Biology Exam #2: Fungi

When did fossilized fungal evidence arise?

• Silurian Period

• 1 Billion years ago

• Hyphae fossilizes

What are prototaxites?

• one of the first fungal bodies to exist

• was much more humid back then

What is ploidy?

• Plants and fungi have multiple copies of chromosomes

Fungi characteristics

Characteristics similar to animals

• Heterotrophic- Derive energy from organic compounds

• Cells walls made of chitin

• Produce pigments

• store carbs as glycogen

• can absorb nutrients from environment across cell surface

Characteristics similar to bacteria

• They are decomposers

Cell structure and function

• Contain a complex cell structure like other eukaryotic cells

  • Membrane bound nucleus (DNA within)

  • DNA wrapped around histones

  • Mitochondria

  • golgi apparatus, endoplasmic reticulum

  • DONT HAVE CHLOROPLASTS

  • Thick cell walls like plants

Anatomy of fungi

• Mycelium- network of hyphae

  • obtains nutrients, produces fruiting body, mostly underground

• Reproductive structure

  • fruiting body (The mushroom)

  • produces spores

• spores

  • Involved in fungal reproduction

  • produced in fruiting body

  • HAPLOID

    • They germinate when they hit damp soil

Fungal reproduction

• Both sexual and Asexual

• most produce haploid spores that go through mitosis

  • form multicellular haploid organisms

Asexual fungal reproduction

• Budding

  • buldge forms and nucleus divides by mitosis

• Fragmentation

  • Fragment of hyphae grow new colonies

• producing spores

  • genetically IDENTICAL to parent

Sexual

• Genetic VARIATION

• conditions and environment have to NOT be great

  • or else asexual would occur

• Homothallic= Self fertile

How do fungi get nutrients?

• They are heterotrophic

  • They must take in organic molecules to generate energy they need

• Digestion before ingestion

  • Exoenzymes secreted from hypha break down large organic molecules

• obtain nutrients from organic decaying matter

  • saprobes

• They can derive nutrients from host tissue (parasitic)

what type of growth do mose fungi have?

• Multicellular

  • Form hyphae (This is the fuzz we see on tomatoes)

Which mushrooms have a bright red pigment, some of which are poisonous to humans?

• Amanita Muscaria (Fly agaric)

  • Pigments are associated with cell wall

  • Protection against ultraviolet radiation (the pigment)

What habitats do fungi grow best in?

• Moist

• slightly acidic

• both dark and light environments

• Vary in O2 requirements

  • Most need O2

  • Some can be killed by O2

• Most can live anywhere

What molecules are released when fungi breaks down organic material?

• Nitrogen

• Phosphorus

• DIGESTION BEFORE INGESTION

Mutualistic Relationships

• Mycorrhizae

  • about 90% of plant species

  • Ectomycorrhizae= wrap roots in a sheath of hyphae

  • Endomycorrhizae= fungi grow within roots

  • Endophytes= Live within a plant and secrete toxins that help prevent predation and resistance to environ. stress

Are fungi mutualistic?

YES

• Most terrestrial plant roots connect w/ fungi and form mycorrhizae

• Allows exchange of nutrients and H2O to benefit both organisms

Another example of mutualistic relationships

Lichen

• A fungus that lives in a mutualistic relationship w/ a photosynthetic organisms

• neither organisms can live without this relationship

• Very sensitive to air pollution

  • Which means that if the species is there, the air quality is probably good

How do ants and fungi work together?

• Ants maintain a fungal body within their ant colony

• Ants collect leaves to feed the fungal body

• Ants can eat portions of the fungus and byproducts of the fungus

What are fungivores?

Animals that unknowingly disperse fungal spores due to their diet

• PIGS

How do humans benefit from fungi?

• Nutrient cycling

• pest control

  • Humans are heterotrophic as well

• Mycorrhizae relationship to plant growth and agricultural goals

• Foods for human consumption

  • Mushrooms

  • cheese

  • Alcohol

  • Bread

• Medicine

• Clothing