1
Campbell Essential Biology, 6e (Simon/Dickey/Hogan/Reece)
Chapter 29 The Working Plant
Chapter 29 Learning Outcomes
29 Biology and Society: Planting Hope in the Wake of Disaster
29.1. Explain how phytoremediation is helping to address the damage caused by the 2011
earthquake disaster that struck Japan.
29.1 How Plants Acquire and Transport Nutrients
29.2. Describe where and how a plant obtains all the materials necessary to construct all the
organic materials it needs, including the adaptations used to obtain them.
29.3. Distinguish between micronutrients and macronutrients, noting examples of each.
29.4. Describe what constitutes organic farming, and list advantages of this type of farming.
29.5. Explain the cohesion-tension hypothesis responsible for the ascent of sap in xylem, and
the plant structures involved.
29.6. Explain how, when, and where phloem conducts sap.
29.2 Plant Hormones
29.7. Describe the general roles and properties of plant hormones, the specific roles of the five
major types, and how they are studied and used by humans to manipulate plants.
29.3 Response to Stimuli
29.8. Define phototropism, gravitropism, and thigmotropism and explain their significance in
plants.
29.9. Distinguish between short-night plants and long-night plants.
29 Evolution Connection: Plants, Bugs, and People
29.10. Explain how interacting organisms affect each other’s fitness.
Global Learning Outcomes
1. Demonstrate an understanding of the principles of scientific inquiry.
2. Demonstrate the ability to think critically and employ critical-thinking skills.
3. Read and interpret models, graphs, and data.
4. Demonstrate the quantitative skills needed to succeed in biology.
5. Demonstrate an understanding of the impact of science on society.
6. Evaluate the credibility of scientific information from various sources.
7. Demonstrate the ability to make connections between concepts across biology.
8. Communicate effectively in writing.
9. Apply the scientific method to interpret information and draw conclusions.
29.1 Multiple Choice Questions
1) In phytoremediation, plants are used to remove ________ and ________ from the soil.
A) carbon… heavy metals
B) radioactive isotopes… heavy metals
C) nitrogen… phosphorus
D) water… sulfur
2) Which of the following BEST describes the essential difference between plant and animal
nutrition?
A) Plants use inorganic substances and energy from the sun to produce their own food.
B) Plants use organic substances to produce their own food.
C) Plants absorb food through their roots.
D) Plant and animal nutrition are essentially the same.
3) For a plant, carbon and nitrogen are ________.
A) macronutrients
B) micronutrients
C) minerals
D) compost
4) Which of the following describes a chemical element that a plant must obtain from its
environment in order to complete its life cycle?
A) macronutrient
B) micronutrient
C) essential element
D) mineral
5) Which one of the following is a plant micronutrient?
A) iron
B) oxygen
C) sulfur
D) phosphorus
6) The three most important nutrients contained in fertilizers are ________.
A) nitrogen, iron, and phosphorus
B) zinc, sulfur, and phosphorus
C) nitrogen, phosphorus, and potassium
D) zinc, iron, and potassium
7) Which of the following best describes substances that enter a plant through the root system?
A) They are dissolved in water.
B) They are obtained from the air.
C) They are organic molecules.
D) They are brought in through stomata.
8) Which of the following supplies water and minerals to a typical plant?
A) the air
B) bacteria
C) sunlight
D) the soil
9) For plants, mycorrhizae are______.
A) parasitic
B) mutualistic
C) an adaptation for photosynthesis
D) agricultural pests
10) What does a plant gain from a mycorrhizal relationship?
A) It allows roots to absorb water and solutes more rapidly.
B) It increases the surface area for photosynthesis.
C) It helps to break down complex molecules in the soil to release micronutrients.
D) It helps to break down decaying organic matter into essential plant nutrients.
11) Which of the following convert atmospheric nitrogen to ammonium?
A) nitrifying bacteria
B) nitrogen-fixing bacteria
C) mycorrhizae
D) ammonifying bacteria
12) Which of the following convert soil ammonium to nitrate?
A) nitrifying bacteria
B) ammonifying bacteria
C) mycorrhizae
D) nitrogen-fixing bacteria
13) Which of the following best describes the role of plant root nodules in plants such as peas
and beans?
A) They house nitrogen-fixing bacteria.
B) They help absorb nutrients from the soil.
C) They house mycorrhizae.
D) They store nutrients.
14) Most plants rely on bacteria to supply them with a usable form of which of the following
substances?
A) nitrogen
B) carbon dioxide
C) water
D) amino acids
15) Which of the following best describes the conversion that occurs during nitrogen fixation?
A) ammonium to nitrate
B) nitrate to ammonium
C) nitrogen to ammonium
D) nitrogen to ammonium or nitrate
16) Which of the following best describes transpiration?
A) the loss of oxygen from a plant
B) evaporation from a plant’s roots
C) the bulk flow movement of water in a plant
D) the loss of water from plant leaves through evaporation
17) Which of the following mechanisms best explains how xylem sap moves up against the
downward pull of gravity?
