front 1 1) What soil composition would be best for availability of nutrients, water, and air for root development? A) equal amounts of sand, clay, and silt B) higher proportion of silt; lower amounts of clay and sand C) higher proportion of clay; lower amounts of silt and sand D) higher proportion of sand; lower amount of silt and clay | back 1 A |
front 2 2) Soils containing large amounts of which of the following components will provide the least amount of oxygen to growing roots? A) clay B) sand C) humus D) silt | back 2 A |
front 3 3) A group of ten tomato plants are germinated and maintained in a large tray with no drainage. After several weeks they all begin to wilt and die despite repeated watering and fertilization. Which of the following is the most likely cause of the plant death? A) competition for resources B) a lack of oxygen for the roots C) organic nutrient depletion D) no room left for root growth | back 3 B |
front 4 4) Which of the following properties is least conducive to plant growth? A) abundant humus B) numerous soil organisms C) compacted soil D) high cation exchange capacity | back 4 C |
front 5 5) Which of the following soil minerals is most likely leached away by a hard rain? A) Na | back 5 B) K+ C) Ca2+ D) NO3- +D |
front 6 6) Which of the following is not a problem resulting from intensive irrigation? A) mineral runoff B) over fertilization C) aquifer depletion D) soil salinization | back 6 B |
front 7 7) A farmer purchases land in a relatively arid area and is interested in earning a reasonable profit for many decades. Which of the following strategies would best allow the farmer to achieve such a goal? A) establishing an extensive irrigation system B) using plenty of the best fertilizers C) finding a way to sell all parts of crop plants D) selecting crops adapted to arid areas | back 7 D |
front 8 8) What does the N-P-K ratio on a package of fertilizer indicate? A) percentages of manure collected from different types of animals B) relative percentages of organic and inorganic nutrients in the fertilizer C) percentages of three important mineral nutrients D) proportions of three different nitrogen sources | back 8 C |
front 9 9) Which of the following soil conditions would inhibit the growth of most plants? A) abundant humus mixed with loam B) air spaces in the topsoil C) poor drainage in the C horizon D) absence of an A horizon | back 9 D |
front 10 10) The B horizon of soil is characterized by which of the following? A) living organisms and decaying organic matter B) a mixture of broken soil with a variety of texture C) much less organic matter than the A horizon D) partially broken-down rock | back 10 C |
front 11 11) Which answer best describes how roots acidify the soil solution? A) Roots release CO₂ and pump K⁺ into the soil. B) Roots release CO₂ and pump H⁺ into the soil. C) Roots release NaCl and pump Na⁺ into the soil. D) Roots release NaCl and pump Cl⁻ into the soil. | back 11 B |
front 12 12) Soil pH is an important factor that influences which of the following? A) cation exchange B) the chemical form of minerals C) availability of organic matter D) cation exchange and the chemical form of minerals | back 12 D |
front 13 13) Which of the following techniques is not intended to reduce soil erosion? A) planting rows of trees as windbreaks B) no-till agriculture C) terrace hillside crops D) plowing over stubble immediately after harvest | back 13 D |
front 14 14) Which of the following is the least disruptive strategy for removing toxic heavy metals from a soil? A) heavy irrigation to leach out the heavy metals B) application of sulfur to lower the soil pH and precipitate the heavy metals C) adding plant species that have the ability to take up and accumulate heavy metals D) inoculating soil with mycorrhizae to avoid heavy-metal uptake | back 14 C |
front 15 15) During an experiment to identify essential nutrients, all but one class group observed the effects of micronutrient deficiencies on plant growth. Which of the following is the best explanation for the normal plant appearance in the one outlier group? A) The discrepant group did not pipette accurately. B) The discrepant group mislabeled their containers. C) The discrepant group used tap water instead of deionized (distilled) water. D) The discrepant group forgot to add micronutrient solution. | back 15 C |
front 16 16) Which answer best explains how nitrogen deficiency in plants causes chlorosis at the tips of older leaves? A) Nitrogen is a component of chlorophyll, but it is mobile and is re-located from older leaves to growing parts. B) Nitrogen is necessary to synthesize chlorophyll in mature areas of older leaves. C) Nitrogen is a component of all enzymes, so new growth will stop if nitrogen is deficient. D) Nitrogen regulates proton pumps that supply energy to growing tissue at the tips of older leaves. | back 16 A |
front 17 17) Which one of the following elements plays a critical role in the structure of chlorophyll? A) magnesium B) manganese C) calcium D) zinc | back 17 A |
front 18 18) Which of the following experiments is the best way to determine if an element is essential for plant growth? A) Measure the amount of the element stored in plant tissues. B) Measure the amount of the element in the soil before and after plant growth. C) Measure the weight of the plant and soil before and after plant growth. D) Grow a plant using hydroponics with and without the element. | back 18 D |
front 19 19) Which criteria allow biologists to classify chemicals into macronutrients and micronutrients? A) molecular weight of the element or compound B) the quantities of each required by plants C) how they are used in metabolism D) whether or not they are essential for plant growth | back 19 B |
