Question

How many types of prokaryotes are there?

Answer 1

Prokaryotes:

1. These are those organisms that have primitive cells.
2. Their nucleus does not have any nuclear envelope.
3. No membrane-bound organelles are present in them.
4. Prokaryotes are unicellular organisms.
5. They have naked circular DNA.
6. Types of prokaryotic cells: -
   1. Bacteria -
      1. Also referred to as eubacteria which means true bacteria.
      2. It includes cyanobacteria mainly.
      3. Cyanobacteria are photosynthetic bacteria.
      4. These are unicellular, filamentous, colonial, freshwater, or marine bacteria.
      5. Asexual reproduction in them occurs by fragmentation, fission, or spore formation.
      6. Example - Trichodesmium erythraeum, Chromatium, etc.
   2. Archaea -
      1. It includes Archaebacteria.
      2. These are also called ancient bacteria or oldest living fossils.
      3. These bacteria are mainly found living in very adverse and hostile situations.
      4. Their cell wall lack peptidoglycan and is made up of non-cellulosic polysaccharide and protein thus, they possess a different structure of cell wall.
      5. Their cell membrane has reduced fluidity due to the presence of branched-chain lipids in them.
      6. Example - Methanococcus, Halococcus, Thermoproteus, etc.