Fungal Diversity: Phyla Chytridiomycota and Zygomycota

Questions and Answers

What is the characteristic feature of Coenocytic fungi?

A continuous cytoplasmic mass with hundreds or thousands of nuclei (correct)

Hyphae with chitinous cell walls

Specialized hyphae to capture prey

Hyphae divided into cells by septa

Almost all vascular plants have mycorrhizae.

True

What do mycorrhizal fungi deliver to plants?

Phosphate ions and minerals

The body of fungi is made up of a _______________________, which is an interwoven mass of hyphae.

mycelium Signup and view all the answers

Which of the following is a unique feature of fungal cell walls?

Presence of chitinous cell walls Signup and view all the answers

Mycorrhizae are in a commensalistic relationship with plants.

False Signup and view all the answers

Match the type of mycorrhizal fungi with its characteristic.

Ectomycorrhizal fungi = Penetrate root cells Arbuscular mycorrhizal fungi = Do not penetrate root cells Signup and view all the answers

What is the term for specialized hyphae that allow fungi to penetrate the tissues of their host?

Haustoria Signup and view all the answers

What is the main function of enzymes in fungi?

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

Fungi are autotrophs, meaning they produce their own food.

False Signup and view all the answers

What is the estimated number of fungal species?

1.5 million Signup and view all the answers

Fungal cell walls contain the substance _______________________.

chitin Signup and view all the answers

Match the following types of fungi with their characteristics:

Decomposers = Break down organic material and recycle vital nutrients Parasites = Obtain nutrients by harming other organisms Mutualists = Form symbiotic relationships with other organisms Signup and view all the answers

What is the term for a network of branched hyphae adapted for absorption?

Mycelium Signup and view all the answers

Fungi only grow as filaments.

False Signup and view all the answers

Describe the structure of multicellular fungi that enhances their ability to absorb nutrients.

The morphology of multicellular fungi, which includes a network of branched hyphae, maximizes their surface area-to-volume ratio, allowing them to absorb nutrients more efficiently. Signup and view all the answers

What is unique about the spores of chytrids among fungi?

They are flagellated Signup and view all the answers

Zygomycetes are commonly called sac fungi.

False Signup and view all the answers

What is the function of zygosporangia in zygomycetes?

The site of karyogamy and then meiosis, resistant to freezing and drying, can survive unfavorable conditions Signup and view all the answers

Glomeromycetes form _______________ mycorrhizae.

arbuscular Signup and view all the answers

What is a characteristic of the hyphae of zygomycetes?

They are coenocytic Signup and view all the answers

Ascomycetes reproduce asexually by producing enormous numbers of conidia.

True Signup and view all the answers

Match the following fungal phyla with their characteristics:

Chytridiomycota = Flagellated spores Zygomycota = Coenocytic hyphae Glomeromycota = Arbuscular mycorrhizae Ascomycota = Sac-like asci Signup and view all the answers

What is the term for the symbiotic relationship formed by glomeromycetes with plant roots?

Arbuscular mycorrhizae Signup and view all the answers

What is the number of estimated species of fungi on Earth?

1.5 million Signup and view all the answers

Fungi are autotrophic, meaning they produce their own food.

False Signup and view all the answers

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

Mycorrhizae Signup and view all the answers

Fungi absorb nutrients through their _______________________ membrane.

plasma Signup and view all the answers

Match the type of fungi with its characteristic:

Septate fungi = Have partial divisions between their nuclei Coenocytic fungi = Lack dividers and have a single, large cell containing many nuclei Signup and view all the answers

The visible parts of fungi, such as mushrooms, are the main body of the fungus.

False Signup and view all the answers

What is unique about fungal cell walls?

They are made of chitin Signup and view all the answers

What is the term for the network of branched hyphae adapted for absorption?

Mycelium Signup and view all the answers

How do fungi attract a mate in the dark environment?

By producing pheromones Signup and view all the answers

Yeast cells are multicellular organisms.

False Signup and view all the answers

What is the only diploid stage in the fungal life cycle?

Zygote Signup and view all the answers

Fungi can engage in both sexual and _______________ reproduction.

asexual Signup and view all the answers

Match the following stages in the fungal life cycle with their descriptions:

Zygote = The only diploid stage in the fungal life cycle. Dikaryon = A structure formed after the nuclei of two fungi come close together but do not fuse immediately. Haploid spores = Produced through meiosis in the zygote stage. Signup and view all the answers

What is the advantage of asexual reproduction in fungi?

