Chapter 31 Flashcards
Unikonta is?
Fungi and Animals
Fungi and Animals are more closely related than Fungi and Plants from a genetic point of view. (True or False)
True
Fungi produce?
Fungi (especially ascomycetes) produce many substances that we use to protect us from bacteria, fungi, and ourselves
Penicillium chrysogenum
(ascomycete)
penicillin
(anti-bacterial)
Acremonium
(ascomycete)
cephalosporin
(anti-bacterial)
Penicillium griseofulvin
(ascomycete)
griseofulvin
(anti-fungal)
Tolypocladium inflatum
(ascomycete)
cyclosporin (immuno-suppressant)
Many basidiomycete and ascomycete fungi are?
parasites or pathogens on plants and animals:
Mushrooms are a good source of protein (T/F)
True
Cordyceps
(ascomycete)
Huitlacoche
(basidiomycete)
Ustilago maydis (scientific name of Huitlacoche)
Trichophyton sp. and Microsporum sp. are the common cause of ?
athlete’s foot and ringworms.
Shared traits between fungi and animals
both heterotrophic, requiring complex organic molecules, but differ significantly in how they access those molecules
most animal cells are motil and some fungi cells are
cells that swim both use one posterior cilia
cell wall - humans No, but they make ECM
Chitin and proteins. Fungi Yes.
Chitin and proteins
Different methods of accessing complex organic molecules
Animals ingest, then digest their food internally, using the large surface area of the intestines to absorb nutrients.
Fungi, grow their mycelia into their food and secrete enzymes to digest it, then use the large surface area to ingest nutrients.
Plants make their own food using light, gas and minerals, and they must maximize their light-, gas- and mineral-collecting surface area.
cell movement
Fungi and Animal cells swim by “pushing” with a posterior cilia, while almost all other eukaryotes use anterior cilia to “pull” themselves through fluids:
Characteristics of fungi
Vegetative body may be unicellular (yeast) or composed of microscopic threads called hyphae
Cell walls made of chitin
Filamentous mycelium = majority of the fungal body
Individual filaments = hyphae
Why did he say fungi are weird?
their cells have holes in them so they are connected but not connected
Fungi “digest, then ingest”
(The greatest mass of the fungal “body” are the unseen filamentous mycelia that grow into the potential food.)
The tip of the mycelia uses the secretory pathway to deliver enzymes into the food mass.
The enzymes diffuse out and digest the food to simple molecules near the tip of the mycelia.
The mycelia then takes-up the simple molecules, concentrating them in the tip.
The mycelia then uses the food to drive growth of the mycelia deeper into the food mass…
…where the cycle begins again until the whole of the food mass has been digested.
Advantages of the fungal lifestyle
Can grow in any direction, over long distances
Can invade the interior of food substrates with absorptive filaments
Dispersal of asexually-produced spores allows for additional exploration of habitats
Fungi digest well, which is good and bad
Good: Otherwise, the world would fill with the carcasses of dead things (Decomposition/Recycling)
Good: They can help other organisms better digest their food or better access nutrients (Mutualisms with animals, mycorrhizae with plants)
Bad: Some of those things they are trying to digest aren’t dead (yet).
What do fungi do?
Secrete enzymes that break down complex macromolecules:
Most fungi are?
opportunists, they don’t notice (or care) what they are digesting and are only stopped if the organism they are trying to digest can stop them.
Agaricus
(basidiomycete)
“button” or “portabella”
Tuber
(ascomycete)
“truffle”
Cantharellus
(basidiomycete)
“chanterelle”
Lentinula
(basidiomycete)
“shiitake”
Morchella
(ascomycete)
“morel”
Amanita virosa
(basidiomycete)
“destroying angel”
Amanita phalodies
(basidiomycete)
“death cap”
Psilocybe
(basidiomycete)
“magic mushrooms”
We use what function of fungi to make things for ourselves?
the ability of fermentation
What is used to ferment grains and fruits to make breads, beers, wines, etc.
Saccharomyces cerevisiae and some related species
Cacao beans are fermented with the help of what to become chocolate?
many different bacteria and fungi
Sourdough starters contain what in addition to the well-known bacteria (lactic acid bacteria)?
many kinds of fungi
Streaks and patterns in “blue” cheeses are caused by?
Penicillium roqueforti and other species
Fermentation of grains and soybean mash with what is an essential step in making soy sauces?
