Mycologist ______Date ______

Fungi PowerPoint Notes

•What Are Fungi?

–Many fungi feed by absorbing nutrients from decaying matter in the soil. Others live as parasites, absorbing ______from their hosts.

–The cell walls of fungi are composed of ______, a polymer made of modified sugars that is also found in the external skeletons of insects.

–The presence of chitin is one of several features that show fungi are more closely related to ______than to plants.

•Structure and Function

–Yeasts are tiny fungi that live most of their lives as ______cells.

–Mushrooms and other fungi, on the other hand, grow much larger. Their bodies are made up of cells that form long, slender branching filaments called ______.

–In most fungi, cross walls divide the hyphae into compartments resembling cells, each containing one or two ______. In the cross walls, there are openings through which cytoplasm and organelles can move.

–The body of a mushroom is actually the ______body, the reproductive structure of the fungus.

–The fruiting body grows from the ______, the mass of branching hyphae below the soil. Clusters of mushrooms are often part of the same mycelium, which means they are part of the ______organism.

•Reproduction

–Fungi can reproduce ______, primarily by releasing spores that are adapted to travel through air and water.

–Breaking off a hypha or ______off a cell can also serve as asexual reproduction.

–Most fungi can also reproduce ______. The life cycle of the bread mold Rhizopusstoloniferis shown.

–Sexual reproduction in fungi often involves two different mating types. One mating type is called “+” (______) and the other “–” (______).

–Hyphae of opposite mating types fuse together, bringing + and – nuclei together in the same cell.

–The + and – nuclei form pairs that divide as the mycelium grows. Many of the paired nuclei fuse to form diploid ______within a zygospore.

–The ______germinates and a sporangium emerges.

–The ______reproduces asexually, releasing haploid spores produced by meiosis.

–Each spore has a ______combination of parental genes, and each can make a new mycelium.

•Diversity of Fungi

–More than ______species of fungi are known. Biologists have placed fungi into several distinct groups.

–The major groups of fungi differ from one another in their ______structures.

•Decomposition

–Many fungi feed by releasing ______enzymes that break down leaves, fruit, and other organic material into simple molecules. These molecules then diffuse into the fungus.

–Many organisms remove important trace elements and nutrients from the soil. Fungi ______these essential elements and nutrients. If these materials were not returned, the soil would quickly be depleted.

•Parasitism -Parasitic fungi can cause serious diseases in plants and animals by disrupting ______.

•Plant Diseases

–A number of parasitic fungi cause diseases that threaten food crops. Corn smut, for example, destroys corn kernels.

–Some ______, which infect a wide variety of plants, are also fungi.

•Animal Diseases

–Parasitic fungi can also infect ______.

–The fungus that causes athlete’s foot forms a mycelium in the outer layers of the skin, which produces a red, inflamed sore from which the spores can easily spread from person to person.

–The yeast Candida albicansis often responsible for vaginal yeast infections and for infections of the mouth called ______.

•Lichens

–A lichenis a ______association between a fungus and a photosynthetic organism. The photosynthetic organism is either a green alga or a cyanobacterium, or both.

–Lichens are extremely ______to drought and cold. Therefore, they can grow in places where few other organisms can survive—on dry bare rock in deserts and on the tops of mountains.

–Lichens are able to survive in these ______environments because the green algae or cyanobacteria carry out photosynthesis, providing the fungus with a source of energy, while the fungus provides the green algae or cyanobacteria with water and minerals.

–Lichens are often the ______organisms to enter barren environments, gradually breaking down the rocks on which they grow. In this way, lichens help in the early stages of soil formation.

–Lichens are also remarkably sensitive to air ______: They are among the first organisms to be affected when air quality deteriorates.

•Mycorrhizae

–Fungi also form ______relationships with plant roots. These symbiotic associations of plant roots and fungi are called mycorrhizae.

–Researchers estimate that ___ to ___ percent of all plant species form mycorrhizae with fungi.

–The hyphae collect water and minerals and bring them to the roots, greatly increasing the effective ______area of the root system. In addition, the fungi release enzymes that free ______in the soil.

–The plants, in turn, provide the fungi with the ______of photosynthesis.

MAJOR GROUPS OF FUNGI

Common Name / Characteristics
Basidiomycota
Zygomycota
Chytridiomycota
AM Fungi
Ascomycota
Lichens