A) cohesion-tension hypothesis
B) gravitropism
C) phototropism
D) expenditure of ATP
18) Which of the following weather conditions would cause transpiration to be most rapid?
A) hot, humid weather
B) cold, humid weather
C) hot, dry weather
D) windy, wet weather
19) Which of the following best describes the opening and closing of the stomata in most plants?
A) They are open during the day and closed at night.
B) They are open at night and closed during the day.
C) They are open almost all of the time.
D) They are closed except for brief periods of time during the day.
20) Which of the following best describes the mechanism that causes stomata to open?
A) Water accumulates below the opening and eventually causes the stoma to open.
B) A large bubble of oxygen accumulates below the stoma and eventually causes it to open.
C) Two guard cells flanking each stoma control its opening by changing shape.
D) The internal pressure of xylem sap expands the leaf, stretching the stoma open.
21) Transpiration pulls water up a plant because of two mechanisms: ________ describes water
molecules sticking together and ________ describes water molecules sticking to the walls of the
xylem.
A) cohesion… adhesion
B) adhesion… cohesion
C) adhesion… gravity
D) gravity… cohesion
22) Which of the following explains how phloem sap moves within a plant?
A) cohesion-tension mechanism
B) gravity pulls the phloem sap down
C) pressure-flow mechanism
D) transpiration
23) A location in a plant where sugar is being received for storage or consumption is ________.
A) a sugar sink
B) a sugar source
C) phloem sap
D) phloem tube
24) A farmer decides she wants to grow certified organic corn and sets out to meet all USDA
standards to do so. Her crop grows well for the first 3 years; however, she notices during the 4th
and 5th years that plants are getting smaller and producing much less corn. She has not altered
farming practices and begins to wonder what is happening. She remembers someone mentioning
planting peanuts every 3rd year in place of a corn crop, which leads to much healthier corn. Why
would a farmer want to change to a different crop, especially something like peanuts?
A) Planting a legume like peanuts increases water retention in the soil, allowing the following
year’s corn crop to thrive.
B) Crop rotation with a legume like peanuts will increase nitrogen in the soil, reducing the need
for chemical fertilizer.
C) Planting a legume like peanuts increases the available carbon in the soil.
D) Changing from corn to peanuts, a legume, allows the soil to “rest” for a year.
25) In a strawberry plant in the summer, the leaves are ________ and the strawberry fruits are
________.
A) sugar sources… sugar sources
B) sugar sources… sugar sinks
C) sugar sinks… sugar sources
D) sugar sinks… sugar sinks
26) Early in the spring, cherry trees produce flowers, even before their leaves develop, by using
sugars that were stored in their roots the previous year. While cherry flowers are developing, we
would expect the phloem pressure near flowers to be ________, and ________ near root storage
cells.
A) high… high
B) high… low
C) low… low
D) low… high
27) Trace the flow of a water molecule that is used during photosynthesis.
A) stoma → xylem → root hair → mycorrhiza
B) soil → root hair → xylem → stoma → atmosphere
C) soil → root hair → xylem → leaf cell
D) soil → xylem → leaf cell → atmosphere
28) Which of the following statements is TRUE?
A) A given hormone has the same effect on all parts of a plant.
B) A single hormone may have different effects depending on concentration and presence of
other hormones.
C) Plants and animals use hormones in very different ways.
D) Large amounts of hormones are required to affect plant growth and development.
29) Which of the following plant hormones affect(s) development in the plant body?
I) auxin
II) cytokinin
III) gibberellin
A) I
B) I and II
C) III
D) I, II, and III
30) Which of the following hormones promotes cell elongation in stems?
A) auxin
B) cytokinin
C) ethylene
D) gibberellin
31) Which of the following best describes the condition of a twig if the auxin produced by its
apical meristem is conveyed equally down all sides?
A) It will elongate.
B) It will branch near its tip.
C) It will produce a flower.
D) It will bend to one side.
32) Which of the following hormones promotes fruit ripening and dropping of leaves?
A) auxin
B) ethylene
C) gibberellin
D) abscisic acid
33) Which of the following hormones promotes cell division?
A) auxin
B) cytokinin
C) gibberellin
D) abscisic acid
34) Which of the following hormones promotes seed germination?
A) auxin
B) ethylene
C) gibberellin
D) abscisic acid
35) Which of the following hormones promotes seed dormancy?
A) cytokinin
B) ethylene
C) gibberellin
D) abscisic acid
36) Which of the following is exemplified by a pea tendril contacting a string or wire and coiling
around it for support?
A) gravitropism
B) photoperiod
C) thigmotropism
D) phototropism
37) Experimental plants that were sent up in space shuttle missions did not exhibit all of their
normal tropisms. Which of the following responses would you most expect to be lacking from
these plants?
A) gravitropism
B) photoperiod
C) thigmotropism
D) phototropism
38) Which of the following best describes night-neutral plants?
A) The plants flower at night.
B) Plants tend to flower when nights become longer.
C) Plants tend to flower when nights become shorter.
D) The flowering in these plants is not affected by photoperiod.