DEFINITIONS AND KEY POINTS FOR OBJECTIVES OF MONERA BECTERIA

 

TERMS                                                                      II

DEFINITIONS                                             I

Gram positive bacteria They are stained purple with this staining

  1. They  forms  CV-   Icomplex

(Crystalviolet complex   I) and  retainthe
primary dye colour.

They  arestained        pink  with     this         staining

technique. They retain secondary dye colour.

Gram              Negative

bacteria

Slime Some bacteria are covered with loose, soluble shield of macromolecules called slime.
Pili Pili are hollow, non-helical and filamentous appendages present on cell wall.
Cytoplasmic matrix The cytoplasmic matrix is a substance present

between   the   plasma    membrane  and   the
nucleoid.

Nucleoid The nuclear material or DNA of bacteria aggregates to form irregular shaped dense body called nucleoid.
Plasmids Plasmids are circular, double stranded extra chromosomal DNA molecules in bacteria.
Spores The metabolically dormant (inactive) bodies with thick wall are called spores.
Conjugation The genetic recombination in which bacteria

exchange     genetic    material    through
cytoplasmic bridge is called conjugation.

 

MODEL SUBJECTIVE QUESTION

  1. Describe the cell wall of bacteria?
  2. Describe Gram staining technique.
  3. Write note on locomotion in bacteria.
  4. Describe internal organization of bacteria.
  5. Describe asexual reproduction in bacteria.
  6. Describe different methods of sexual reproduction in bacteria.
  7. Give classification of bacteria.
  8. Give general characters of cyanobacteria.
  9. Describe economic im rtance of rokaryotes.

SHORT QUESTIONS

  1. Give compositimi of cell wall of bacteria.

Ans: The cell walls of most bacteria have a unique macromolecule called peptidoglycan. Its amount is different in different types of bacteria. It is composed of long framework of glycan (glucose) chains. These glycan chains are linked with peptide fragments. The intact cell wall also contains some molecules of sugar, techoic acid, lipoproteins and Lipopolysaccharides. These molecules are linked to peptidoglycan.

  1. What are Gram positive bacteria? Give composition of

their cell wall.     •

Ans: They are stained purple with this staining technique. They forms CV- I complex (Crystal violet complex I) and retain the primary dye colour. Gram positive bacteria have simple cell wall. It has large amount of peptidoglycan. It has lesser amount of lipopolysaccharides.

  1. What are Gram Negative bacteria? Give composition of their cell wall.

Ans: They are stained pink with this staining technique. They retain secondary dye colour. Gram negative bacteria have lesser amount of peptidoglycan. It has more complex structure. An outer membrane of lipopolysaccharides is present outer to the peptidoglycan layer. Grain negative species are more dangerous than the Gram positive bacteria. The lipopolysaccharides layer is often toxic. This layer protects the bacteria from the immune system of host. Gram negative bacteria are more resistant to antibiotics.

  1. What are capsules? Give their function.

Ans: Some bacteria produce capsule out side the cell wall. It is made up of repeating units of polysaccharides or proteins or both. The capsule is tightly bound with the cell wall. It has thick and gummy nature. It makes the encapsulated bacteria sticky.

  1. What are pill? Give their functions.

Ans: Pili are hollow, non-helical and filamentous appendages present on cell wall. Pili are smaller than the flagella. True phi are present only in gram-positive bacteria. They are made up of special proteins called pilin. Pili are not involved in locomotion. They are primarily involved conjugation. Conjugation is a mating process. Some pili are used for the attachment of bacteria with various surfaces.

  1. What are the functions of flagella?

Ans: The primary function of flagella is locomotion. Bacteria can detect a chemical signals with the help of flagella and move in its response. Such type of behaviour is called Chemotaxis.

  1. What are mesosomes? Give their functions.

Ans: The cell membrane invaginates to form mesosomes. Mesosomes are in the form of vesicles, tubules or lamellae. Mesosomes are involved in DNA replication and cell division. Some mesosomes are also involved in the export of exocellular enzymes. Respiratory enzymes are also present on the mesosomes.

