1) What soil composition would be best for availability of nutrients, water, and root development?

1. A) equal amounts of sand, clay, and humus
2. B) higher proportion of humus; lower amounts of clay and sand
3. C) higher proportion of clay; lower amounts of humus and sand
4. D) higher proportion of sand; lower amount of humus and clay 1) What soil composition would be best for availability of nutrients, water, and root development?
   1. A) equal amounts of sand, clay, and humus
   2. B) higher proportion of humus; lower amounts of clay and sand
   3. C) higher proportion of clay; lower amounts of humus and sand
   4. D) higher proportion of sand; lower amount of humus and clay

b

2) The highest amount of oxygen will be found in soils containing large amounts of ________.

1. A) clay
2. B) sand
3. C) gravel
4. D) silt

c

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. The most likely cause of this die-off is ________.

1. A) competition for resources
2. B) a lack of oxygen for the roots
3. C) organic nutrient depletion
4. D) no room left for root growth

b

4) There are several properties that are characteristic of a soil in which typical plants would grow well. Of the following, which would be the least conducive to plant growth?

1. A) abundant humus
2. B) numerous soil organisms
3. C) compacted soil
4. D) high cation exchange capacity

c

5) Which of the following soil minerals is most likely leached away during a hard rain?

1. A) Na+
2. B) K+
3. C) Ca++
4. D) NO3-

d

6) Which of the following are problems associated with intensive irrigation?

1. I) mineral runoff
2. II) over fertilization

III) aquifer depletion

1. IV) soil salinization

1. A) only I and II
2. B) only I, III, and IV
3. C) only III and IV
4. D) I, II, III, and IV

b

7) A young farmer purchases some land in a relatively arid area and is interested in earning a reasonable profit for many years. Which of the following strategies would best allow the farmer to achieve such a goal?

1. A) establishing an extensive irrigation system
2. B) using plenty of the best fertilizers
3. C) finding a way to sell all parts of crop plants
4. D) selecting crops adapted to arid areas

d

8) The NPK percentages on a package of fertilizer refer to the ________.

1. A) percentages of manure collected from different types of animals
2. B) relative percentages of organic and inorganic nutrients in the fertilizer
3. C) percentages of three important mineral nutrients
4. D) proportions of three different nitrogen sources

c

9) Which of the following would inhibit the growth of most plants?

1. A) abundant humus
2. B) air spaces
3. C) good drainage
4. D) a pH above 10.0

d

10) The B horizon of soil has ________.

1. A) living organisms and decaying organic matter
2. B) a mixture of broken soil with a variety of texture
3. C) much less organic matter than the A horizon
4. D) partially broken-down rock

c

11) Roots acidify the soil solution by releasing ________ and pumping ________ into the soil.

1. A) CO2; K+
2. B) CO2; H+
3. C) CO2; Na+
4. D) N; Na+

b

12) Soil pH is an important factor that influences ________.

1. A) cation exchange
2. B) the chemical form of minerals
3. C) availability of minerals
4. D) cation exchange and the chemical form of minerals

d

13) Soil erosion could be controlled by ________.

1. A) planting rows of trees as windbreaks
2. B) no-till agriculture
3. C) terrace hillside crops
4. D) all of the above

d

14) Which of the following would be the most effective strategy to remove toxic heavy metals from a soil?

1. A) heavy irrigation to leach out the heavy metals
2. B) application of sulfur to lower the soil pH and precipitate the heavy metals
3. C) adding plant species that have the ability to take up and accumulate heavy metals
4. D) inoculating soil with mycorrhizae to avoid heavy-metal uptake

c

15) How would you expect the root system of a plant grown by hydroponics to compare to the root system of a plant grown in soil? The root system of a plant grown by hydroponics would be ________.

1. A) more developed
2. B) less developed
3. C) about the same
4. D) absent

b

16) Deficiency of calcium in plants causes ________.

