Question

Define microbes.

Answer 1

Hint:- As the term itself suggests, microbes or microorganisms are very small creatures and they cannot be seen by the naked eyes. Microscopes are needed to visualize microbes. They can be both harmful as well as beneficial for life. Let us know more about microbes so that we can have a clear understanding of microbes.

Complete Answer:-
Let us first know the general characteristics of microbes.
1. So, microbes or microorganisms are way too small to be seen by the naked eyes and we need microscopes to visualise them. They may exist as unicellular organisms or in the form of clusters or colonies of cells.
2. Distribution of microorganisms is very diverse and includes all unicellular organisms. They show a very high range of habitat diversity and can be found in regions from the poles to equator. Some of them are also adapted to inhabit the extreme of conditions such as very hot or very cold regions, etc. They form the normal microbiota of multicellular organisms which is very important for the proper functioning of the immune system.
Let us now know about the major types of microbes. They are-
1. Bacteria- they are unicellular which generally reproduce by binary fission. They mostly require moist conditions for growth and can live in a wide range of temperatures. They tend to multiply very fast when given the optimum conditions. There are predominantly four bacterial shapes- spiral, rod, comma and spherical.
2. Fungi- fungi are eukaryotic microbes which reproduce both by sexual and asexual means. They can be broadly divided into two groups-
3. Molds- filaments called hypha containing fungi. Network of hyphae is called mycelium. Example- Penicillium, Aspergillus, etc.
4. Yeast- single-celled fungi reproducing mostly by budding. Ex- Saccharomyces cerevisiae.
5. Algae- chlorophyll containing microbes capable of carrying out photosynthesis. They are eukaryotic as they have membrane-bound nuclei. They can exist as single-celled, in colonies or in filamentous forms. They reproduce sexually as well as asexually.
6. Protozoa- they are eukaryotic and single-celled which lack a rigid cell wall and are usually devoid of chloroplasts. They can exhibit a variety of shapes, cell structure and forms. Ex- Amoeba, Paramecium.
7. Virus- they are acellular nucleoprotein materials. They cannot replicate outside the hot organism and are thus obligate parasites. They can either contain single or double stranded DNA or RNA as the genetic material but not both and can be enveloped or non-enveloped. Example of viral diseases- common cold, AIDS, measles,etc.

Note:-
1. Microbes are the causative agents for many diseases such as typhoid, common cold, AIDS, candidiasis, etc.
2. But they also have beneficial roles such as in the production of vaccines and antibiotics, cycling of nutrients, production of enzymes, etc.
3. Yeast is widely used in beverage industries for the production of ethanol by fermentation process.