Kingdom Fungi

Subject: Science and Technology

Overview

Fungi are eukaryotic organisms with chitin cell walls that obtain nutrition by absorbing organic matter rather than photosynthesising. Learn the characteristics of Kingdom Fungi, the three types of fungal nutrition (saprotrophic, parasitic, and symbiotic), and study examples including mushroom, yeast, Penicillium, and Rhizopus.

1. Introduction to Kingdom Fungi

Kingdom Fungi includes a diverse group of eukaryotic organisms that are neither plants nor animals. Fungi were once classified with plants because they are mostly non-motile and have a cell wall. However, they differ fundamentally from plants in that they cannot photosynthesise. Instead they obtain nutrients by absorbing organic matter from their surroundings through secreted enzymes.

Key Definition: Fungi are eukaryotic, mostly multicellular organisms with a chitin cell wall. They are absorptive heterotrophs. They secrete digestive enzymes outside their body and absorb the digested nutrients back in.

Mushrooms growing on a mossy forest floor

Mushrooms growing on a mossy surface. They are saprotrophic fungi that obtain nutrition by breaking down dead organic matter in their surroundings.

2. Characteristics of Kingdom Fungi

Characteristic Description
Cell type Eukaryotic — membrane-bound nucleus present
Organisation Mostly multicellular; yeast is unicellular
Cell wall Present — made of chitin (not cellulose like plants)
Body structure Thread-like hyphae; a mass of hyphae is called mycelium
Chlorophyll Absent — cannot photosynthesise
Mode of nutrition Absorptive heterotrophic — saprotrophic, parasitic, or symbiotic
Reproduction By spores (sexual and asexual); yeast reproduces by budding

3. Modes of Nutrition in Fungi

Fungi cannot make their own food. They secrete digestive enzymes onto their food source and absorb the digested nutrients. Their nutrition falls into three types:

Saprotrophic Nutrition

Saprotrophic fungi feed on dead and decaying organic matter. They act as nature's decomposers, breaking down complex organic compounds and returning nutrients to the soil.

Examples: Mushroom (Agaricus), Bread mould (Rhizopus), Aspergillus

Parasitic Nutrition

Parasitic fungi obtain nutrients from a living host, causing disease or harm to the host organism.

Examples: Tinea (causes ringworm in humans), Puccinia (wheat rust, damages crops)

Symbiotic Nutrition

Symbiotic fungi live in a mutually beneficial relationship with another organism. Both partners benefit from the association.

Examples: Mycorrhizae (fungi + plant roots, improving water and nutrient absorption), Lichens (fungi + algae)

4. Common Examples of Fungi

Mushrooms growing in nature

Mushroom

Agaricus bisporus — edible saprotrophic fungus

 Bread mould growing on surface

Bread Mould

Rhizopus stolonifer — common household decomposer

 Yeast being used in bread baking dough

Yeast

Saccharomyces cerevisiae — used in baking and fermentation

 Blue green mould on citrus fruit representing Penicillium

Penicillium

Penicillium notatum — source of penicillin antibiotic

5. Comparison: Monera, Protista and Fungi

Feature Monera Protista Fungi
Cell type Prokaryotic Eukaryotic Eukaryotic
Organisation Unicellular Unicellular Mostly multicellular
Cell wall Peptidoglycan Variable / absent Chitin
Nutrition Auto / Heterotrophic Auto / Heterotrophic / Both Absorptive heterotrophic
Chlorophyll Some have (Cyanobacteria) Some have (algae, Euglena) Absent
Examples Bacteria, Cyanobacteria Amoeba, Euglena Mushroom, Yeast, Penicillium

6. Watch and Learn

The following videos explain Kingdom Fungi and its role in nature. Click on a thumbnail to watch.

Kingdom Fungi characteristics - YouTube

Kingdom Fungi — Characteristics and Examples

Clear overview of fungal characteristics, structure, and nutrition types.

 Types of fungi in nature - YouTube

Types of Fungi and Their Roles in Nature

Saprotrophic, parasitic, and symbiotic fungi explored with examples.
Things to remember

Things to Remember

  • Fungi are eukaryotic — they have a membrane-bound nucleus.
  • The cell wall of fungi is made of chitin — not cellulose like plants.
  • Fungi are heterotrophic by absorption — they cannot photosynthesise.
  • Most fungi are multicellular; yeast (Saccharomyces cerevisiae) is unicellular.
  • Body is made of thread-like hyphae; a collection of hyphae is called mycelium.
  • Three nutrition types: saprotrophic (dead matter), parasitic (living host), symbiotic (mutual benefit).
  • Penicillin antibiotic is obtained from Penicillium notatum.
  • Yeast is used in baking bread and brewing through fermentation.
  • Fungi reproduce primarily by producing spores.

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