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It is a short ppt on bacteria

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  1. 1. Bacteria Name-Sudipta Sarkar Class- XI Sec-Sc(B) Roll no.-27
  2. 2. Acknowledgement  I would like to express my special thanks of gratitude to  my Biology teacher Mrs Smita as well as our principal  madam Dr. Suchitra Bhattacharya who gave me the  golden opportunity to do this wonderful project for OTBA  on the topic  “Bacteria” which also helped me in doing a  lot of Research and I came to know about so many new  things I am really thankful to them. Secondly i would also like to thank my parents and  friends who helped me a lot in finalizing this project  within the limited time frame.
  3. 3. Contents SRL # Topic 1 Introduction (with a picture of Bacteria) 2 Comparision of the size of Bacteria with other organisms 3 Key concept of Bacteria 4 Structure of Bacteria 5 Identification of Bacteria on the basis of shape 6 Mode of reproduction of the Bacteria 7 Nutrition and growth 8 Speciality of Bacteria 9 Identification of Bacteria 10 Bacterial Cell wall 11 Hazards of Bcteria 12 Beneficts of bacteria 13 Conclusion 14 Bibliography
  4. 4. INTRODUCTION Bacteria are VERY small!
  5. 5. Euglena 100 µm Plant cell 35-80 µm Animal cell 5-30 µm Spirocheta 10 µm Bacteria are small compared to cells with nuclei Virus 20-200 nm
  6. 6. Bacteria compared to white blood cell that will eat it!
  7. 7. Key Concepts about Bacteria  Kingdom Monera  Prokaryote=no nucleus or internal compartments  All are single cells  Single circular piece of DNA
  8. 8. Structure of Bacteria Structure Function Cell Wall Protects and gives shape Outer Membrane Protects against antibodies Cell Membrane Regulates movement of materials, contains enzymes important to cellular respiration Cytoplasm Contains DNA, ribosomes, essential compounds Chromosome Carries genetic information. It is circular
  9. 9. Structure of Bacteria Plasmid Contains some genes obtained through recombination Capsule & Slime Layer Protects the cell and assist in attaching cell to other surfaces Endospo re Protects cell against harsh environments Pilus Assists the cell in attaching to other surfaces Flagellu m Moves the cell
  10. 10. Shapes- How bacteria are identified!  Bacilli- rod shaped  Spirilla- spiral shaped  Cocci- sphere shaped  Staphylococci- grape-like clusters  Streptococci- in chains
  11. 11. Bacillus bacteria are rod shaped
  12. 12. Spirillium bacteria have a corkscrew shape
  13. 13. Coccus bacteria are sphere or ball shaped
  14. 14. Staphylobacteria occur in clumps, such as this staphylococcus bacteria that cause common infections of cuts
  15. 15. Streptobacteria occur in chains, like this streptococcus bacteria
  16. 16. Bacterial Reproduction: Binary Fission
  17. 17. Conjugation  Genetic information transferred on plasmids - and sometimes antibiotic resistance
  18. 18. Nutrition and Growth  Autotroph- producer, makes energy from environmental sources  Chemoautotrophs- Take Hydrogen from NH3 or H2S and oxidize it using the energy to make amino acids and proteins  Photoautotrophs- photosynthetic- Uses sunlight for energy
  19. 19. Nutrition and Growth  Heterotroph- feed on organic material formed by other organisms  Decomposers  Secrete enzymes in their organic environment and then absorb the nutrients  They can metabolize their host
  20. 20. Endospores  Some bacteria can form endospores, which are non-replicative cell forms that are highly resistant to environmental factors. Endospore
  21. 21. Gram Stain- Another way to identify Bacteria Purple= Gram Positive Pink= Gram Negative
  22. 22. Bacterial Cell Walls •Peptidoglycan is the material that makes up bacterial cell walls Thicker peptidoglycan layer but not outer membrane means gram + Thinner peptidoglycan layer with an outer membrane means gram -
  23. 23. How do Bacteria cause disease?  Metabolize their host for food (Heterotrophic bacteria)  Secrete a toxin which can attack other body parts (Botulism is an example)  Contain an endotoxin in their cell wall which is released when the bacterium dies. An example of this is salmonella.
  24. 24. How can Bacteria work to our benefit?  Digest waste at sewage plants  Chemical industry- make acetone and butanol  Pharmaceutical- vitamins, antibiotics, insulin  Food- yogurt, cheese, alcoholic beverages  Decomposer  Nitrogen fixers  Symbiosis
  25. 25. Conclusion  Through this project I came to know a lot about Bacteria its characteristic features and also how to identify it. This project was a great help to me as this information might help me in my future.
  26. 26. Bibliography  https//  https//
  27. 27. THANK YOU