IAG_24 - Tagged

Chapter 24: Fungi

Visual Connection Questions

  • Q1: A dikaryotic ascus in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores. (True Statement)

  • Q2: A basidiocarp is the fruiting body of a mushroom-producing fungus. (True Statement)

Impact of Symbiotic Fungi on Plants

  • In the absence of symbiotic fungi, especially mycorrhizae:

    • Plants cannot absorb adequate nutrients.

    • This nutrient deficiency stunts plant growth.

    • Adding fungal spores to sterile soil can alleviate nutrient absorption issues.

Review Questions

  • Q4: Polysaccharide in fungal cell walls: Chitin.

  • Q5: Organelle not found in fungi: Chloroplast.

  • Q6: Wall dividing cells in fungal filaments: Septum.

  • Q7: Homothallic mycelium contains: Both mating types during sexual reproduction.

  • Q8: Life cycles of perfect fungi are similar to: Haploid-dominant green algae.

  • Q9: The most primitive phylum of fungi is: Chytridiomycota.

  • Q10: Phylum that produces club-shaped spores: Basidiomycota.

  • Q11: Phylum establishing a symbiotic relationship with tree roots: Glomeromycota.

More Review Questions

  • Q12: Fungi that do not reproduce sexually were classified as: Deuteromycota.

  • Q13: New species introducing genetic diversity via diploid zygote cannot belong to: Glomeromycota.

  • Q14: Close association of fungus with tree roots is called: Mycorrhiza.

  • Q15: Importance of fungi as decomposers: Recycle carbon and inorganic minerals through decomposition.

  • Q16: Elimination of non-mycorrhizal fungi affects nitrogen intake by plants: Nitrogen intake would decrease.

  • Q17: A fungus that climbs trees without nutrient exchange is described as: Commensal.

  • Q18: Fungal infection affecting skin and nails is classified as: Superficial mycosis.

  • Q19: Limited targets for antifungal drugs compared to antibiotics: Human cells are similar to fungi cells.

  • Q20: Yeast as a facultative anaerobe ferments alcohol only when: Atmosphere lacks oxygen.

  • Q21: Advantage of yeast cells to express human proteins: Similar protein modification to human cells.

  • Q22: Fungal insecticides are preferred because: They are safe for human consumption, unlike chemical pesticides.

Critical Thinking Questions

  • Q23: Advantages of asexual and sexual reproduction:

    • Asexual reproduction is quick and efficient under favorable conditions.

    • Sexual reproduction increases genetic variability and adaptations in changing environments.

  • Q24: Comparison of components in plants, animals, and fungi:

    • Cell Wall: Fungi (chitin), Plants (cellulose), Animals (none)

    • Chloroplasts: Animals/Fungi (none); Plants (present)

    • Plasma Membrane: Animals (cholesterol), Fungi (ergosterol), Plants (phytosterols)

    • Food Source: Animals (internal digestion), Fungi (external digestion), Plants (photosynthesis)

    • Polysaccharide Storage: Animals/Fungi (glycogen), Plants (starch).

  • Q25: Importance of mycelium's large surface area:

    • Allows fungi to break down decaying matter extensively.

    • Enables secretion of exoenzymes to decompose material and absorb nutrients efficiently.

  • Q26: Purpose of fleshy fruiting body in basidiomycetes:

    • Attracts animals for spore dispersal, aiding in fungal reproduction.

  • Q27: Body structure and features of perfect fungi varieties:

    • Chytridiomycota (Chytrids): Unicellular/multicellular; aquatic motile spores (flagella); example: Allomyces.

    • Zygomycota (Conjugated Fungi): Multicellular; zygospores; examples: Bread and fruit molds.

    • Ascomycota (Sac Fungi): Unicellular/multicellular; sexual spores in sacs (asci); example: yeasts.

    • Basidiomycota (Club Fungi): Multicellular; spores in basidiocarp (mushroom); examples: mushroom-producing fungi.

  • Q28: Benefits of light protection for photosynthetic partners in lichens:

    • Prevents damage to photosynthetic pigments, enhancing survival in harsh conditions.

Ecosystem Relationships and Impacts

  • Q29: Mutualistic relationship between bark beetles and Ambrosiella fungus:

    • Beetles provide food for their larvae; fungus expands to new trees, benefiting both.

  • Q30: Benefits of arbuscular mycorrhizae for plants in arid climates:

    • Increased water absorption and nutrient uptake via extensive fungal hyphae.

  • Q31: How superficial mycoses can lead to bacterial infections:

    • Breakdown of protective skin layer allows bacteria to invade deeper tissue.

  • Q32: Red Queen Hypothesis and its application to red grapes and Botrytis cinerea:

    • Continuous evolutionary pressure between grapes (prey) and fungi (predator) drives adaptations in response to each other, a balancing act of defense and offense.

  • Q33: Historical challenges in bread-making with wild yeasts:

    • Toxic spores often contaminated dough; modern strains by Louis Pasteur provided reliability.

  • Q34: Effects of broad-spectrum fungicide in forests:

    • Disrupt fungi's role as decomposers, leading to accumulation of organic matter.

    • Carbon cycle: lack of decomposition = decreased CO2 for photosynthesis.

    • Nitrogen cycle: decomposition releases usable nitrogen; absent fungi limit nitrogen availability for life in the ecosystem.