Chapter 31: Fungi Flashcards
What supergroup and subgroup are fungi in?
Unikonta
- Opisthokonts
True or False:
Fungi are autotrophs
False, they are heterotrophs
Meaning they feed on organic matter produced by other organisms
List characteristics of the kingdom Fungi
- Have a cell wall composed of chitin
- Single/multicellular
- Chemoorganotrophs
- Dispersed by means of spores
- Bodies are constructed or hyphae
What are some important ecological roles of fungi?
- Decomposers
- Mutualists
- form mycorrhizal associations with 80% of plants
- Pathogens
What is hyphae?
The individual filaments that make up the body of a mycelium
What are the two types of fungi?
- Single-celled
- yeasts
- Multicellular filaments
- mycelia
What is mycelium?
The root looking part of a fungus (the underground part)
- web of hyphae
How do fungi eat?
Their hyphal tips secrete enzymes that break down the substrate and absorb it
- products diffuse back into hyphae - fungi grows through its food
What enhances feeding by absorption for fungi?
Chitin in their cell walls
What other features do fungi have that aid in food absorption?
- Large surface area/volume
- Ability to break down cellulose and lignin
During absorptive feeding, what role does the nucleus play?
The nucleus hangs back (stays away from the very tip of the hyphae) and directs the movement
How does a large surface area aid in absorptive feeding?
It’s easier for food to get through a larger surface area of skin
Digestion and absorption for fungi occurs _________.
extracellularly (occurs outside of the cell)
What are the two forms of hyphae and what are their differences?
- Septate hypha
- hyphae are divided into cells by septa
- the septa have pores for nutrients and organelles to flow from cell to cell
- Coenocytic hypha
- hyphae have no dividing walls
- thousands of nuclei
Mycelia are the ________ ______ ________ of fungi
ecologically active bodies
Are mycelia rigid or elastic?
Both, they are mostly rigid but their tips are elastic so that they can stretch to find food
True or False:
Mycelia have a huge surface area
True
What is the mushroom?
A fruiting body for reproduction
How many spores make up a mycelium?
One, an entire web of mycelium grows from one spore
Fungi are saprophytes. What does saprophyte mean?
An organism that feeds on dead or decaying matter
Fungi are symbionts. What does symbiont mean?
A mutually beneficial relationship between a fungus and another organism
What are mycorrhizal associations?
Symbiotic relationship between a fungus and a plant’s roots
Fungi are parasites. What does parasite mean?
An organism that feeds on the living tissue of a host
Parasites that cause disease are called ________.
pathogens
What is enzyme induction?
When fungi only produce digestive enzymes that are required for the substrate they’re trying to absorb
How do fungi absorb their food if ammonia and glutamine are present in the environment?
Fungal enzymes usually take up nitrates and turn them into ammonia to use.
However, if ammonia and glutamine are already present in the environment, they repress the fungal enzymes and the fungi uses them instead to aid in absorption.
How do fungi absorb their food if glucose is present in the environment?
Fungal enzymes usually absorb sucrose, maltose and galactose.
However, if glucose is already present in the environment it will repress the fungal enzymes and the fungi just uses glucose instead.
Explain how some fungi are predators
Some fungi have hyphae that are adapted for trapping prey.
For example, there is a fungi who’s hyphae forms hoops that trap nematodes and the fungi slowly breaks them down and absorbs them.