addition to chlorophyll that enable them to photosynthesize. Some bacteria are harmful, but most serve a useful purpose. They support many forms of plant and animal life, (Figure 2.4), and they are used in industrial and medicinal processes. Bacteria are thought to have been the first organisms to appear on earth, about 4 billion years ago. The oldest known fossils are of bacteria-like organisms. **Key words** | | Explanation | |---|---| | A. | Prokaryotes: are unicellular organisms that lack a nuclear membrane-enclosed nucleus. | | B. | Eukaryotes: are organisms whose cells have a nucleus enclosed within a nuclear envelope. | | C. | Unicellular: a unicellular organism has just one cell | | D. | Multicellular: a multicellular organism has more | **Self- Questioning** What are the common characteristics to all Bacteria? ### Biology Grade 12 **Activity 2.1** Work in small groups on the structure and function of flagella and pili in bacteria. Make a table comparing the two different structures of cells and share your ideas with the rest of the class.