1. Bacteria Created by:
2. Linnaean Hierarchy Domain
5. Systematics Scientists use a variety of ways to classify bacteria:
Where they live
Depend on oxygen
Source of carbon
Gram-positive and gram-negative
6. Classify Divided into three major groups:
Thermoacidophiles –live in highly acidic and hot environments.
Halophiles- live in highly saline environments.
Methanogens –produce methane, they live in the intestines of animals and such harsh places as undersea hydrothermal vents.
7. CLASSIFICATION Split up into 3 groups based on their response to gaseous oxygen
Aerobic—thrive in the presence of oxygen and require it to survive
Anaerobic—cannot endure gaseous oxygen
Facultative anaerobes—prefer growing in the presence of oxygen, but can grow without it
8. CLASSIFICATION Classified by how they obtain their energy
Heterotrophs—derive energy from breaking down complex organic compounds that they must take in from the environment
Grow within another living cell and use the nutrients of the host cell
Autotrophs—fix carbon dioxide to make their own food
Use light energy or oxidation of nitrogen, sulfur, or other elements
9. Classification Classified based on shape
Largest of the 3 types and the easiest to identify
10. CLASSIFICATION First classification scheme was developed by Hans Christian Gram using the Gram stain
Separates bacteria based on the structural characteristics of their cell walls
Gracilicutes - Gram negative staining bacteria with a second cell membrane
Firmicutes - Gram positive staining bacteria with a thick peptidoglycan wall
Mollicutes - Gram negative staining bacteria with no cell wall or second membrane
Mendosicutes - atypically staining strains now known to belong to the Archaea
11. Key Characteristics in classifying bacteria:
photosynthetic or nonphotosynthetic
motile or nonmotile
Unicellular, colony-forming or filamentous
formation of spores or division by transverse binary fission
12. BODY capsule, the cell wall, the cell membrane, cytoplasm
No intracellular organelles (no mitochondria and chloroplasts)
Pili—hollow, hair like structures made of protein allow bacteria to attach to other cells
Flagella—long appendages which rotate by means of a “motor”
average most species of bacteria have diameters of 0.5 to 2.0 microns
Contain plasmids, small loops of DNA, that can be transmitted from one cell to another
This makes bacteria adaptable
Biologists can insert new genes into bacteria easily b/c of plasmids
14. Where they live They are found nearly everywhere
Prokaryotic cells and fossils have been found in almost every conceivable environment on the earth
hot sulfur springs to beneath the ocean floor and within larger cells
They hold all the records for living in the coldest, hottest, most acidic and most highly pressurized environments.
floating around in clouds
miles down on the sea floor
at temperatures greater than 100 C
Never find one bacteria on its own. They tend to live together in clumps, chains or planes
15. Obtain Food Prokaryotes use 4 major nutritional modes to obtain food. These modes are:
Photoautotrophs: these use CO2 as a carbon source, and light for energy. e.g., photosynthesis
Photoheterotrophs: these use light as an energy source but must ingest pre-made organic compounds. This mode is very rare.
Chemoautotrophs: These use CO2 as a carbon source, but obtain their energy from inorganic molecules such as hydrogen sulfide.
Chemoheterotrophs: These obtain both their energy and carbon from organic compounds. We are chemoheterotrophs.
16. Growth and Reproduction asexual reproduction (one parent) binary fission
Inherit identical copy of their parent’s genes
Have the ability to evolve and change their genetic material
Three techniques of reproduction (genetic transfer) exhibited by prokaryotes include:
(a) transformation - genes are taken up from the surrounding environment.
(b) conjugation - genes are transferred directly from one prokaryote to another.
(c) transduction - genes are transferred by viruses.
17. Important roles Decomposers:
Organic carbon, in the form of dead and rotting organisms, would quickly deplete the carbon dioxide in the atmosphere if not for the activity of decomposers
organisms die & the carbon contained in their tissues becomes unavailable for most other living things. Decomposition is the breakdown of these organisms, and the release of nutrients back into the environment.
18. Important roles Plants rely on nitrogen from the soil for their health and growth, and cannot acquire it from the gaseous nitrogen in the atmosphere.
The primary way in which nitrogen becomes available to them is through nitrogen fixation by bacteria
19. Important Roles decomposition of dead organisms,
symbiotic relationships (such as that between nitrogen-fixing bacteria and plant roots)
Many prokaryotes can “fix” nitrogen. This means they can convert atmospheric nitrogen gas (N2) into ammonia, a form useable by other bacteria and plants. This process is called nitrogen fixation.
Many animals are completely dependent on bacteria to digest their food for them, particularly herbivores, large vertebrates like cows and sheep, to small invertebrates like termites all are dependant on bacteria
some bacteria also play an important role in trapping the suns energy so that it can be used by living organisms
20. Impact making soil
degrading pollutants such as oil and plastics
fermented foods such as cheese, pickles, soy sauce, sauerkraut, vinegar, wine, and yogurt.
genetic engineering improvements in agricultural crops
commercial production of pharmaceuticals
Any cycle or system you look at has bacteria playing a crucial supportive role in it somewhere. Bacteria are an essential in the maintenance of these flows of energy and nutrients throughout our world. Without them the whole ecosystem would collapse.
Most of these bacteria live within us, harmlessly going about their short lives without causing us any problems at all. some in fact may even be beneficial
21. Cons of Bacteria Diseases caused by bacteria:
Some bacteria attack us in a manner that is not immediately painful in fact the pain may not be apparent for years. The primary example of this is tooth decay
22. For Your Pleasure First bacteria was observed by Anton Van Leeuwenhoek in 1674
Oldest bacteria fossil record is 3.5 billion years old
It is possible for bacteria to reproduce as often as every 20 minutes
They are the most abundant of all organisms
evolution of the prokaryotic cell has been fairly dormant over its two billion year lifespan.
23. For Your Pleasure Cnt’d… About 5000 different kinds of prokaryotes are currently recognized
during the year 2000, bacterial diseases likely killed 5 million people which accounts for 10% of the 52 million human deaths occurring on average every year
billions of individual bacteria are living in and on most of us most of the time.