Question

What are pleomorphic bacteria?

Answer 1

Hint: Pleomorphism refers to having different shapes. Some species of bacteria have varied shapes because of the absence of cell walls.

Complete Answer:
We can solve this question by understanding that a cell wall is an essential structure required to provide a shape to the cell.
- In these pleomorphic forms the cell wall is absent and an immediate plasma membrane forms the outermost boundary of the cell. As there is no cell wall, these organisms are able to change their shape and are thus called as pleomorphic.
- Pleomorphism is defined as the existence of irregular and different forms present within a species or strain of microorganisms, this is a condition which is similar to polymorphism in higher organisms.
- Thus, Mycoplasma is a genus of bacteria which can be present in different forms and shapes thus are called pleomorphic bacteria.
- The different shapes are - like club-shaped, curved, coccoid and filamentous. The most common example that can be considered is the Corynebacterium spp.
- Corynebacterium are Gram-positive and aerobic bacteria. They are found in various shapes like - bacilli (rod-shaped), club-shaped, which gave the genus its name (coryneform means "club-shaped").

Additional information:
- Mycoplasmas have plasma membranes rich in sterols and lipoglycan. There is absence of a rigid cell wall which allows them to change their shape according to the environment, i.e., pleomorphic.
- Pleomorphism is also found in species of Helicobacter pylori, and are found to exist in different forms like helix-shaped form (curved rod) as well as and a coccoid form.

Note: Mycoplasma is a genus of Monera which are prokaryotic organisms. These organisms lack a cell wall. The cell membrane is composed of three layers of sterols or lipoproteins which protects the cell.