Test 3 - Protists & Fungi

2025-07-18

What domain are protists in?

Eukarya

Describe protist cells and structures (3).

• Nucleus & organelles

• unicellular or multicellular

• some colonial (loosly attached w/independent function) (e.g. Diatoms)

What does protista mean, and why?

the first, because they are the first eukaryotes.

When did the first protists evolve?

1.7 billion years ago

What are protozoans (5)?

• phylum of protista

• polyphyletic group (different ancestors; taxonomically inappropriate) (outdated)

• single-celled eukaryotes

• free-living or parasitic

• feeds on organic matter

How did the first protozoans evolve?

endosymbiosis

Where do protists live (3)?

freshwater, marine, moist terrestrial habitats

What role do protists play in marine and freshwater systems?

food for animals

What are mutualists and how are protists mutualists?

• two parties mutually benefitted

• Zooxanthellae lives in coral & photosynthesizes, making sugars. Coral uses those sugars for energy, & provides the protist with protection and nutrients.

Describe an example of a parasitic protist.

lives in bloodstreams of host causing malaria, amoebic dysentery, giardiasis (intestinal illnesses)

Describe animal-like (protozoa) protists (3).

• ingestive;

• heterotrophic;

• digests food in lysosomes (vacuoles w/digestive enzymes)

Describe plant-like (algae) protists (2).

• photosynthetic;

• autotrophic;

Describe fungus-like (slime molds) protists (2).

• absorptive

• heterotrophic

Name three ways protists move.

• cilia (tiny hair)

• flagellum (in liquids)

• pseudopodia (false foot)

How are three ways protists can reproduce sexually? Describe this process.

1. Syngamy: 2 haploid gametes → 1 diploid zygote

   • gametes released

   • fusion of cytoplasm (plasmogamy)

   • fusion of nuclei (karyogamy)

   • zygote undergoes mitosis to form embryo

2. Conjugation: cytoplasmic bridge → genetics exchange

3. Alternation of Generations: switches between haploid stage (gametophyte)(makes gametes) & diploid stage (sporophyte)(makes spores).

   • Syngamy

   • Meiosis

Describe difference between syngamy and alternation of generations.

syngamy happens during alternation of generations

Describe two ways protists can reproduce asexually.

1. binary fission

2. multiple fission (schizont = nuclei, merozoites = products)

What are eyespots for?

light detection

What is a cyst (protists)?

hardened outershell that forms when conditions are unfavourable, decreases metabolic activity.

How do some protozoans detect & avoid obstacles and harmful chemicals in their environment?

1. Chemical Sensing - receptors on cell surface, senses attractants and repellents which guides them towards or away (chemotaxis).

2. Mechanical Sensing - touching or bumping into them (cilia).

3. eyespots

Why do some freshwater protozoa use contractile vacuoles to pump out excess water?

• made of H2O & salts → H2O outside of protist attracted to salt inside protist

• too much H2O in protists inflates it → pop!

Describe phagocytize (engulfing).

• surrounds with membrane

• forms bubble-like structure around it (vacuole or phagosome).

• enzymes break down

Name three benefits of protists.

1. ecologically important plankton

2. synthesizes oxygen supply

3. break down organic material in digestive systems of termites & wood roaches.

Describe Phylum Sporozoa (plasmodium) (2).

• causes malaria (blood disease caused by plasmodium protozoan parasites transmitted by Anopheles mosquito)

• parasites multiply in liver then destroy red blood cells

Describe 2 diseases that Phylum Zoomastigina (Trypanosoma) causes.

1. African Trypanosomiasis/sleeping sickness

   • infected through infected Tsetse fly bite, into humans & other animals.

   • Causes behaviour change, confusion, sensory disturbances, poor coordination, sleep cycle disturbance.

   • fatal unless treated

2. American Trypanosomiasis/Chagas Disease

   • infected blood-sucking Triatomine bugs (kissing bugs) bites skin

   • bug poops/pees nearby

   • parasites enter through broken skin

   • can lead to sudden death or heart failure (progressive destruction of the heart muscle & nervous system)

What is Ciliophora? Describe them (4)

Protists with cilia: Paremeciums

• Complex cells: 2 nuclei (Macronucleus (everyday functions) Micronucleus (reproduction))

• Phagocytosis feeding

• Reproduces by binary fission or conjugation

• mostly aquatic (freshwater/marine)

What is Sarcodina/Amoebozoa ? Describe them (6).

Protists with pseudopodia:

• Phagocytosis feeding

• soft & shapeless

• unicellular

• aquatic (freshwater, marine, moist soil)

• free-living or parasitic

• mostly binary fission

What is Euglenophyta? Describe them (7).

Protists that are both plant-like & animal-like:

• Mixotrophic (dual nutrition) (photoheterotroph)

• flagella

• eyespot

• pellicle (flexible outer layer of protein) instead of cell wall

• unicellular

• freshwater

• mostly binary fission

What is Pyrrophyta? Describe them (7).

