Deck 36: Plant Nutrition

Question 1

The five component elements in most proteins are carbon,

A) oxygen, sulfur, phosphorus, and potassium.
B) hydrogen, oxygen, nitrogen, and phosphorus.
C) hydrogen, oxygen, nitrogen, and sulfur.
D) hydrogen, nitrogen, sulfur, and potassium.
E) hydrogen, oxygen, phosphorus, and potassium.

Answer 1

C

Question 2

Nitrification is

A) performed only by plants.
B) the reduction of ammonium ions to nitrate ions.
C) the reduction of nitrate ions to nitrogen gas.
D) catalyzed by the enzyme nitrogenase.
E) performed by certain bacteria in the soil.

Answer 2

E

Question 3

Which of the following is an early step in the formation of both arbuscules and root nodules?

A) Invasion of a plant root by a fungus
B) Invasion of a plant root by a bacterium
C) Strigolactones produced by the root are recognized by the microbe
D) Root cells are invaded but there is no direct contact between plant and microbe cell contents
E) Root cells are invaded and there is direct contact between plant and microbe cell contents

Answer 3

D

Question 4

Hydrogen in hydrocarbons enters living systems from

A) the atmosphere.
B) oil and coal.
C) water.
D) H₂S.
E) All of the above

Question 5

Which of the following is a micronutrient in plants?

A) Potassium
B) Sulfur
C) Calcium
D) Iron
E) Magnesium

Question 6

Which four elements are found in highest concentration in plants?

A) Phosphorus, calcium, hydrogen, carbon
B) Magnesium, phosphorus, calcium, potassium
C) Magnesium, iron, phosphorus, potassium
D) Carbon, hydrogen, oxygen, nitrogen
E) Carbon, hydrogen, oxygen, potassium

Question 7

Nitrogen fixation is

A) performed only by plants.
B) the oxidation of nitrogen gas.
C) catalyzed by the enzyme nitrogenase.
D) a single-step chemical reaction.
E) possible because N₂ is a highly reactive substance.

Question 8

_______ are available to the plant in unlimited supply _______.

A) Water and nitrogen; because there is plenty of soil around the plant
B) Sulfur and magnesium; because the plant needs relatively small amounts from the soil
C) Phosphorus and iron; because they readily dissolve in soil water
D) Calcium and chlorine; because they are easily absorbed by the roots
E) Hydrogen and oxygen; as long as sufficient water is available

Question 9

Which of the following is a parasite?

A) Venus flytrap
B) Pitcher plant
C) Sundew
D) Dodder
E) Tobacco

Question 10

A photoautotroph acquires its carbon from

A) the soil.
B) the air.
C) water.
D) the sun.
E) carbon-fixing prokaryotes.

Question 11

Which of the following is not true for arbuscules?

A) They are an ancient association between plants and fungi.
B) They expand the effective root area of plants and allow more efficient water uptake.
C) They are a significant source of fixed nitrogen for plants.
D) They are a significant source of phosphorous for plants.
E) Most land plants have them.

Question 12

Macronutrients

A) are so called because they are more essential than micronutrients.
B) include manganese, boron, and zinc, among others.
C) function as catalysts.
D) are required in concentrations of at least 1 gram per kilogram of plant dry matter.
E) are obtained by the process of photosynthesis.

Question 13

Most plants continuously obtain new sources of mineral nutrients by

A) breaking down organic matter.
B) growing longer roots.
C) shading the plants below them.
D) evolving more elaborate photosystems.
E) absorbing minerals through leaves.

Question 14

All carnivorous plants

A) are parasites.
B) depend on animals as a source of carbon.
C) are incapable of photosynthesis.
D) depend on animals as their sole source of phosphorus.
E) obtain supplemental nitrogen from animals.

Question 15

Fertilizers

A) are often characterized by their N-P-O percentages.
B) are not required if crops are removed frequently enough.
C) restore needed mineral nutrients to the soil.
D) are needed to provide carbon, hydrogen, and oxygen to plants.
E) are needed to destroy soil pests.

Question 16

In a typical soil,

A) the topsoil tends to lose mineral nutrients by leaching.
B) there are four or more horizons.
C) the C horizon consists primarily of loam.
D) the dead and decaying organic matter gathers in the B horizon.
E) more clay means more air space and thus more oxygen for roots.

Question 17

Plants acquire minerals from the soil

A) by recycling them.
B) by growing.
C) from rainwater.
D) from soil microbes.
E) All of the above

Question 18

Which of the following is not an essential mineral element for plants?

A) Potassium
B) Magnesium
C) Calcium
D) Lead
E) Phosphorus

Question 19

One of the defining characteristics of an essential element is that

A) it is necessary only for early growth of the seedling.
B) it can be replaced by another element.
C) the plant cannot survive without it.
D) may function by relieving the toxicity of another element.
E) is found in relatively high concentrations in the environment.

Question 20

Plants do not obtain which of the following elements from the soil?

A) Carbon
B) Nitrogen
C) Potassium
D) Sulfur
E) Zinc

Question 21

In many crops, nitrogen deficiencies cause _______ leaves to become _______.

