Exercise 8 The Fungi: Yeasts and Molds Flashcards


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1

What does the term "coenocytic" mean?

Coenocytic is a type of fungal mycelium that is not separated into individual cells by cross walls. Cellular organelles, nuclei, and cytoplasmic constituents move freely by cytoplasmic streaming.

2

What criteria are the basic for traditional classification schemes? What modern approach to classification has shown that traditional schemes do not apply?

Fungi have been traditionally classified using morphology and reproductive mechanisms. Modern approaches use genetic analysis which has shown that traditional approaches were not always correct in establishing the taxonomic groupings. However, identification still relies considerably on morphology.

3

What unique compound is found in the cell walls of fungi but is absent in plant cell walls?

Fungi contain chitin in their cell walls whereas plants contain cellulose

4

What is one of the fungi that is responsible for infections of skin and nails?

The genus Trichophyton causes many infections in humans associated with hair, skin, and nails

5

What does the term "dimorphic" refer to? Give an example of an organism that is dimorphic and what disease it causes.

Dimorphic refers to fungi that grow as yeast forms in tissue and reproduce by budding, but produce mycelium and sporulation structures when grown in nutrient medium. Histoplasma capsulatum is an example of a dimorphic fungus.

6

How do zygospores differ from conidiospores?

WHAT IS THE DIFFERENCE BETWEEN SEXUAL AND ASEXUAL SPORES? Conidiospores are asexual spores that form on specialized hyphae called conidiophores. Sporangiospores are asexual spores that develop inside sporangia. Asexual means geneticially identical, with many spores being developed. Sexual spores form by the fusion and genetic exchange between genetically distinct hyphae.

7

What foods are produced by fungi?

Fermentation by yeasts produce fermented beverages such as beer and wine. Yeasts are also used in bread making, which is a fermentation process. Fungi are important in producing cheeses such as blue cheese and Roquefort. Mushrooms are used in a variety of foods such as pasta and pizza.

8

Why might fungi have been theorized to be involved in the Salem witch trials?

The fungus Claviceps can infect grain, producing ergot alkaloids that are hallucinogenic. Some of the people involved in the Salem witch trial displayed symptoms characteristic of ergot poisoning that could have come from bread made with infected grain.

9

What are mycotoxins? In what popular food might they be found?

Mycotoxins are toxins that are carcinogens, i.e., cause cancer. They occur in peanuts and grains infected with fungi.