Fungi Characteristics and Functions Quiz

Fungi Overview

• Fungi are eukaryotic, heterotrophic, and absorptive organisms
• They range in size from single-celled yeasts to multicellular mushrooms
• Once considered plants, fungi have little in common with them, but are more closely related to animals
• Fungi play vital roles in ecosystems as decomposers
• Symbiotic relationships with plants are essential to nutrient cycling in ecosystems
• Fungi provide humans with food (mushrooms, truffles), beverages (beer, wine), and drugs (cyclosporine)
• Fungi can also cause diseases in plants and animals, and damage property

Benefits of Fungi

• Ecosystems: Decompose organic matter, forming symbiotic relationships with plants, and recycling nutrients
• Humans: Provide food (mushrooms, truffles, etc.), drinks (beer, wine), and medications (cyclosporine)

Harm Caused by Fungi

• Cause diseases in plants and animals
• Damage harvests
• Rot wood and buildings

Similarities Between Fungi and Plants

• Sessile (stationary)
• Multicellular
• Grow from the ground
• Possess a stem-like structure

Differences Between Fungi and Plants

• Fungi are not photosynthetic
• Fungi are heterotrophic (cannot produce their own food)
• Fungi lack true roots
• Fungi have cell walls composed of chitin (plants have cellulose cell walls)

Fungal Structure

• The visible parts of a fungus are primarily reproductive structures.
• The body of fungi is called a mycelium, composed of a vast network of microscopic threadlike filaments known as hyphae.

Fungal Reproduction

• Most parts of a fungus have haploid chromosomes; in contrast, humans possess mostly diploid chromosomes
• Spores are dispersed by wind or water, restarting the fungal life cycle
• A large mushroom may release 100 million spores in a single hour

Fungal Nutrition

• Fungi secrete digestive enzymes onto organic matter and absorb the resulting nutrients as food
• This feeding method demands a large surface area to fully interact with the ingested material.
• Fungi act as decomposers, absorbing nutrients from dead organisms and returning them to the ecosystem.

Symbiotic Relationships of Fungi

• Parasitic: Absorb nutrients from living host cells (Example: athletes' foot)
• Predatory: Some soil fungi trap tiny nematode worms
• Mutualistic:
• Mycorrhizae: Fungi form symbiotic relationships with plant roots, assisting plants in absorbing soil nutrients in exchange for sugars.
• Lichens: Fungi and either cyanobacteria or green algae form symbiotic relationships, where the algae provides the fungi with sugars, and the fungus provides a protective, moisture-retentive environment for the algae.

Conditions for Fungal Growth

• Continuous moisture
• Continuous food supply
• Ideal temperature

Major Fungal Phyla

• Chytridiomycota
• Zygomycota
• Glomeromycota
• Ascomycota
• Basidiomycota

Ascomycota

• Characterized by sac-like structures called asci where spores develop
• Yeast and some types of morels are examples

Basidiomycota

• Includes mushrooms and puffballs
• Release basidiospores from club-shaped basidia in the fruiting body forming a symbiotic relationship with plants
• Decomposers

Chytridiomycota

• Mostly unicellular and aquatic fungi
• Possess spores with flagella
• Important decomposers of cellulose and keratin (e.g., wood and hair)

Glomeromycota

• All species form symbiotic relationships with plant roots, known as mycorrhizae forming relationships

Zygomycota

• Includes bread and fruit molds
• Mostly soil fungi
• Some are parasitic insects

Homework Assignment

• Complete the Fungi Worksheet