It allows fungi to take advantage of their environment and reproduce quickly when resources are abundant. Signup and view all the answers

All fungi are multicellular.

False Signup and view all the answers

What is the result of the fusion of the nuclei in the dikaryon stage?

Zygote Signup and view all the answers

What is the common name for the phylum Basidiomycota?

Club fungi Signup and view all the answers

Gills in Basidiomycota are used for respiration.

False Signup and view all the answers

What is the process through which basidiospores are created in the basidia?

meiosis Signup and view all the answers

The reproductive body in Basidiomycota is referred to as the _______________.

basidio Signup and view all the answers

Match the following terms with their definitions:

Basidia = Club-like structure where spores are found Basidiospor = Spores created in the basidia Basidio = Reproductive body Carp = Entire structure growing above ground Signup and view all the answers

How many basidiospores are created in each basidia?

Four Signup and view all the answers

What is the name of the structure that holds spores in Ascomycota?

Ascus Signup and view all the answers

Ascomycota reproduce asexually by producing conidia.

False Signup and view all the answers

What are the structures formed in each ascus in Ascomycota during meiosis?

Eight ascospores Signup and view all the answers

The process that occurs in the ascus to form ascospores is called _______________________.

meiosis Signup and view all the answers

Match the following terms with their definitions:

Ascocarp = The reproductive structure in Ascomycota Ascus = The spore-making structure within the ascocarp Meiosis = The process that occurs in the ascus to form ascospores Ascospores = The spores formed in the ascus, specifically from Ascomycota Signup and view all the answers

What is the result of the fusion of hyphae in Ascomycota?

An ascocarp Signup and view all the answers

Study Notes

Fungal Diversity

Phylum Chytridiomycota:
- Found in freshwater and terrestrial habitats
- Can be decomposers, parasites, or mutualists
- Early divergent group in fungal evolution
- Unique feature: flagellated spores (zoospores)
Phylum Zygomycota:
- Diverse life histories (fast-growing molds, parasites, commensal symbionts)
- Life cycle of black bread mold (Rhizopus stolonifer) is typical of the phylum
- Coenocytic hyphae with haploid spores produced in asexual sporangia
- Sexual reproduction involves zygosporangia, which are resistant to freezing and drying
Phylum Glomeromycota:
- Previously classified as Zygomycota, now in a separate clade
- Form arbuscular mycorrhizae
Phylum Ascomycota:
- Found in marine, freshwater, and terrestrial habitats
- Produce sexual spores in saclike asci contained in fruiting bodies (ascocarps)
- Commonly called sac fungi
- Vary in size and complexity (unicellular yeasts to elaborate cup fungi and morels)
- Include plant pathogens, decomposers, and symbionts
- Reproduce asexually by enormous numbers of conidia

General Characteristics of Fungi

Diversity:
- Essential for terrestrial ecosystems (break down organic material and recycle nutrients)
- 100,000 described species, estimated 1.5 million total species
Nutrition:
- Heterotrophs, absorb nutrients from outside their body
- Use enzymes to break down complex molecules into smaller organic compounds
- Diverse lifestyles (decomposers, parasites, mutualists)
Morphology:
- Multicellular fungi with mycelia (networks of branched hyphae) for absorption
- Fungal cell walls contain chitin
- Most fungi have septate hyphae with pores for cell-to-cell movement of organelles
- Coenocytic fungi lack septa and have a continuous cytoplasmic mass with multiple nuclei

Specialized Hyphae

Some fungi have hyphae specialized for capturing prey
Some fungi have haustoria that penetrate host tissues
Mycorrhizal fungi deliver phosphate ions and minerals to plants
Types of mycorrhizae: ectomycorrhizal fungi (do not penetrate root cells) and arbuscular mycorrhizal fungi (penetrate root cells)

Characteristics of Fungi

Fungi are eukaryotes with cells that have a nucleus and membranous organelles.
There are approximately 100,000 named species of fungi, but scientists believe there may be around 1.5 million different species on Earth.
The largest known organism is a fungus, covering over 2,000 acres of land and estimated to be 3,000 years old.

Nutrition and Digestion

Fungi are heterotrophic, obtaining nutrients by breaking down and absorbing organic matter.
They absorb nutrients through their plasma membrane, unlike animals, which ingest their food.
Digestion occurs both outside and inside fungal cells.