front 20 20) Which elements are most often the limiting nutrients for plant growth? A) nitrogen, potassium, phosphorus B) nitrogen, oxygen, hydrogen C) carbon, sodium, chlorine D) carbon, nitrogen, oxygen | back 20 A |
front 21 21) Synthesis of which of the following compounds in a mature leaf would be least impacted by a temporary soil nitrogen deficiency? A) DNA B) RNA C) amino acids D) cellulose | back 21 D |
front 22 22) Which of the following is a major function of potassium in plants? A) regenerate ATP from ADP B) be a component of DNA and RNA C) be a component of chlorophyll D) control guard cell function | back 22 D |
front 23 23) Why are micronutrients needed in only very small amounts? A) most micronutrients are mobile in the plant B) most micronutrients serve mainly as cofactors of enzymes C) micronutrients play only a minor role in the growth and health of the plant D) only the most actively growing regions of the plants require micronutrients | back 23 B |
front 24 24) Two groups of tomatoes were grown under laboratory conditions, one with humus added to the soil, and one a control without humus. The leaves of the plants grown without humus were less green compared with those of the plants grown in the humus-enriched soil. Which of the following is the best explanation for this difference? A) the healthy plants used the food in the decomposing leaves of the humus for energy to make chlorophyll B) the humus made the soil more loosely packed, so water penetrated more easily to the roots C) the humus contained minerals such as magnesium and iron, needed for the synthesis of chlorophyll D) the heat released by the decomposing leaves of the humus caused more rapid growth and chlorophyll synthesis | back 24 C |
front 25 25) Soil leaching can cause nutrient deficiencies in the soil. Which of the following is not a symptom of nutrient deficiency in plants? A) chlorosis B) death of meristems C) excess storage of chlorophyll D) small internodes | back 25 C |
front 26 26) If garden tomatoes display chlorosis, which of the following fertilizers would likely reduce this symptom? A) 10-0-0 B) 0-10-0 C) 0-0-10 D) 0-0-0 | back 26 A |
front 27 27) Which one of the following nutrients plays a critical role as a component of proteins? A) potassium B) calcium C) magnesium D) sulfur | back 27 D |
front 28 28) Of the following terms, which best describes the ecological role of a Venus flytrap? A) parasite B) mutualist C) epiphyte D) predator | back 28 D |
front 29 29) Nitrogen-fixing bacteria and nitrifying bacteria convert atmospheric nitrogen into different compounds of nitrogen such as: I) ammonium ion II) ammonia III) nitrate ion IV) nitrite ion. Which of the following is the correct sequence of formation of the nitrogen compounds? A) I, II, III, and IV B) II, I, IV, and III C) II, I, III, and IV D) I, II, IV, and III | back 29 B |
front 30 30) Which of the following best describes the process of nitrogen fixation? A) recycles nitrogen compounds from dead and decaying materials B) converts ammonia to ammonium C) releases nitrate from the rock substrate D) converts nitrogen gas into ammonia | back 30 D |
front 31 31) How does nitrogen fixation lead to enhanced plant growth? A) Nitrogen fixation enables prokaryotes to supply the plant with proteins directly. B) Fixed nitrogen can be used by plants to produce protein. C) Nitrogen fixation directly by the plant is very expensive in terms of metabolic energy. D) Nitrogen fixation prevents herbivores from eating the plant. | back 31 B |
front 32 32) You are weeding your garden when you accidentally expose some roots of your pea plants, which are legumes like soybeans. You notice swellings (root nodules) on the roots, and there is a reddish tinge to the ones you accidentally damaged. These observations are evidence for which of the following? A) The peas suffer from a mineral deficiency. B) The peas are infected with a parasite. C) The peas are benefiting from a mutualistic bacterium. D) The peas are developing root buds to form branch roots. | back 32 C |
front 33 33) Which of the following best explains the specific relationship between a particular legume species and its mutualistic Rhizobium strain? A) Each legume has a chemical dialogue with the nearest fungus. B) Each Rhizobium strain contains a form of nitrogenase that works only in the appropriate legume host. C) A legume species occurs where the soil has only the Rhizobium strain specific to that legume. D) The chemical signals of a legume species match the signal receptors of a specific Rhizobium strain. | back 33 D |
front 34 34) Which of the following is a common feature shared by rhizobial bacteria, actinomycete bacteria, and cyanobacteria? A) They increase water uptake in plants. B) They kill parasites in the soil. C) Each exists only in extreme environments. D) Each fixes atmospheric nitrogen. | back 34 D |
front 35 35) The earliest vascular plants on land had underground stems (rhizomes), but no roots. Which of the following explains how the plants obtained water and mineral nutrients? A) diffusion through stomata B) absorption by mycorrhizae C) osmosis through the root hairs D) diffusion across the cuticle of the rhizome | back 35 B |
front 36 36) Which major benefits do plants and mycorrhizal fungi receive from their symbiotic relationship? A) Plants receive enzymes, and fungi receive nitrogen and phosphorus. B) Plants receive increased root surface area, and fungi receive digestive enzymes. C) Fungi receive photosynthetic products in exchange for living in plant root nodules. D) Plants receive water and phosphorus, and fungi receive photosynthetic products. | back 36 D |
