BIO 1108 EXAM 2 (HERRICK) PRACTICE QUESTIONS COMPLETE WITH ANSWERS AND RATIONALES

BIO 1108 EXAM 2 (HERRICK) PRACTICE QUESTIONS COMPLETE WITH ANSWERS AND RATIONALES Question 1 A researcher discovers a new species of fungi that form hyphae but not septa. This fungus also lacks multicellular fruiting bodies and does not appear to form either endomycorrhizae or ectomycorrhizae with plants. How should this fungus be classified? A) Ascomycetes B) Basidiomycetes C) Zygomycetes D) Glomeromycetes Answer: C) Zygomycetes Rationale: Zygomycetes are characterized by hyphae that lack septa (coenocytic hyphae), do not typically form complex multicellular fruiting bodies, and do not form mycorrhizal associations with plants. Ascomycetes and Basidiomycetes have septate hyphae, while Glomeromycetes form endomycorrhizae. ________________________________________ Question 2 A researcher is looking at different Petri dishes containing the yeast C. albicans. In the first dish she evaluates, she notices that the yeast do not form hyphae. Is this a mutant strain of yeast? A) Yes, because all yeasts can form hyphae under appropriate conditions B) No, as yeasts do not normally form hyphae C) Yes, because C. albicans always forms hyphae D) No, because hyphae formation requires bacterial co-culture Answer: B) No, as yeasts do not normally form hyphae Rationale: Yeasts are unicellular fungi that typically reproduce by budding and do not normally form hyphae. C. albicans can form hyphae under certain conditions, but the absence of hyphae does not indicate a mutant strain. ________________________________________ Question 3 Abscisic acid is a hormone produced by root cap cells as soils dry. What is its primary function? A) Stimulates flowering and fruit development B) Promotes cell elongation and root growth toward water C) Stimulates root elongation and triggers stomata to close, reducing demand for water D) Inhibits seed germination and promotes leaf abscission Answer: C) Stimulates root elongation and triggers stomata to close, reducing demand for water Rationale: ABA is produced in root cap cells in response to soil drying. It stimulates root elongation to reach deeper water sources and causes stomatal closure to reduce transpiration and water loss, effectively reducing the plant's demand for water. ________________________________________ Question 4 What adaptation in grasses allows them to recover after grazing? A) Deep taproots that store carbohydrates B) Stems are short with apical meristems close to the ground and leaves that are tightly imbricated and continue to grow from the base C) Production of toxic alkaloids that deter herbivores D) Rapid seed production before grazing occurs Answer: B) Stems are short with apical meristems close to the ground and leaves that are tightly imbricated and continue to grow from the base Rationale: Grasses have evolved adaptations to grazing including short stems that keep apical meristems near the ground where they are less likely to be removed, tightly overlapping leaves that protect growing points, and basal meristems that allow continued growth after the upper portions are consumed. ________________________________________ Question 5 Alkaloids are chemical defenses that: A) Disrupt cell wall synthesis in herbivores B) Are nitrogen-bearing compounds that damage the nervous system of animals C) Inhibit digestive enzymes in herbivorous insects D) Attract predators that consume herbivores Answer: B) Are nitrogen-bearing compounds that damage the nervous system of animals Rationale: Alkaloids are nitrogen-containing compounds that act as chemical defenses by affecting the nervous systems of animals that consume them. Examples include atropine, codeine, morphine, quinine, and ephedrine. ________________________________________ Question 6 What makes alkaloids a costly defense for plants? A) They require large amounts of carbon to synthesize B) Their nitrogen richness prevents plants from building proteins for photosynthesis C) They require specialized transport tissues D) They attract more herbivores than they deter Answer: B) Their nitrogen richness prevents plants from building proteins for photosynthesis Rationale: Alkaloids contain nitrogen, which is a limiting nutrient for plants. The investment of nitrogen into alkaloid production represents a cost because that nitrogen could otherwise be used for proteins needed for photosynthesis and growth. ________________________________________ Question 7 The alternation of generations in plants involves: