notes04b

  • Four kingdoms of eukaryotes:

    • Animalia: AnimalsKingdoms

    • Protista: Simple eukaryotic organisms of Eukaryotes

    • Plantae: True plants

  • Animalia, Plantae, and Fungi are mostly multicellular and show some degree of cell differentiation.

  • Fungi: Various fungi

Fungi Structure

  • Fungi appear as a mass of filaments called hyphae.

    • Hyphae are surrounded by a cell wall made of chitin.

  • A collection of hyphae is referred to as mycelium; for example, fuzzy mold on old food.

Mycelium and Sporocarps

  • In many fungi, hyphae bundle together and form sporocarps (reproductive structures).

  • Fungi are abundant in soils; mycelia can be extensive yet only visible through sporocarps above ground.

  • A fairy ring of mushrooms is produced by a single mycelium.

  • Largest known organism: a fungal mycelium covering 2200 acres found in Malheur National Forest, Oregon.

Yeasts

  • Some fungi do not form hyphae, these are called yeasts.

    • Example: Candida albicans, functions in both hyphae and single-celled stages.

    • This yeast can cause diseases in humans.

Fungal Reproduction

  • Many fungi reproduce sexually:

    • Two hyphae of different mating types join to form a new hypha.

    • One fungus has over 17,000 mating types.

    • This sexual hypha produces spores that develop into new hyphae.

  • Sexual hyphae can produce large sporocarps (e.g., mushrooms).

Types of Sporocarps

  • Various types include:

    • Shelf fungi or bracket fungi

    • Other examples: coral fungi, truffles, puffballs, morels, earthstars, jelly fungi.

  • Fungi Imperfecti: A group of fungi that do not reproduce sexually, includes athlete's foot and ringworm.

Fungal Diseases and Uses

  • Common fungal diseases are annoying but rarely serious.

    • Some fungi can cause severe infections in immunocompromised individuals (e.g., Pneumocystis jirovecii causes pneumonia in HIV/AIDS patients).

  • Useful fungi include yeasts for alcohol production, edible mushrooms, and fungi used in food production (e.g., soy sauce, blue cheese).

  • Fungi produce antibiotics such as penicillin and its derivatives.

Overview of Plants

  • Most plants are photosynthetic with chlorophyll, capturing solar energy.

    • Exceptions include some parasitic plants.

  • Plant cell walls are made of cellulose; mature plant cells often die, leaving only cell walls.

Plant Structure and Types

  • Plants show cell differentiation with various cell types.

  • Majority of plants are autotrophs, utilizing sunlight, water, CO2, and soil nutrients for photosynthesis.

  • Chlorophyll converts light energy into chemical energy.

Photosynthesis Process

  • The process converts CO2 and H2O into glucose (C6H12O6).

    • Glucose can form complex sugars or fuel plant metabolism.

  • Other pigments (e.g., xanthophylls, carotenoids, anthocyanins) may be present.

Plant Cell Walls and Structure

  • Mature plant cells are encased by a rigid cell wall.

  • Lignin links cellulose into a tough network, providing structural integrity.

Growth and Meristems

  • Meristems are regions where cell division occurs leading to plant growth:

    • Apical meristem: adds length to the stem.

    • Lateral meristems: contribute to branching; controlled by hormones from apical meristem (apical dominance).

  • Pruning encourages lateral meristem growth, making bushes bushier.

Plant Classification

  • Two main types of plants:

    • Bryophytes: Non-vascular plants lacking specialized water-transporting tissues; limited growth habitats.

    • Tracheophytes: Vascular plants with specialized cells (xylem for water and phloem for nutrients) to transport resources through the plant.