Marine protists known for bioluminescence, armored cell walls, and role in red tides:

• 2 flagella

• Cell wall of cellulose plates

• autotroph or photoheterotroph

• bioluminescent (glow in the dark whehn disturbed)

• red tides (harmful algal blooms (excess N2&P)(toxins))

• surface of saltwater/freshwater

• asexual, but sexual under stress

What is Rhodophyta? Describe them (6).

Red Algae:

• red pigment (allows blue & green light absorption, which penetrates deep waters allowing them to photosynthesize better)

• multicellular

• warm coastal waters; attached to rocks or reefs

• no flagella

• cell walls contain carrageenan or agar

• alternation of generations

What is Myxomycetes? Describe them (4).

Plasmodial slime molds:

• Plasmodium stage (life cycle): multinucleate (many nuclei not divided into separate cells) slowly moves by cytoplasmic streaming to hunt for bacteria, fungi, and organic material

• phagocytosis feeders

• damp environments

• in harsh conditions: forms fruiting bodies that produce spores. Spores grow amoeba-life and fuse to become a new plasmodium

Scientific name of paramecium?

Paramecium aurelia, Paramecium bursaria, etc

Scientific name of amoeba?

Amoeba proteus

Scientific name of Euglena?

Euglena gracilis, Euglena viridis, etc

Are paremecium unicellular, colonial or multicellular?

unicellular

Are amoeba unicellular, colonial or multicellular?

unicellular

Are euglena unicellular, colonial or multicellular?

unicellular

Are slime molds unicellular, colonial or multicellular?

• Plasmodial slime molds (Myxomycetes), technically unicellular

• Cellular slime molds (Dictyostelids), usually unicellular, multicellular when food is scarce.

Are paremecium animal-like, plant-like, or fungus-like?

animal-like

Are amoeba animal-like, plant-like, or fungus-like?

animal-like

Are euglena animal-like, plant-like, or fungus-like?

plant-like

Are slime molds animal-like, plant-like, or fungus-like?

fungus-like

How does paremecium move?

cilia

How does euglena move?

flagella

How does amoeba move?

pseudopodia

How does a slime mold move?

cytoplasmic streaming or pseudopodia

Are paremecium mutualitis or parasitic and why?

mutualistic with algae (algae photosynthesizs and shares nutrients, Paramecium protects and moves)

Are amoeba mutualitis or parasitic and why?

depends on species, amoebic dysentery = bad, digests cellulose for termites = good.

Are euglena mutualitis or parasitic and why?

neither

Are slime molds mutualitis or parasitic and why?

neither, breaks down dead material

How was fungi considered back in the day..?

• Subsection of plantae

• Unimportant in ecological roles

• Useless

How are fungi important?

• breaking down dead organic material

• Symbiotic relationship with plants

• Production of drugs, food, & alcoholic beverages

Give six types of things that fungi make.

Bread mold, moldy cream cheese, alcoholic beverages, rotten bananas, athletes foot, cheese

What is the study of fungi called?

Mycology

How are fungi classified?

Structure & reproduction method

Name 8 characteristics of fungi.

• eukaryotic

• Absorptive chemoheterotrophics (no ingestion, absorbs through cell walls & membrane)

• Saprophytic (food from decaying organic matter by secreting enzymes)(decomposers)

• Parasitic

• Mutualistic (provides water, increase surface area for absorption by root of host (mycorrhizae))

• Non-motile

• Can be predacious (mycelium trap)

• Pioneer organism (1st to grow in barren environment)

Describe the three typical fungi structures.

1. Spores: circular, gives rise to hyphae

2. Hyphae: individual branching filaments

3. Mycelium: thick tangled hyphae, underground portion of fungus

Name and describe four types of hyphae.

1. Rhizoid (rhyzomorphs): root-like, penetrated food (anchor fungus to release enzymes for digestion)

2. Stolons: stem-like, surface of food

3. Sporangiophores: pushed into air, contains sporangia (top of specialized hyphae)

4. Mycelium: thick mass of hyphae that make up the body of fungus

Name three ways fungi reproduce asexually.

• when conditions are favorable

• Spores (sporangia spread by wind, needs proper combination of temperature, moisture, food, to germinate)

• Fragmentation

• Budding (yeast)

How to tell if the organism is male or female?

• smalls gametes = male

• Big gametes = female

Describe two ways fungi reproduce sexually.

1. Alternation of generations: mating type (+) and (-) fuse, no gender.

2. Conjugation

What are Zygomycota?

Phylum, common mold. Black bread mold that reproduces using resistant zygospores.

What are Ascomycota?

Phylum, sac fungi. Baker’s yeast that reproduces by budding and forms spores in asci.

What is Basidiomycota?

Phylum, club fungus. Common mushroom that produces spores on club-shaped basidia.

What is Deuteromycota?

Phylum, imperfect fungi. Fungus without a known sexual stage, source of penicillin.

What is Chytridomycota?

Phylum, chytrids. Water-dwelling fungus with flagellated spores that infects amphibians.