Protista and Fungi Notes

Eukaryotes - Kingdom Protista and Kingdom Fungi

Eukaryotic Cell Characteristics

• Nucleus: Eukaryotic cells have a nucleus.

• Membrane-bound organelles: Eukaryotic cells contain membrane-bound organelles.

• Size: Eukaryotic cells are generally larger than prokaryotic cells.

Kingdoms within Domain Eukarya

• Protista

• Fungi

• Plantae

• Animalia

Endosymbiotic Theory

• Summary: A larger prokaryote engulfed a smaller prokaryote, living symbiotically and dividing as one. The smaller prokaryote eventually became an organelle.

Kingdom Protista

General Characteristics

• Considered the first eukaryotic organisms.

• Reproduction: Asexual and sexual reproduction methods are observed.

• Cellularity: Unicellular or multicellular organisms.

• Nutrition: Autotrophic or heterotrophic.

Nickname: "Junk Drawer Kingdom"

• Appropriate because some organisms don't fit neatly into the other three kingdoms.

Classification Based on Nutrition

• Plant-like protists (autotrophic)

• Animal-like protists (heterotrophic)

• Fungus-like protists (saprotrophic)

Animal-Like Protists

Protozoans

• Another name for animal-like protists, meaning "first animal".

• Distinguishing characteristic: Heterotrophic nutrition.

• Movement: Amoebas use pseudopods, while paramecia use cilia.

Plant-Like Protists

Algae

• Plant-like characteristics: Autotrophic photosynthesizers that produce their own food using energy from the sun.

Algal Bloom (Red Tide)

• Cause: Plentiful food and favorable conditions leading to rapid reproduction of dinoflagellates.

• Dangers: Depletes nutrients and oxygen, causing marine organisms to suffocate.

Fungus-Like Protists

Distinguishing Characteristics

• Saprotrophic (decomposers).

• Use spores for reproduction.

• Difference from true fungi: Cell walls are made of cellulose, not chitin.

Examples

• Slime molds

• Water molds

• Downy mildew

Kingdom Fungi

Defining Features

• Eukaryotic.

• Heterotrophic.

• Contain hyphae.

• Fungal cell walls are made of chitin.

• Multicellular (except for yeasts, which are unicellular).

Hyphae

• Threadlike filaments that make up the body of a fungus.

Mycelium

• Net-like mass of branching hyphae, typically found underground.

Advantage of Filamentous Body

• Increases surface area for nutrient absorption.

Fruiting Body

• The reproductive structure of a fungus seen above ground.

Energy Acquisition

• Fungi digest then ingest

• Type of heterotroph:

  • Saprophytes: Feeds on dead organism or organic wastes.

  • Parasites: Absorbs nutrients from living cells. Example: Athlete's Foot, Ringworm.

  • Mutualistic Fungi: Mycorrhizae shows close relationship with other plant. Example: roots of soybean species.

Fungal Reproduction

Asexual Reproduction

• Budding: Yeast cells develop new cells that pinch off from the parent cell.

• Fragmentation: Mycelium is physically broken apart and begins to grow.

• Spore production: Spores are used in both asexual and sexual life cycles.

Spores

• Key to sexual reproduction.

• Adaptations for survival: Small, lightweight, and have waterproof cell walls.

Fungal Symbiotic Relationships

Lichens

• Mutualistic relationship between fungi and algae.

• Benefits:

  • Fungi provide a dense web for algae to grow.

  • Algae provides usable sugars to Fungi.

  • Lichens are sensitive to environmental change

• Fungi are very resilient

Mycorrhizae

• Fungi that wrap around the roots of certain plants.

• Benefits:

  • Fungus absorbs and concentrates minerals for the plant.

  • Hyphae increase surface area of the root system.

Benefits of Fungi

• Bioremediation.

• Medicines.

• Foods.

Harmful Fungi

• Destruction of plants and crops.

• Parasitic fungi causing infections.