1. Prokaryotic World

2. The Three Domains EukaryaArchaeaBacteria Kingdoms: Animalia Plantae Fungi Protista Kingdoms: Animalia Plantae Fungi Protista “Extremophiles” Bacteria Cyanobacteria Bacteria Cyanobacteria Eukaryotic: cells have a nucleus Eukaryotic: cells have a nucleus Prokaryotic: cells have no nucleus Prokaryotic: cells have no nucleus

3. Prokaryotic cells

4. Bacterial structure Bacteria have no nucleus, but do have: a cell membrane a cell wall a capsule flagellae or cillia Bacteria have no nucleus, but do have: a cell membrane a cell wall a capsule flagellae or cillia

5. Bacterial Structure Bacteria come in three common shapes: Coccus (spherical) Bacillus (rod-shaped) Spirillus (spiral- shaped) Bacteria come in three common shapes: Coccus (spherical) Bacillus (rod-shaped) Spirillus (spiral- shaped)

6. Motility Some bacteria are motile and can move by means of a flagella. A simple “wheel and axle” arrangement of proteins forms the base of the flagellum. Some bacteria are motile and can move by means of a flagella. A simple “wheel and axle” arrangement of proteins forms the base of the flagellum.

7. Reproduction Bacteria reproduce by binary fission (simple cell division). However, they can also exchange genetic information by trading plasmids (DNA rings) across conjugation bridges. Bacteria reproduce by binary fission (simple cell division). However, they can also exchange genetic information by trading plasmids (DNA rings) across conjugation bridges.

8. Ecological roles Bacteria play a wide range of roles in the ecology. Many are decay organisms, breaking down dead material and releasing inorganic compounds such as nitrogen compounds or carbon dioxide. Some are symbiotic organisms that live in animal digestive systems. Some are disease-causing organisms. Bacteria play a wide range of roles in the ecology. Many are decay organisms, breaking down dead material and releasing inorganic compounds such as nitrogen compounds or carbon dioxide. Some are symbiotic organisms that live in animal digestive systems. Some are disease-causing organisms.

9. Ecological Roles Nitrogen-fixing bacteria are associated the the roots of certain plants. These bacteria convert nitrogen gas into compounds that plants can absorb.

10. Escherischia coli E. coli is a well- known gut bacteria. Like all prokaryotes, it has no nucleus and no membrane-bound organelles, but is highly adaptable. E. coli is a well- known gut bacteria. Like all prokaryotes, it has no nucleus and no membrane-bound organelles, but is highly adaptable.

11. E. coli The “hot dog” shape is a typical “bacillius” form. Normally, E. coli is a part of our intestinal flora. Out of place, however, it can cause serious infections. The “hot dog” shape is a typical “bacillius” form. Normally, E. coli is a part of our intestinal flora. Out of place, however, it can cause serious infections.

12. E. coli In this photo, you can see the bacterial DNA coiled up in the center of the organism. Bacterial DNA forms one long loop rather than strands. Small loops (“plasmids”) can be shared between bacteria. In this photo, you can see the bacterial DNA coiled up in the center of the organism. Bacterial DNA forms one long loop rather than strands. Small loops (“plasmids”) can be shared between bacteria.

13. Cyanobacteria These are photsynthetic bacteria that gather in long strands. Cyanobacteria were probably the first photosynthetic organisms on the planet. These are photsynthetic bacteria that gather in long strands. Cyanobacteria were probably the first photosynthetic organisms on the planet.