Lifestyles of Fungi

Decomposers break down organic matter.
Parasitic fungi benefit at the expense of another organism.
Mutualistic fungi provide benefits to their host and receive benefits in return.

Body Structure

A fungus's body is called a mycelium, composed of thread-like filaments called hyphae.
Hyphae are too small to be seen with the naked eye and are often hidden underground or inside dead trees.
Visible parts of fungi, such as mushrooms, are only the reproductive structures.

Cell Walls and Chitin

Fungal cell walls are composed of chitin, a unique characteristic among organisms.
Chitin is also found in the exoskeletons of arthropods, such as crabs and insects.

Types of Fungi

Septate fungi have partial divisions between their nuclei, with dividers called septa.
Coenocytic fungi lack these dividers and have a single, large cell containing many nuclei.
Specialized forms of fungi have modified hyphae for trapping prey or forming associations with plants.

Mycorrhizae

Mycorrhizae is a symbiotic relationship between fungi and plant roots.
There are two types: ectomycorrhizae, which only penetrate the spaces between cells, and endomycorrhizae, which penetrate the cell walls.
Both types form a mutualistic relationship, with the fungus collecting water and providing it to the plant, and the plant providing sugars and amino acids to the fungus.

Fungi Overview

The golden mushroom in Oregon is one of the oldest living organisms on earth and the most massive.

Fungal Reproduction

Fungi can engage in both sexual and asexual reproduction.
In sexual reproduction, fungi use pheromones to attract a mate in dark environments.
When two fungi mate, their cytoplasm joins, and their nuclei form a dikaryon, which can last from hours to centuries.
Eventually, the nuclei fuse, forming a zygote, the only diploid stage in the fungal life cycle.

Zygote Stage

The zygote is the only diploid stage in the fungal life cycle.
The zygote undergoes meiosis, halving the number of chromosomes, to form haploid spores.

Asexual Reproduction

In asexual reproduction, mycelium produces spore-modifying structures or spore-producing structures using haploid nuclei.
These structures produce haploid spores through mitosis.
Examples of asexual reproduction include:
- Penicillin mold growing on orange surfaces
- Molds producing large amounts of spores
- Yeast cells reproducing through budding
Asexual reproduction allows fungi to quickly reproduce when resources are abundant.

Yeast Cells

Yeast cells are single-cell organisms and an exception to the rule that fungi are multicellular.
During budding, a mature yeast cell produces an outgrowth that eventually becomes a new cell, making yeast cells briefly multicellular.

Characteristics of Basidiomycota

Known as club fungi due to the club-like structure of the basidia
Most edible mushrooms belong to this phylum
Includes bioluminescing mushrooms

Basidia and Spores

Basidia: structures where spores are found, can be singular or plural
Gills: reproductive structures, not for respiration; found in mushrooms
Hundreds of gills in each mushroom, containing basidia and spores
Basidiospores created through meiosis in the basidia

Life Cycle Stages

Hyphae: underground, haploid, and of opposite mating types
Fusion of hyphae creates a diploid structure
Basidio carp: reproductive body growing above ground
Basidia on the gills produce spores through meiosis
Four haploid, single-celled basidiospores created in each basidia
Spores released into the environment; can grow into new hyphae under suitable conditions

Important Terms

Basidio: refers to the reproductive body
Carp: entire structure growing above ground
Basidia: club-like structure where spores are found (singular or plural)
Basidiospor: spores created in the basidia
Meiosis: process of basidiospore creation in the basidia

Characteristics of Ascomycota

Referred to as the sac fungi
Spores are held in a structure called an ascus

Examples of Ascomycota

Truffles
Morel mushrooms
Cup fungi

Sexual Reproduction in Ascomycota

Hyphae (haploid) grow and touch, forming an ascocarp (diploid)
Ascocarp grows into a visible fungus
Meiosis occurs in an ascus within the ascocarp, producing eight ascospores in each ascus

Key Structures in Ascomycota

Ascocarp: the reproductive structure in Ascomycota
Ascus: the spore-making structure within the ascocarp where meiosis occurs

Life Cycle of Ascomycota

Hyphae of opposite mating types come together and form an ascocarp
Ascocarp grows into a visible fungus
Meiosis occurs in the ascus, producing ascospores
Ascospores are released into the environment
Ascospores grow into hyphae in suitable conditions, restarting the cycle

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the characteristics and features of fungi belonging to the phyla Chytridiomycota and Zygomycota, including their habitats, life cycles, and unique features.