Bacteria

Organisms which are extremely small in size and can only be seen under a microscope but not by naked eyes are called microorganisms or microbes.

Microorganisms are found in a variety of shapes and sizes. They are divided into five groups namely bacteria, fungi, protozoa, virus and algae.

Bacteria were first observed by Leeuwenhoek under a microscope. Bacteria belong to the kingdom Monera.  The branch of science that deals with the study of bacteria is called bacteriology. Bacteria vary in size and shapes. The smallest bacterium belongs to genus mycoplasma.

Depending upon the shapes; bacteria may be coccus, bacillus, spirillum or vibroid.

The cell wall of bacteria composed of protein like material (Pepidoglycan). It provides definite shape and protection to bacterial cell.
DNA is the genetic material present in bacteria.

In some bacteria, extra-chromosomal DNA called plasmid may be present. Flagella are the locomotory organs in bacteria.
Pilli help in sexual reproduction by attaching donor cell to recipient cell.

On the bases of respiration, bacteria may be aerobic or anaerobic.

Depending upon the mode of nutrition, bacteria may be autotrophic (chemosynthetic and photosynthetic) or heterotrophic (saprophytes, parasites and symbionts).

Bacteria reproduce both asexually and sexually by the process of binary fission and conjugation respectively.

Bacteria undergo spore formation as an adaptation to survive under unfavourable conditions.

 

To Access the full content, Please Purchase

  • Q1

    What is the asexual mode of reproduction in bacteria?

    Marks:1
    Answer:

    The asexual reproduction in bacteria occurs by the process of binary fission.

    View Answer
  • Q2

    Name the nitrogen fixing bacteria present in the root nodule of leguminous plants.

    Marks:1
    Answer:

    Rhizobium is present in the root nodule of leguminous plants.

    View Answer
  • Q3

    Who introduced the term “bacterium”?

    Marks:1
    Answer:

    The term bacterium was introduced by Christian Gottfries Ehrenberg in 1828.

    View Answer
  • Q4

    Name the kingdom to which bacteria belong.

    Marks:1
    Answer:

    Bacteria belong to the kingdom Monera.

    View Answer
  • Q5

    What is bacteriology?

    Marks:1
    Answer:

    The branch of science that deals with the study of bacteria is called bacteriology.

    View Answer