1. A) wilting and poor growth
2. B) chlorosis between veins and wilting
3. C) crinkling of young leaves and death of terminal buds
4. D) reduced internode length and crinkled leaves

c

17) Which one of the following elements plays a critical role in the formation of chlorophyll?

1. A) magnesium
2. B) manganese
3. C) calcium
4. D) zinc

a

18) Which of the following experiments is the best way to determine if an element is essential for plant growth?

1. A) Measure the amount of the element stored in plant tissues.
2. B) Measure the amount of the element in the soil after plant growth.
3. C) Measure the weight of the plant and soil before and after plant growth.
4. D) Grow a plant using hydroponics with and without the element.

d

19) Which criteria allow biologists to divide chemicals into macronutrients and micronutrients?

1. A) molecular weight of the element or compound
2. B) the quantities of each required by plants
3. C) how they are used in metabolism
4. D) whether or not they are essential for plant growth

b

20) Which elements are most often the limiting nutrients for plant growth?

1. A) nitrogen, potassium, phosphorus
2. B) nitrogen, oxygen, hydrogen
3. C) carbon, sodium, chlorine
4. D) carbon, nitrogen, oxygen

a

21) Synthesis of which of the following compounds in a mature leaf would be least impacted by a temporary soil nitrogen deficiency?

1. A) DNA
2. B) RNA
3. C) amino acids
4. D) cellulose

d

22) A major function of magnesium in plants is to be ________.

1. A) required to regenerate phosphoenolpyruvate in C4and CAM plants
2. B) a component of DNA and RNA
3. C) a component of chlorophyll
4. D) active in amino acid formation

c

23) Micronutrients are needed in very small amounts because ________.

1. A) most of them are mobile in the plant
2. B) most serve mainly as cofactors of enzymes
3. C) they play only a minor role in the growth and health of the plant
4. D) only the most actively growing regions of the plants require micronutrients

b

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 yellowish (less green) compared with those of the plants grown in the humus-enriched soil. The best explanation for this difference is that ________.

c

25) Soil leaching can cause nutrient deficiencies in the soil. Which of the following are symptoms of nutrient deficiency in plants?

1. I) chlorosis
2. II) death of meristems

III) excess storage of chlorophyll

1. IV) small internodes

1. A) I, II, and III
2. B) II, III, and IV
3. C) I, II, and IV
4. D) I, II, III, and IV

c

26) If an African violet has chlorosis, which of the following elements might be a useful addition to the soil?

1. A) molybdenum
2. B) copper
3. C) iodine
4. D) magnesium

d

27) Which one of the following micronutrients plays a critical role as a component of chlorophyll?

1. A) nickel
2. B) iron
3. C) magnesium
4. D) molybdenum

c

28) Nitrogen-fixing bacteria and nitrifying bacteria convert atmospheric nitrogen into different compounds of nitrogen such as: (a) ammonium ion, (b) ammonia, (c) nitrate ion, and (d) nitrite ion. Which of the following is the correct sequence of formation of the nitrogen compounds?

1. A) a, b, c, and d
2. B) b, a, d, and c
3. C) b, a, c, and d
4. D) a, b, d, and c

b

29) Which of the following plants is classified as an epiphyte?

1. A) Venus flytrap
2. B) pitcher plant
3. C) staghorn fern
4. D) mistletoe

c

30) Nitrogen fixation is a process that ________.

1. A) recycles nitrogen compounds from dead and decaying materials
2. B) converts ammonia to ammonium
3. C) releases nitrate from the rock substrate
4. D) converts nitrogen gas into ammonia

d

31) Why is nitrogen fixation an essential process?

1. A) Nitrogen fixation can only be done by certain prokaryotes.
2. B) Fixed nitrogen is often the limiting factor in plant growth.
3. C) Nitrogen fixation is very expensive in terms of metabolic energy.
4. D) Nitrogen fixers are sometimes symbiotic with legumes.

b

32) You are weeding your garden when you accidentally expose some roots of your pea plants. You notice swellings (root nodules) on the roots, and there is a reddish tinge to the ones you accidentally damaged. Most likely your pea plants ________.

