Homework 10: Ch. 31 Fungi

Cup fungi are in the phylum _____.

-ascomycota cup fungi are a type of sac fungus.

This diagram shows the structure of a multicellular fungus, with an expanded view of two types of hyphae. Identify the structures and determine which hypha is septate and which is coenocytic. (Note that although this diagram shows the two types of hyphae, a fungus can have either one type or the other, but not both.)

a. mycelium b. pore c. septum d. septate hypha e. coenocytic hypha the body of a multicellular fungus consists of a network of hyphae, which form an interwoven mass called a mycelium. Some hyphae, called septate hyphae, are divided into cells by crosswalls, or septa. Coenocytic hyphae do not have septa; these hyphae consist of a continuous cytoplasmic mass that contains many nuclei and organelles.

The following statements describe something about the body structures or functions of fungi. Identify those statements that are correct.

-Mycelia are made up of small-diameter hyphae that form an interwoven mass, providing more surface area for nutrient absorption. -Some fungi can grow as either filamentous or single-celled forms. -Some fungi secrete digestive enzymes into the environment and then absorb the digested nutrients. -All fungi are heterotrophs; some species live as decomposers and others as symbionts. all fungi are heterotrophs. Most obtain carbon compounds by decomposing organic matter, while others live in a symbiotic association with other organisms. The feeding structure of a multicellular fungus is the mycelium, which consists of numerous small-diameter filaments, or hyphae. Nutrients absorbed by the hyphae can flow throughout the mycelium in both coenocytic hyphae and septate hyphae.

Plasmogamy is indicated by the letter _____.

-b plasmogamy is the fusion of hyphae.

Where does meiosis occur in a mushroom?

-basidia basidia are specialized cells in the gills of a mushroom in which haploid nuclei fuse in preparation for meiosis.

The process indicated by the letter _____ produces a diploid structure.

-c karyogamy produces a diploid zygote.

Most fungi are _____.

-decomposers fungi obtain nutrients from nonliving organic matter.

Karyogamy produces a _____.

-diploid zygote karyogamy is the fusion of nuclei.

True or false? In most fungi, fertilization is complete after the cells fuse together.

-false in most fungi, fertilization is a two-step process consisting of the fusion of cells and then the fusion of nuclei in the fused cells.

Fungi produce _____ spores.

-haploid

Which of the following events occurs first in the development of a spore into a mature mushroom?

-hyphae are produced by mitosis. the spore undergoes mitosis to produce hyphae, which then form a filamentous network called a mycelium.

Basidia produce spores by a process known as _____.

-meiosis

Which structure is not directly involved in the reproduction of at least one major group of fungi?

-mycelium a mycelium is a network of filaments that forms the body of a fungus

Which structure allows the growing mushroom to nourish itself?

-mycelium the mycelium is a mass of filaments with a high surface-area-to-volume ratio, which allows for efficient nutrient absorption.

Which term describes the fusion of cytoplasm from two individuals?

-plasmogamy

Fungi release digestive enzymes into their _____.

-surroundings fungi then absorb the digested nutrients.

Which of these contains two haploid nuclei?

-the heterokaryotic stage of the fungal life cycle the heterokaryotic stage is produced by plasmogamy.

True or false? Most of the cells in a mushroom contain haploid nuclei.

-true a mushroom consists mainly of hyphae that are heterokaryotic, which means they have two distinct haploid nuclei per cell; these nuclei may fuse in specialized cells called basidia and become diploid in preparation for meiosis and spore production.

Most fungi are decomposers; they recycle the nutrients from nonliving organic matter. Other fungi are specialized to live in symbiotic relationships with other organisms. Some fungi live as parasites and others as mutualists. Most plants, in fact, could not survive and grow without their fungal partner. This table lists some examples of different fungal strategies for obtaining nutrients. Sort the following fungi based on whether they are decomposers, mutualists, or parasites.

DECOMPOSER -fungi in association with a fallen log -fungi in association with a dead rabbit -coprophilous fungi MUTUALIST -mycorrhizal fungi on pine tree roots -fungi in the family Lepiotaceae PARASITE -Trichophyton spp. -Cryphonectria parasitica -Cordyceps spp. -Septobasidium spp. and an individual scale insect infected by fungal hyphae fungi have diverse ecological niches, with most fungi being decomposers. Other fungi exist in mutualistic associations. For example, it is estimated that over 85% of plants have mycorrhizal fungi living on their roots; the fungi provide the plants with inorganic nutrients, while receiving organic nutrients in return. Still other fungi are parasites, causing harm to the organisms they live with.