CHARACTERISTICS AND CLASSIFICATION OF FUNGI

 

CHARACTERISTICS AND CLASSIFICATION OF FUNGI

CHARACTERISTICS AND CLASSIFICATION OF FUNGI.

The word fungus comes from the Latin word for mushrooms. Indeed, the familiar mushroom is a reproductive structure used by many types of fungi. However, there are also many fungi species that don’t produce mushrooms at all. Being eukaryotes, a typical fungal cell contains a true nucleus and many membrane-bound organelles. The kingdom Fungi includes an enormous variety of living organisms collectively referred to as Ascomycota, or true Fungi.

 

 

While scientists have identified about 100,000 species of fungi, this is only a fraction of the 1.5 million species of fungus probably present on earth. Edible mushrooms, yeasts, black mold, and the producer of the antibiotic penicillin, Penicillium notatum, are all members of the kingdom Fungi, which belongs to the domain Eukarya. Like bacteria, fungi play an essential role in ecosystems because they are decomposers- and participate in the cycling of nutrients by breaking down organic and inorganic materials to simple molecules.

 

Fungi often interact with other organisms, forming beneficial or mutualistic associations. For example most terrestrial plants form symbiotic relationships with fungi. The roots of the plant connect with the underground parts of the fungus forming mycorrhizae. Through mycorrhizae, the fungus and plant exchange nutrients and water, greatly aiding the survival of both species. Alternatively, lichens are an association between a fungus and its photosynthetic partner -(usually an alga).

 

Fungi also cause serious infections in plants and animals. In humans, fungal infections are generally considered challenging to treat. Unlike bacteria fungi do not respond to traditional antibiotic therapy because they are eukaryotes. Fungal Infections may prove deadly for individuals with compromised immune systems.

 

Fungi have many commercial applications. The food industry uses yeasts in baking, brewing and wine making. Many industrial compounds are byproducts of fungal fermentation. Fungi are the source of many commercial enzymes and antibiotics.

 

 

CHARACTERISTICS OF FUNGI

1. Fungi are eukaryotic organisms means they have true nucleus which are enclosed in membranes.

 

2. They are non-vascular organisms. They do not have vascular system. Xylem and Phloem are absent.

 

3. Fungi have cell walls.

 

4. There is no embryonic stage for fungi.

 

5. They reproduce by means of spores. There are sexual and asexual spores. Sexual spores are Oospores, Zygospores, Ascospores, Basidiospores, etc. and Asexual spores are Sporangiospores, Aplanospores, Zoospores, Conidia, etc.

 

6. They are typically non-motile.

 

7. Fungi lack the chlorophyll pigments present in the chloroplasts in plant cells and which are necessary for photosynthesis.

 

8. The vegetative body of the fungi may be unicellular or composed of microscopic threads called hyphae. 9. Yeasts are unicellular fungi that do not produce hyphae.

 

10. The structure of the fungi cell wall are composed of chitin.

 

11. Fungi are heterotrophic organisms. They don’t produce their own food, rather they obtain their food and energy from organic, substances, plants and animal matters.

 

12. Fungi grow best in acidic environment (tolerate acidic pH).

 

13. Fungi digest the food first and then ingest the food. To accomplish this, the fungi produce exoenzymes like Hydrolases, Lyases, Transferase, etc.

 

14. Fungi store their food as starch.

 

 

15. Many of the fungi have a small nucleus with DNA.

 

16. During mitosis the nuclear envelope is not dissolved.

 

7 Nutrition in fungi – they are saprophytes (gets energy from dead and decaying matters), or parasites (lives in a host, attack and kill) or symbionts (mutually beneficial).

 

18. Optimum temperature of growth for most saprophytic fungi is 20-30°C while (30-37)°C for parasitic fungi

 

19. Growth rate of fungi is slower than that of bacteria.

 

20. Reproduction in fungi is both by sexual and asexual means

 

21. Sexual state is referred to as teleomorph (fruiting body), asexual state is referred to as anamorph(mold like).

 

22. Pheromone is a chemical substance produced by fungi, which leads to the sexual reproduction between male and female fungi cells.

 

23. Some fungi are macroscopic and can be seen by naked eyes. Mold or mushrooms are examples of macroscopic form of fungi.

 

24. In 1991, a landmark paper estimated that there are about 1.5 million fungi on the earth.

 

25. Only about 300 species of fungi are infectious to human. Examples: Candida albicans, Aspergillus, Blastomyces, Coccidioides.