Comparisons of ribosomal RNA among many different modern species indicate that .a. there are two very divergent groups of prokaryotes;b. the Protista represents a conglomeration of very unrelated forms;c. fungi are more closely related to animals than to plants;d. A and B are correct;e. A, B, and C are correct

Progression through the cell cycle is regulated by oscillations in theconcentration of which type of molecule?a. p53, Rb, and other tumor suppressorsb. receptor tyrosine kinasesc. cyclinsd. cyclin-dependent kinases

The hyphae of arbuscular mycorrhizal fungi (AMF) form bushy structures after making contact with the plasma membrane of a root cell. What is the function of these structures?a. They anchor the fungus inside the root, so the association is more permanent.b. They increase the surface area available for the transfer of nutrients.c. They produce toxins that protect the plant cells against herbivores.d. They break down cellulose and lignin in the plant cell wall.

The most important adaptive advantage associated with the filamentous nature of fungal mycelia isa. the ability to form haustoria and parasitize other organisms.b. the potential to inhabit almost all terrestrial habitats.c. the increased chance of contact between mating types.d. an extensive surface area well suited for invasive growth and absorptive nutrition.

What does it mean to say that a hypha is dikaryotic?a. Two nuclei fuse during sexual reproduction to form a zygote.b. Two independent nuclei, derived from different individuals, are present in each cell.c. The nucleus is diploid or polyploid—not haploid.d. It is extremely highly branched, which increases its surface area and thus absorptive capacity.

Identify at least two events in the cell cycle that must be completed successfully for daughter cells to share an identical complement of chromosomes.

The Greek root ecto means 'outer.' Why are ectomycorrhizal fungi, or EMF, aptly named?a. Their hyphae form tree-like branching structures inside plant cell walls.b. They are mutualistic.c. Their hyphae form dense mats that envelop roots but do not penetrate the cell walls.d. They transfer nitrogen from outside their plant hosts to the interior.

SCIENTIFIC INQUIRY • INTERPRET THE DATA The grass Dichanthelium lanuginosum lives in hot soils and houses fungi of the genus Curvularia as endophytes. Researchers tested the impact of Curvularia on the heat tolerance of this grass. They grew plants without (E−) and with (E+) Curvularia endophytes at different temperatures and measured plant mass and the number of new shoots the plants produced. Draw a bar graph for plant mass versus temperature and interpret it.

Explain why fungi that degrade dead plant materials are important to the global carbon cycle. Do you accept the text's statement that, without these fungi, 'Terrestrial environments would be radically different than they are today, and probably much less productive'? Why or why not?