Chapter 29 Flashcards
Fungi
What type of heterotrophs are fungi?
They are heterotrophs. Fungi also decomposers and symbionts.
How are fungi related to animals?
Fungi are much more closely related to animals than to land plants.
Why are fungal infections in humans difficult to treat?
Drugs that affect fungal physiology are likely to damage humans.
What key traits link animals and fungi?
- DNA sequencing data 2. Both synthesize chitin 3. Similar flagellates in chytrid spores and gametes 4. Both store glucose as glycogen.
What are microsporidians?
Single-celled, parasitic eukaryotes that are classified as fungi.
What is known about chytrids and zygomycetes?
Both are fungi.
Chyrids-Most chytrids are aquatic, living in freshwater or marine environments.
Zygomycetes- Mostly terrestrial, found in soil and decaying plant and animal matter.
What is the hypothesis regarding the earliest fungi?
The earliest fungi were aquatic and then switched to terrestrial life early in their evolution.
What are the two forms of fungi?
- Single-celled forms (yeast) 2. Multicellular filamentous forms (mycelia).
What are mycelia?
Branching networks of very thin hyphae that provide a large surface-area-to-volume ratio for efficient nutrient absorption.
How do mycelia behave?
They constantly grow towards food sources and die back where food is scarce.
What type of relationship do fungi and land plants often have?
They often have a symbiotic relationship.
What are the types of symbiosis?
- Mutualistic 2. Parasitic 3. Commensal.
What are mycorrhizae fungi?
Fungi that form symbiotic relationships with plant roots to help absorb nitrogen, phosphorus, and water.
What are endophytes?
Organisms that live between and within plant cells, often in close association with roots or aboveground tissues.
What type of digestion do fungi perform?
Fungi perform extracellular digestion.
What are the two most abundant organic molecules that fungi can digest?
Lignin and cellulose.
What role do saprophytic fungi play after plants die?
They degrade lignin and cellulose in wood and use nutrients from decaying plant material.
What is lignin?
An extremely strong, complex polymer found in the secondary cell wall of plant vascular tissues.
What is cellulose?
A polymer of glucose found in the primary and secondary cell walls of all plant cells.
How do fungi affect the carbon cycle?
They speed up the carbon cycle in terrestrial ecosystems by freeing up carbon atoms locked in wood.
What is the purpose of fungi reproduction?
To promote genetic diversity in offspring.
What are the two steps of fungi fertilization?
- Fusion of hyphae 2. Fusion of nuclei from the fused hyphae.
How does asexual reproduction occur in fungi?
A haploid mycelium produces spore-forming structures, and spores are generated by mitosis, resulting in genetically identical offspring.
What significant contribution do fungi provide to medicine?
Fungi provided many of our antibiotics.