1. A) suffer from a mineral deficiency
2. B) are infected with a parasite
3. C) are benefiting from a mutualistic bacterium
4. D) are developing offshoots from the root

c

33) The specific relationship between a legume and its mutualistic Rhizobium strain probably depends on ________.

1. A) each legume having a chemical dialogue with a fungus
2. B) each Rhizobium strain having a form of nitrogenase that works only in the appropriate legume host
3. C) each legume being found where the soil has only the Rhizobium specific to that legume
4. D) specific recognition between the chemical signals and signal receptors of the Rhizobium strain and legume species

d

34) Rhizobia, actinomycetes, and cyanobacteria all share the common feature that they can ________.

1. A) increase water uptake in plants
2. B) kill parasites in the soil
3. C) exist in extreme environments
4. D) fix atmospheric nitrogen

d

35) The earliest vascular plants on land had underground stems (rhizomes), but no roots. Water and mineral nutrients were most likely obtained by ________.

1. A) diffusion through stomata
2. B) absorption by mycorrhizae
3. C) osmosis through the root hairs
4. D) diffusion across the cuticle of the rhizome

b

36) What major benefits do plants and mycorrhizal fungi receive from their symbiotic relationship?

1. A) Plants receive enzymes, and fungi receive nitrogen and phosphorus.
2. B) Plants receive increased root surface area, and fungi receive digestive enzymes.
3. C) Fungi receive photosynthetic products in exchange for living in plant root nodules.
4. D) Plants receive nitrogen and phosphorus, and fungi receive photosynthetic products.

d

37) Hyphae form a covering over roots. These hyphae create a large surface area that helps to do which of the following?

1. A) aid in absorbing minerals and ions
2. B) maintain cell shape
3. C) increase cellular respiration
4. D) anchor a plant

a

38) A plant developed a mineral deficiency after being treated with a fungicide. What is the most probable cause of the deficiency?

1. A) Mineral receptor proteins in the plant membrane were not functioning.
2. B) Mycorrhizal fungi were killed.
3. C) Active transport of minerals was inhibited.
4. D) Proton pumps reversed the membrane potential.

b

39) We would expect the greatest difference in plant health between two groups of plants of the same species, one group with mycorrhizae and one group without mycorrhizae, in an environment ________.

1. A) where nitrogen-fixing bacteria are abundant
2. B) that has soil with poor drainage
3. C) in which the soil is relatively deficient in mineral nutrients
4. D) that is near a body of water, such as a pond or river

c

40) Which of the following is a primary difference between ectomycorrhizae and endomycorrhizae?

1. A) Endomycorrhizae have thicker, shorter hyphae than ectomycorrhizae.
2. B) Ectomycorrhizae do not penetrate root cells, whereas endomycorrhizae grow into invaginations of the root cell membranes.
3. C) Endomycorrhizae are more common than ectomycorrhizae.
4. D) There are no significant differences between ectomycorrhizae and endomycorrhizae.

Answer: B

b

41) Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of ________.

1. A) energy
2. B) carbohydrates
3. C) lipids and steroids
4. D) nitrogen and other minerals

d

42) Epiphytes are ________.

1. A) aerial vines common in tropical regions
2. B) plants that live in poor soil and digest insects to obtain nitrogen
3. C) plants that grow on other plants but do not obtain nutrients from their hosts
4. D) plants that have a symbiotic relationship with fungi

c

43) While hiking in a forest, you notice an unusual plant growing on the branches of a tree. What will help you to determine if this plant is epiphytic or parasitic?

1. A) If the plant is green, it is epiphytic; if not, then it is parasitic.
2. B) The root of an epiphytic plant will be in the soil, but a parasitic plant will grow from the trunk of a tree.
3. C) The roots of a parasitic plant will penetrate under the bark into the tree xylem, and the roots of epiphytic plant will not.
4. D) The epiphytic plant will have large water collecting leaves, and the parasitic plant will not.

c