  1. What are plasmids? Give their functions.

Ans: Plasmids are circular, double stranded extra chromosomal DNA molecules in bacteria. Many bacteria contain plasmids in addition to chromosomes. They are self – replicating bodies. Plasmids are not essential for the bacterial growth and metabolism. Plasmids contain drug and heavy metals resistant genes. Disease and insect resistant genes are also present on them. Plasmids play an important role in conjugation.


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  1. Differentiate between cyst and spore.

Ans: The metabolically dormant (inactive) bodies with thick wall

are called spores. Cysts are dormant, thick- walled and desiccating resistant structure.

  1. What is endospore? Give its function.

Ans: Bacteria also develop single endospore. Endospores are used to pass unfavourable conditions. The endospore germinates in favourable condition and develops new single bacterium. So endospore formation is not a mean of reproduction.

  1. What are Phototropic anaerobic bacteria?

Ans: They are photoautotroph.                       They have different
photosynthetic equipment than plants. They use I-12S as electron source. They are anaerobes. They are found in pond, lake, and ocean sediments. They have different groups like bacteria and the green sulfur bacteria. Example: Chrommium

  1. What is chromoplasm?

Ans: The outer region is blue green pigmented. It is called chromoplasm. Chromoplasm contain pigments chlorophyll, carotine, myxothanhophyll and phycocyanin. It also contains oil droplets and glycogen. Certain gas vesicles are also present in it.

  1. What are Hormogonia?

Ans: The broken pieces of a filament are called horrnogonia. Double concave discs of gelatinous material are formed between two cells. It is called separation disc. The filaments break at these points and form hormogonia.

  1. What are Hormospores?

Ans: Under unfavourable conditions, some hormogonia develop thick wall. They are called horrnospores. They germinate directly into new filament in favourable conditions.

OBJECTIVESII

Multiple Choice Questions (MCQs)

  1. Hollow, non-helical and filamentous appendages present on cell wall are:

(a) Capsule      (b) Pili              (c) mesosome (d) Plasmids

  1. Some bacteria are covered with loose, soluble shield of macromolecules called:

(a) Capsule      (b) Pili              (c) Slime          (d) Plasmids

  1. The structure made up of , repeating units ofpolysaccharides or proteins or both is:

    (a) Capsule      (b) Pili            (c) Slime          (d) Plasmids

    1. The nuclear material or DNA of bacteria aggregates to form irregular shaped dense body:

    (a) Nucloid      (b) Pili            (c) Slime          (d) Plasmids

    1. The circular, double stranded extra chromosomal DNA molecules in bacteria are

    (a) Nucloid      (b) Pili            (c) Slime          (d) Plasmids

    1. Plasmids play an important role in:

    (a) Conjugation (b) Division   (c) Regulation (d) Protection

    1. The metabolically dormant (inactive) bodies with thick wall are called:

    (a) Spore          (b) Pili            (c) Slime          (d) Cyst

    1. The dormant, thick- walled and desiccating resistant structure is:

    (a) Spore          (b) Pili            (c) Slime          (d) Cyst

    1. The genetic recombination in which bacteria exchange
      genetic material through cytoplasmic bridge is:

    (a) Transformation     (b) Transduction          (d) Conjugation

    1. The genetic recombination in which bacteria absorbs
      naked DNA is:

    (a) Transformation     (b) Transduction          (d) Conjugation

    1. Chemoautotrophic bacteria is:

    (a) Nostoc        (b) Nitrobactor (c) Clostridium (d)Azutobacter

    1. Nitrogen fixing bacteria are:

    (a) Nostoc        (b) Nitrobactor (c) Clostridium (d)Azotobacter

    1. Phototropic anaerobic bacteria are:

    (a) Chromatium(b)Nitrobactor (c) Clostridium (d)Azotobacter

    1. Pycoblins are present in:

    (a) Nostoc        (b) Nitrobactor (c) Clostridium (d) Azotobacter

    1. The Ammonifying bacteria are:

    (a) Nitrobactor (b)Azobactor (c) Pseudomonas          (d) Nostoc

    1. The denitrifying bacteria are:

    (a)Nitrobactor (b)Azobactor (c) Pseudomonas           (d) Nostoc
    Answers

    1. (b) 2. (c) 3. (a) 4. (a) 5. (d) 6. (a) 7. (a) 8. (d) 9. (d) 10. (a) 11. (a) 12. (d) 13. (a) 14. (a) 15. (a) 16. (c)

 

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