Bacterias are very small single cells called micro organism, they are prokaryote they look a nucleous and membrane bound organelles
A. Characteristics of bacteria
-They are prokaryotes because they have no membrane bound organelle
-They process circular DNA
-They are unicellular organisms
B. Structure of bacteria
A bacteria cell consist of a mass of cytoplasm cell covered by a film cell wall, the cell wall is made up of protein and fatty substances. These cells wall have no cellular or chitin. It has a dense cytoplasm and vacuole is absent. The nuclear material is present.
C. Function of the different parts
- Ribosome: these are structures for the synthesis of protein
- Flagellum: they can be one or many, there are long and used for movement
- Mucus layer: it is called stime-capsid due to the presence of mucus, it protect the bacteria from being destroy y chemicals.
- Nuclear material: it comprises a large circle of DNA that may replicate faster than the cell
- Cell wall: it is made up of amino acid and polysaccharides
- The cytoplasm: it is gelly-like, it contains enzymes and other soluble material, it is the side for chemical reaction.
D. Difference between a bacteria cell and plant cell
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Bacteria cell
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Plant cell
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-His cell wall has amino acid and polysaccharide
-It nuclear material is made up of single cell chromosome and it is not surrounded by a nucleic membrane
-Food reserve stored in as glycogen
-Membrane bound organelle is absent in bacteria
-The present of slime capsule
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-It cell wall has cellulose
-It nuclear material is surrounded by nucleic membrane
-Food reserve stored in starch
-Membrane bound organelle is present
-Slime capsule absent
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E. Resemblance of bacteria cell and plant cell
-They both stored food as glycogen
-They can move (mobile or metal)
Morphology of bacteria
Bacteria has different forms and these form can used as a parameter to classify them, the morphology of bacteria ranges from a spherical shape, cocei, rat shape (bacilli), comma shape (vibrio).
Economic importance of bacteria
Bacteria are very important in life; they have both useful and harmful effect:
Useful effects:
- Bacterias help in recycling nutrients as decomposers then break down death organic matters releasing mineral into the soil, these are saprophytic bacteria
- Some bacteria are sources of anti-biotic e.g.streptomyce which produces streptomycin
- The ecoli bacteria in the colon of man breaks down roughage to produce vitamin A
- Cellulose secreting bacteria found in the stomach and in the calcum of animal help to produce cellulose which break down cellulose to glucose
- Energy production from bacteria e.g. bio gas
- Some bacteria are very useful in industry especially in fermentation process in the production of milk
- Nitrogen fixing bacteria are found in the route noddles of leguminous plants where they fixing nitrogen amino acid from which proteins are synthesized in plant
- Some bacteria are used in the treatment of sewage before the sewage is dispose
Harmful effects
- Some bacteria form food spoilage and food poison. In food poison the bacteria will secrete toxon into the food and when the food is consume the individual is infected
- Some bacteria are pathogenic (they cause disease to man), they can also cause disease to plants and animals. e.g. tetanus cause clostridium tetant
- De-netosphine bacteria convert nitrate and ammonia by process of dinitrification; this reduces fertility especially in water todyed soils.
