MICB 3031 - Lecture 15 Protists and Fungi Exam 3

What are the general characteristics of fungi?

Fungi belong to Domain Eukarya and Kingdom Fungi.

• range from unicellular yeasts to large multicellular organisms

• lack chlorophyll

• cell walls made of chitin (Polymer N-Acetylglucosamine)

• has plasma membranes

How do fungi obtain nutrients?

Fungi are absorptive heterotrophs. They secrete enzymes to break down organic material and absorb the released nutrients.

Fungi that obtain nutrients from dead and decaying organic matter

Saprophytes

Why are fungi important decomposers?

They break down complex organic compounds, including cellulose, and recycle nutrients. Without fungi, dead plants and trees would accumulate.

Mycoses

Diseases caused by fungi

Mycotoxicosis

Poisoning by fungi

What are aflatoxins?

• Carcinogens

• Intercalate between DNA bases, cause mutations

• Ex: Aspergillus

What are Ergot Alkaloid?

• LSD Structure

• Cause delusions and convulsions

• Used to treat migraines and induce labor

• Claviceps

What are the main types of symbiotic relationships involving fungi?

Lichens = fungi associate with cyanobacteria;

mycorrhizal fungi associate with plant roots.

What are mycorrhizal fungi?

Fungi that live in plant roots

• Help plants absorb water and nutrients

• Plants provide carbohydrates to the fung

What are the general characteristics of yeasts?

Yeasts are unicellular fungi.

What are the main characteristics of Saccharomyces cerevisiae?

A yeast used in bread making and the production of beer and wine

Based off of these characteristics name the genus and species:
A yeast used in bread making and the production of beer and wine

Saccharomyces cerevisiae

What are the main characteristics of Candida albicans?

A yeast that can be part of normal human microflora in the mouth, vagina, and intestinal tract; it can cause infections such as thrush.

Based off of these characteristics name the genus and species: A yeast that can be part of normal human microflora in the mouth, vagina, and intestinal tract; it can cause infections such as thrush.

Candida albicans

What are the main characteristics of Candida auris?

A drug-resistant yeast

• Urgent threat

Based off of these characteristics name the genus and species:

A drug-resistant yeast

• Urgent threat

Candida auris

What are the general characteristics of molds?

Molds are multicellular fungi made of threadlike structures called hyphae.

What are hyphae and mycelium?

Hyphae are the filaments that make up a mold; mycelium is the mass of hyphae.

What is the difference between septate and aseptate hyphae?

Septate hyphae have cross walls, while aseptate hyphae lack cross walls.

What is a yeast-to-mold (YM) shift?

The ability of some fungi to change between yeast and mold forms.

What are the main characteristics of asexual fungal reproduction?

Offspring are genetically identical to the parent

What are the three mechanisms of asexual fungal reproduction?

• Binary Fission

• Budding

• Spore production

  • Conidiospores

  • Sporangiospores

Whats a unique characteristic about budding?

Can have bud scar where new buds can’t form from it

What are the main characteristics of sexual fungal reproduction?

It often occurs under stress or limited nutrients.

• Opposite mating types (+ and -) fuse,

• genetically varied offspring

• Pheromones allow opposite mating types to signal to one another.

What is a dikaryon?

A single hypha containing two distinct nuclei.

What happens after hyphal fusion during fungal sexual reproduction?

The two nuclei can fuse to form a diploid zygote; meiosis then produces haploid spores.

What are examples of sexual fungal spores?

Zygospores and ascospores.

What does the process of fungi sexual reproduction look like?