front 37 37) The hyphae of ectomycorrhizae form a covering over roots. These hyphae create a large surface area that helps to do which of the following? A) aid in absorbing minerals and ions B) maintain cell shape C) increase cellular respiration D) anchor a plant | back 37 A |
front 38 38) Which of the following is the most probable cause of a mineral deficiency in a plant after being treated with a fungicide? A) Mineral receptor proteins in the plant membrane were not functioning. B) Mycorrhizal fungi were killed. C) Active transport of minerals was inhibited. D) Proton pumps reversed the membrane potential. | back 38 B |
front 39 39) In which of the following environments would we expect the greatest difference in plant health between two groups of plants of the same species, one group with mycorrhizae and the other group without mycorrhizae? A) where nitrogen-fixing bacteria are abundant B) soil with poor drainage C) soil deficient in mineral nutrients D) near a body of water, such as a pond or river | back 39 C |
front 40 40) Which of the following is a primary difference between ectomycorrhizae and endomycorrhizae? A) Endomycorrhizae have thicker, shorter hyphae than ectomycorrhizae. B) Ectomycorrhizae do not penetrate root cells, whereas endomycorrhizae grow into invaginations of the root cell membranes. C) Endomycorrhizae are more common than ectomycorrhizae. D) There are no significant differences between ectomycorrhizae and endomycorrhizae. | back 40 B |
front 41 41) Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used predominantly to supplement the plant's supply of which of the following? A) energy B) carbohydrates C) lipids and steroids D) nitrogen and other minerals | back 41 D |
front 42 42) Which of the following best describes epiphytes? A) aerial vines common in tropical regions B) plants that live in poor soil and digest insects to obtain nitrogen C) plants that grow on other plants but do not obtain nutrients from their hosts D) plants that have a symbiotic relationship with fungi | back 42 C |
front 43 43) While hiking in a forest, you notice an unusual plant growing on the branches of a tree. Which of the following criteria will best will help you to determine if this plant is epiphytic or parasitic? A) If the plant is green, it is epiphytic. B) The root of an epiphytic plant will be in the soil. C) The roots of a parasitic plant will penetrate through the bark into the xylem. D) The epiphytic plant will have large water collecting leaves. | back 43 C |
front 44 1) The inorganic nutrient most often lacking in crops is ________. A) carbon B) nitrogen C) phosphorus D) potassium | back 44 B |
front 45 2) Micronutrients are needed in very small amounts because ________. A) most of them are mobile in the plant B) most serve mainly as cofactors of enzymes C) most are supplied in large enough quantities in seeds D) they play only a minor role in the growth and health of the plant | back 45 B |
front 46 3) Mycorrhizae enhance plant nutrition mainly by ________. A) absorbing water and minerals through the fungal hyphae B) providing sugar to root cells, which have no chloroplasts C) converting atmospheric nitrogen to ammonia | back 46 A |
front 47 4) Epiphytes are ________. A) fungi that attack plants B) fungi that form mutualistic associations with roots C) nonphotosynthetic parasitic plants D) plants that grow on other plants | back 47 D |
front 48 5) A problem with intensive irrigation is ________. A) overfertilization B) aquifer depletion C) the long-term depletion of soil oxygen D) the clogging of waterways by vegetation debris | back 48 B |
front 49 6) A mineral deficiency is likely to affect older leaves more than younger leaves if ________. A) the mineral is a micronutrient B) the mineral is very mobile within the plant C) the mineral is required for chlorophyll synthesis D) the mineral is a macronutrient | back 49 B |
front 50 7) The greatest difference in health between two groups of plants of the same species, one group with mycorrhizae and one group without mycorrhizae, would be in an environment ________. A) where nitrogen-fixing bacteria are abundant B) that has soil with poor drainage C) that has hot summers and cold winters D) in which the soil is relatively deficient in mineral nutrients | back 50 D |
front 51 8) Two groups of tomatoes were grown under laboratory conditions, one with humus added to the soil and one a control without humus. The leaves of the plants grown without humus were yellowish (less green) compared with those of the plants grown in humus-enriched soil. The best explanation is that ________. A) the healthy plants used the food in the decomposing leaves of the humus for energy to make chlorophyll B) the humus made the soil more loosely packed, so water penetrated more easily to the roots C) the humus contained minerals such as magnesium and iron needed for the synthesis of chlorophyll D) the heat released by the decomposing leaves of the humus caused more rapid growth and chlorophyll synthesis | back 51 C |
front 52 9) The specific relationship between a legume and its mutualistic Rhizobium strain probably depends on ________. A) each legume having a chemical dialogue with a fungus B) each Rhizobium strain having a form of nitrogenase that works only in the appropriate legume host C) each legume being found where the soil has only the Rhizobium specific to that legume D) specific recognition between chemical signals and signal receptors of the Rhizobium strain and legume species | back 52 D |