BACTERIA

1. The bacterial cell wall is made up of — Mucopeptide or peptidoglycon or Murein.

2. There are some bacteria which lacks cell wall — Protoplasts (gram +ve), Spheroplast(gram –ve) & L-form.

3. The common plasmid of E. coli which have been extensively exploited in the. field of Genetic engineering is — PBR322.

4. The term plasmid was used for extrogenomic DNA segment by — Lederberg (1952).

5. The plasmid which imparts drug resistance to the organism - R. — factor.

6. The bacterial cytoplasm contains few vacuoles, which grant buoyancy to a bacterial cell.

7. The sulphur containing bacteria is — Beggiatoa.

8. The Nitrifying bacteria are — Nitrosomonas & Nitrobacter.

9. The bacterium used for retting of fibre of jute, hemp & flax — Clostridium butyricum & C. felsineum.

10. The bacterias capable of decomposing some of the hazardous pesticides eg. DDT, 2-4D, — Flavobacterium & Acetobacter aerogenes.

11. Some of the important Bacterial diseases are: -

(a) Red stripe of sugarcane — Pseudomonas. rubrilineans.

(b) Fire blight of Apple & Pear—Erwinia amylovora.

(c ) Angular leaf spot of cotton Xanthmonas. malvaceum

(d) Citrus canker — Xanthomonas citri.

(e) Tondu of wheat — Cornybacterium tritici.

12. The biological control of malarial mosquito —B. sphaericus

13. Rickettsias — causes Rocky Mountain spotted fever.

14. The phenomenon of Conjugation was first observed — by Lederberg & Tatum 1946 in K-12 strain of Escherchia coli.

15. Transformation was first observed by — Griffith (1928.) in Pneumococcus pneumoniae.

16. Transduction was observed by Zinder and Lederberg (1952) in Salmonella typhimurium — is a phage mediated genetic transfer.

17. Klebsiella occurs symbiotically in Leaf nodule of Pavetta

18. In bacteria the condition where a single flageilum is present at one pole is — Monotrichous.

 

• Some bacteria are able to change their shape and size with changes in the environmental conditions. Such bacteria are called pleomorphic . e.g., Acetobactor.& Rhizobium(XYZ).
• Lophotrichous: There is a cluster of flagella at one end of the bacterial cell.
• Peritrichous: The bacterial cell has a large number of flagella which are distributed all over the cell surface.
• the break down of protein is called putrefaction. e.g., Bacillus subtilis.
• The anaerobic bacteria can live and multiply in the absence of free oxygen e.g., Clostridium botulinum.
• Bacillus, Clostridium are best examples of bacteria forming endospores. a thick wall around it called exosporium+spore coat+cortex-DAPA+core wall
• Ammonifying bacteria: These saprophytes break down the nitrogenous remains in dead plant and animal bodies and convert them into ammonia. This is called ammonification. e.g., Bacillus ramosus
• Nitrifying bacteria: Chemosynthetic autotrophs like Nitrosomonas and
• Nitrobacter, covert the ammonium compounds in the soil into nitrate salts. This process of converting ammonium salts in to nitrates is called nitrification.
• Denitrifying bacteria like Thiobacillus denitrificans convert nitratesand ammonia into free nitrogen. This process is called denitrification and reduces soil fertility.
• Vitamin B2 is manufactured by fermentative action of Clostridium acetobutylicum. & B12- Bacillus megatherium
• Gram positive bacteria retain purple colour with gram stain.
• Volutin granule- made up of RNA. Store RNA as source of N & P.
• Photosynthetic bacteria: Bacteria like purple sulphur bacteria contain pigments called bacteriochlorophyll. With the help of these pigments they trap solar energy and manufacture carbohydrates. Atmospheric carbon di oxide is used as carbon source. 2 type- Photolithotrophs- In bacterial photosynthesis inorganic compounds like Hydrogen sulphide is used as hydrogen donor. Photoorganotrophs-org. compound is used as hydrogen donor.eg. Purpile
• Chemosynthetic bacteria: They are non-photosynthetic autotrophs. They oxidize inorganic substances like nitrates, ammonia, etc. which are absorbed from the environment to obtain energy. This energy is used by the bacterial cell to combine carbon di oxide and water to form carbohydrates. This process of manufacturing food is called chemosynthesis.eg. Iron bacteria.
• Tobacco Industry: The leaves of tea, tobacco, and coffee fruits are fermented by the activity of certain bacteria to develop a characteristic flavour.e.g., Bacillus megatherium.