The fungi Aspergillus and several bacteria
Fungi are classified in 5 main phyla:
defined based on how they produce sexual spores (or other traits in lineages without sex
Chytridiomycota
Zygomycota
Glomeromycota
Basidiomycota
Ascomycota
Chytridiomycota
a early-branching group of aquatic fungi, Aquatic,
flagellated fungi
motile zoospores
use filaments to extract food
found all over as “harmless” decomposers, they have recently become famous for causing a disease in amphibians
- the cause of the wide-spread disease of amphibians called Chytridiomycosis
- Chytridiomycosis infects many amphibians, but has recently decimated frog populations all over the world
Blastocladiomycetes
Uniflagellated zoospores
Allomyces example
- Water mold
- Haplodiplontic life cycle
- Female gametes secrete pheromone to attract male gametes
Zygomycota
loss of cilia,
gain of zygo-spore
Other types of fungi lost the ability to swim, but gained the ability to make a tough, resistant type of spore that could survive the dry environment of land
Zygomycetes are incredibly diverse
Not monophyletic – still under research
Include the common bread molds
A few human pathogens
Zygomycota Reproduction
Sexual reproduction
- Fusion of gametangia.
- Haploid nuclei fuse to form diploid zygote nuclei – karyogamy.
- Develops into zygosporangium in which zygospore develops.
- Meiosis occurs during germination of zygospore.
- Releases haploid spores.
Asexual reproduction more common
- Sporangiophores have sporangia that release spores.
plasmogamy (n+n)
fusion of cells without the fusion of the nuclei
(EVERYTHING BUT THE NUCLEI FUSE)
Karyogamy (2n)
nuclei fuse together
Glomeromycota
fungi that are incredibly helpful to other living things
Glomeromycetes form mutualisms with the roots of land plants (arbuscular mycorrhyzae)
Allow the plant and the fungi to exchange resources and mutually help each other to flourish
These associations are found in most land plants, and in fossils over 460 million years old!
Litter-degrading saprotrophic fugus
digests, breaks down, and ingests for its own growth
Ectomycorrhizal fungus
helps the plant grow
Basidiomycota (toad stool) & Ascomycota (cup-like)
Most fungi are found in 2 clades that form a monophyletic group based upon a unique form of sexual reproduction, can tell the diff between by cap
basidiomycetes are best known for their spore-dispersal organ which is?
the mushrooms
- On the gills of a mushroom there are spore-producing structures called a basidia (BASIDIUM)
-MANY basidia are found on the underside of a macroscopic organ that projects above the ground, e.g. mushrooms
Basidiomycota Reproduction
Karyogamy occurs within basidia
- Only diploid cell in life cycle.
Meiosis follows
The four haploid products are incorporated into basidiospores
zygote stage is very short
Basidiomycota Development
Spore germination leads to the production of monokaryotic hyphae
- Results in a monokaryotic mycelium, or primary mycelium.
Different mating types of monokaryotic hyphae may fuse
- Results in a dikaryotic mycelium, or secondary mycelium.
- Heterokaryotic mycelium.
- Basidiocarps (mushrooms) are ENTIRELY FORMED OF SECONDARY MYCELIUM
Ascomycetes
a cup-shaped organ to disperse spores
make spores in a “sac” called a ascus
Asci are found on the top of a cup-shaped organ
Reproduction in the Ascomycota
Karyogamy occurs within asci
- Only diploid nucleus of life cycle.
Asci differentiate in ascocarp
Meiosis and mitosis follow, producing 8 haploid nuclei that become walled ascospores
Asexual Reproduction in the Ascomycota
Asexual reproduction is very common
- Conidia formed at the ends of modified hyphae called conidiophores.
- Allow for the rapid colonization of a new food source.
- Hyphae are divided by perforated septa.
- Allows cytoplasm to flow along the length of the hypha.
- Later perforations may become blocked.
Yeast
Single-celled ascomycetes
Most reproduce asexually by cell fission or budding
Yeasts can ferment carbohydrates
- Break down glucose into ethanol and CO2.
- Used to make bread, beer, and wine.
- Saccharomyces cerevisiae.
Yeast as a Model in Genetic Research
Yeast is a long-standing model system for genetic research
- First eukaryotes to be manipulated extensively.
- Saccharomyces cerevisiae first eukaryote to have genome sequenced.
- Yeast two-hybrid system has been an important component of research on protein interactions.
- Coccidioides posadasii and C. immitis.
- Cause coccidiomycosis (Valley Fever).
