Fungi and Symbiotic Relationships

Questions and Answers

What type of fungus is most commonly associated with lichen symbiosis?

Basidiomycete

Zygomycete

Oomycete

Ascomycete (correct)

What is the main function of fungi in the guts of grazing mammals?

Breakdown of plant material (correct)

Synthesis of nitrogen

Formation of mycorrhizae

Production of antibiotics

What is the role of cyanobacteria in lichen symbiosis?

Provision of organic nitrogen (correct)

Formation of soredia

Provision of carbon compounds

Degradation of fungal hyphae

What is the term for the symbiotic relationship between fungi and plant roots?

Mycorrhizae Signup and view all the answers

What is the primary function of mycorrhizae in natural ecosystems?

Facilitation of plant nutrient uptake Signup and view all the answers

Which type of fungus is involved in the decomposition of organic matter?

All of the above Signup and view all the answers

What is the term for the small clusters of hyphae with embedded algae formed during asexual reproduction in lichens?

Soredia Signup and view all the answers

What is the significance of lichens in the colonization of land by plants?

They may have helped to pioneer the colonization of land by plants Signup and view all the answers

What is the primary function of mycorrhizal fungi in a mutualistic relationship with plants?

To deliver phosphate ions and minerals to plants Signup and view all the answers

Which type of mycorrhizal fungi penetrates root cells?

Arbuscular mycorrhizal fungi Signup and view all the answers

What is the characteristic feature of coenocytic fungi?

Lack of septa and a continuous cytoplasmic mass Signup and view all the answers

What is the primary function of mycelium in fungi?

To absorb nutrients from the environment Signup and view all the answers

Which of the following statements about mycorrhizae is false?

They are in a commensalistic relationship with plants Signup and view all the answers

What is the estimated number of fungal species?

1.5 million Signup and view all the answers

What is the unique feature of fungi that helps identify them?

Presence of chitinous cell walls Signup and view all the answers

What is the role of enzymes in fungal nutrition?

To break down complex molecules into smaller organic compounds Signup and view all the answers

What is the ecological importance of decomposition performed by fungi?

It recycles vital nutrients and breaks down organic matter Signup and view all the answers

Which of the following is an example of mutualism in fungi?

Lichens Signup and view all the answers

What is the primary role of Basidiomycetes in ecosystem?

Decomposition of organic matter Signup and view all the answers

Which of the following processes is NOT facilitated by mycorrhizal fungi?

Capture of prey by fungi Signup and view all the answers

What is the characteristic of fungal cell walls?

Contain chitin Signup and view all the answers

Which type of fungi has specialized hyphae called haustoria?

Fungi that capture prey Signup and view all the answers

Which of the following is a characteristic of Ascomycetes?

They have a sac-like structure for spore production Signup and view all the answers

What is the structure of fungi composed of?

A mycelium that is an interwoven mass of hyphae Signup and view all the answers

Study Notes

Fungus-Plant Mutualism

Mycorrhizae are essential in natural ecosystems and agriculture
Plants harbor harmless symbiotic endophytes, fungi that live inside leaves or other plant parts
Endophytes produce toxins that deter herbivores and defend against pathogens
Most endophytes are ascomycetes

Fungus-Animal Mutualism

Fungi share their digestive services with animals
Fungi help break down plant material in the guts of cows and other grazing mammals
Many species of ants use the digestive power of fungi by raising them in “farms”

Lichens

A lichen is a symbiotic association between a photosynthetic microorganism and a fungus
Millions of photosynthetic cells are held in a mass of fungal hyphae
The photosynthetic component is green algae or cyanobacteria
The fungal component is most often an ascomycete
The algae provide carbon compounds, cyanobacteria provide organic nitrogen, and fungi provide the environment for growth
Lichens are important pioneers on new rock and soil surfaces
Lichens may have helped the colonization of land by plants 550-600 million years ago
Lichens are sensitive to pollution, and their death can be a warning that air quality is deteriorating

Fungal Structure

The body of a fungus is made of a mycelium, which is an interwoven mass of hyphae
Most fungi have hyphae divided into cells by septa, with pores allowing cell-to-cell movement of organelles
Coenocytic fungi lack septa and have a continuous cytoplasmic mass with hundreds or thousands of nuclei

Mycorrhizae

Mycorrhizae are mutually beneficial relationships between fungi and plant roots
Mycorrhizal fungi deliver phosphate ions and minerals to plants
Types of mycorrhizal fungi:
- Ectomycorrhizal fungi (do not penetrate root cells)
- Arbuscular mycorrhizal fungi (penetrate root cells)

Fungal Characteristics

Fungi are diverse and widespread
They are essential for the well-being of most terrestrial ecosystems
About 100,000 species of fungi have been described
It is estimated there are actually 1.5 million species of fungi

Fungal Nutrition

Fungi are heterotrophs and absorb nutrients from outside of their body
Fungi use enzymes to break down a large variety of complex molecules into smaller organic compounds
The versatility of these enzymes contributes to fungi’s ecological success
Fungi exhibit diverse lifestyles:
- Decomposers
- Parasites
- Mutualists

Fungal Morphology

Some species grow as either filaments or yeasts; others grow as both
The morphology of multicellular fungi enhances their ability to absorb nutrients
Fungi consist of mycelia, networks of branched hyphae adapted for absorption
A mycelium’s structure maximizes its surface area-to-volume ratio
Fungal cell walls contain chitin

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Description

This quiz explores the relationships between fungi and other organisms, including protists, cyanobacteria, and plants. It covers different types of fungi and their interactions with other organisms.