Protists and Fungi

Protists and Fungi

High School

​

Learning Objectives

• Define and describe the main characteristics of protists and fungi.

• Classify protists based on their methods of obtaining nutrition.

• Identify the three major divisions of fungi and their key features.

• Explain the methods of movement and key structures in various protists.

• Differentiate between the roles of protists and fungi in ecosystems.

Key Vocabulary

​

Protist

A protist is a eukaryote that cannot be classified as an animal, plant, or fungus.

​

Cilia

These are tiny hair-like projections used by some protists for movement and for feeding.

​

Pseudopods

These temporary "false feet" are cell projections used by some protists to move around.

​

Hyphae

Hyphae are the long, branching, filamentous structures that make up a multicellular fungus's body.

​

Phytoplankton

These microscopic marine algae perform photosynthesis and are the base of most aquatic food webs.

​

Mycelium

Mycelium is the vegetative part of a fungus, made of a mass of branching hyphae.

Classification of Protists

​

Animal-like Protists

• ​These protists are called protozoa and are heterotrophs, eating other organisms.

• ​​They are consumers that must ingest food to get their energy.

• ​Most are mobile and can move around to hunt for food.

​

Plant-like Protists

• ​These protists are called algae and are autotrophs, making their food.

• ​​They perform photosynthesis using sunlight, just like plants do.

• ​They are important producers in aquatic ecosystems, forming the food base.

​

Fungus-like Protists

• ​These protists include slime molds and are known as decomposers.

• ​​They absorb nutrients from dead or decaying organic materials in their environment.

• ​They reproduce using spores, which is a characteristic similar to fungi.

Multiple Choice

Based on their method of obtaining nutrition, which group of protists is characterized as being autotrophic and making its own food?

• All protists are heterotrophic

• Animal-like protists (Protozoa)

• Fungus-like protists (Slime Molds)

• Plant-like protists (Algae)

How Protists Move

​

Cilia

• ​Cilia are short, numerous, hair-like projections on the cell's exterior.

• ​​They beat together in a coordinated rhythm to enable cell movement.

• ​This motion also helps to sweep food towards the protist.

​

Flagella

• ​Flagella are longer, whip-like tails used for propelling the cell forward.

• ​​Protists typically have one or just a few of these flagella.

• ​Their movement is a wave-like or propeller motion to create thrust.

​

Pseudopods

• ​Meaning "false feet," these are temporary projections of the cell’s cytoplasm.

• ​​The cell moves by extending a pseudopod and pulling itself forward.

• ​Pseudopods are also used to surround and engulf pieces of food.

Multiple Choice

A protist that is a heterotroph and drifts in the water is known as what?

• Algae

• Zooplankton

• Phytoplankton

• A pseudopod

​

​

Examples of Protists

Paramecium

• It uses tiny hair-like structures called cilia for movement through the water.

• A contractile vacuole collects and removes excess water to maintain internal balance.

• Food is collected using an oral groove, which functions like a mouth area.

Euglena

• It moves by using a long, whip-like structure known as a flagellum.

• It has chloroplasts, which allows it to make its own food through photosynthesis.

• An eyespot helps it sense light, allowing it to move toward it for photosynthesis.

Multiple Choice

Which structure in a Euglena is light-sensitive and helps it move toward light for photosynthesis?

• Cilia

• Oral groove

• Contractile vacuole

• Eyespot

​

​

Characteristics of Fungi

• Fungi are eukaryotic, immobile organisms with a cell wall typically made of chitin.

• Multicellular fungi are made of thin filaments called hyphae that form a mycelium.

• They are heterotrophs, acting as parasites on hosts or as saprophytes on dead matter.

• Reproduction in fungi occurs asexually, often through spores, as well as sexually.

​

Multiple Choice

What are the thin, filamentous structures that make up the body of a multicellular fungus called?

• Spores

• Mycelium

• Hyphae

• Chitin

Classification of Fungi

​

Division Zygomycota

• ​Hyphae are not divided by internal walls called septa.

• ​​Spores are produced inside structures that are called sporangia.

• ​A common example is black bread mold, Rhizopus nigricans.

​

Division Ascomycota

• ​The hyphae in this group are divided by septa.

• ​​Spores are produced in unique sac-like structures called asci.

• ​This group includes unicellular yeast and multicellular Penicillium.

​

Division Basidiomycota

• ​Hyphae in this division are also divided by septa.

• ​​Spores are produced in a club-shaped structure called a basidium.

• ​Common examples from this group include various types of mushrooms.

Multiple Choice

A fungus is observed to be multicellular with hyphae that are divided by septa, and it produces the antibiotic penicillin. To which division does it belong?

• Division Ascomycota

• Division Zygomycota

• It is a type of bread mold.

• Division Basidiomycota

​

Common Misconceptions

Misconception	Correction
All protists are single-celled.	Some protists are multicellular, such as certain types of algae.
Fungi are a type of plant.	Fungi are heterotrophs with cell walls of chitin, not cellulose like plants.
All protists are harmless.	Some protists are pathogenic and cause diseases, such as Giardia lamblia.
Mushrooms are the entire fungus.	The mushroom is the reproductive part; the main body is the underground mycelium.

Multiple Choice

How do the roles of fungus-like protists and plant-like protists differ within an ecosystem?

• Fungus-like protists are producers, while plant-like protists are decomposers.

• Fungus-like protists are decomposers, while plant-like protists are producers.

• Both are parasites that infect aquatic animals.

• Both are primary consumers that feed on bacteria.

Multiple Choice

What is the primary advantage for a Euglena to have both chloroplasts and an eyespot?

• To defend itself against predators in its aquatic environment.

• To move towards light to maximize photosynthesis.

• To locate and consume other smaller organisms for food.

• To expel excess water from the cell and maintain homeostasis.

Multiple Choice

A scientist observes a fungus sample with hyphae that are not divided by septa and that produces spores within a sporangium. Based on this evidence, which conclusion is most accurate?

• The fungus is a type of mushroom, belonging to Basidiomycota.

• The fungus is a unicellular yeast, belonging to Ascomycota.

• The fungus is likely a bread mold, belonging to Zygomycota.

• The fungus cannot be classified without genetic analysis.

Multiple Choice

Considering their method of nutrition, what widespread ecological impact would fungus-like protists (slime molds) and saprophytic fungi have?

• They would cause widespread disease in plant populations, leading to ecosystem collapse.

• They would be essential for recycling nutrients by breaking down dead organic matter.

• They would dramatically increase the amount of atmospheric oxygen through photosynthesis.

• They would become the primary food source for most large aquatic animals.

​

Summary

• Protists are diverse eukaryotes, classified as animal-like, plant-like, or fungus-like.

• Fungi are immobile, heterotrophic eukaryotes with cell walls that contain chitin.

• Both protists and fungi play crucial roles as producers, consumers, and decomposers.

• Some protists and fungi can be beneficial, while others can be pathogenic.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4