A) old; yellow
B) young; yellow
C) old; orange
D) young; orange
E) old; brown-spotted

Question 22

Use the following to answer questions:
Match the mineral nutrient in the list below with each description that follows. Each item may be used once, more than once, or not at all.
a. Magnesium
b. Nitrogen
c. Phosphorus
d. Potassium
e. Iron
This mineral is necessary for water and ion balance.

Question 23

Clay in soil

A) provides a reservoir of cation nutrients.
B) holds moisture.
C) binds mineral ions.
D) Both a and b
E) All of the above

Question 24

Which mineral is deficient in a plant whose growth is stunted and whose oldest leaves turn yellow and die prematurely?

A) Calcium
B) Iron
C) Magnesium
D) Nitrogen
E) Phosphorus

Question 25

Iron deficiencies cause _______ leaves to become _______.

A) old; yellow
B) young; yellow
C) old; orange
D) young; orange
E) old; brown-spotted

Question 26

Use the following to answer questions:
Match the mineral nutrient in the list below with each description that follows. Each item may be used once, more than once, or not at all.
a. Magnesium
b. Nitrogen
c. Phosphorus
d. Potassium
e. Iron
This micronutrient is necessary for chlorophyll synthesis.

Question 27

The process of ion exchange is the means by which

A) carbonic acid is added to soils.
B) positive ion nutrients are replaced by H⁺.
C) negative ion nutrients are incorporated into soils.
D) positive ions are replaced by negative ions.
E) neutral atoms become ions in soils.

Question 28

Which of the following is not a consequence of adding lime to acidic soil?

A) Raised soil pH
B) Increased nutrient availability to plants
C) Addition of calcium (Ca²⁺) to the soil
D) Release of hydrogen ions (H⁺) by clay particles
E) Increase in the soil's ability to retain water

Question 29

Use the following to answer questions:
Match the mineral nutrient in the list below with each description that follows. Each item may be used once, more than once, or not at all.
a. Magnesium
b. Nitrogen
c. Phosphorus
d. Potassium
e. Iron
When bonded to oxygen atoms, this mineral is important in many energy-storing and energy-releasing pathways where ATP is necessary.

Question 30

The best topsoils are composed of

A) clay.
B) sand.
C) organic matter.
D) Both a and b
E) All of the above

Question 31

The ionization of carbonic acid

A) triggers the release of mineral ions from clay.
B) lowers the pH of soil.
C) reduces the leaching of phosphates and nitrates from soil.
D) causes laterization of the A horizon of soil.
E) increases the amount of soil carbon available to plants.

Question 32

The advantage of adding organic fertilizers (as opposed to inorganic fertilizers) to soils is that organic fertilizers

A) improve the structure of soil.
B) are available in specific nutrient formulas for specific problems.
C) allow for a more rapid increase in nutrients.
D) leach the soil.
E) add clay particles to the soil.

Question 33

Use the following to answer questions:
Match the mineral nutrient in the list below with each description that follows. Each item may be used once, more than once, or not at all.
a. Magnesium
b. Nitrogen
c. Phosphorus
d. Potassium
e. Iron
This mineral is a constituent of both proteins and nucleic acids.

Question 34

Soil scientists recognize _______ major horizons: _______.

A) two; A and B
B) four; top, top middle, middle, and lower
C) seven; 1, 2, 3, 4, 5, 6, and 7
D) two; upper and lower
E) three; A, B, and C

Question 35

Which three elements are most commonly added to agricultural soils in fertilizers?

A) Nitrogen, phosphorus, iron
B) Nitrogen, potassium, iron
C) Potassium, sulfur, iron
D) Nitrogen, potassium, phosphorus
E) Nitrogen, sulfur, iron

Question 36

If a new essential nutrient were discovered, it would be a

A) macronutrient.
B) micronutrient.
C) rare gas.
D) small organism.
E) None of the above

Question 37

In almost all plants, roots get oxygen from

A) air spaces in the soil.
B) water in soil.
C) the leaves, by way of the phloem.
D) the leaves, which get oxygen from the air.
E) All of the above

Question 38

The maximum diameter of a clay particle is _______ $\mu$ m.

A) 2,000,000
B) 2,000
C) 2
D) 0.002
E) 0.000002

Question 39

Chemical weathering, an important part of soil formation, includes the

A) splitting of clays.
B) effects of freezing and thawing.
C) hydrolysis of rock.
D) crushing of rock.
E) drying of soils.

Question 40

Most earthworms can be found in

A) topsoil.
B) subsoil.
C) bedrock.
D) Both a and b
E) Both b and c

Question 41

The process of nitrogen fixation is the

A) uptake of atmospheric nitrogen by plants.
B) conversion of atmospheric nitrogen into ammonia.
C) production of nitrogen-bearing compounds in plants.
D) release of nitrogen into the atmosphere.
E) release of ammonia into the atmosphere.

Question 42

Plants in nature

A) usually have unlimited nitrogen supplies.
B) usually have limited nitrogen supplies.
C) usually can fix nitrogen from the air.
D) do not display symptoms when nitrogen is deficient.
E) have yellow older leaves when nitrogen is overabundant.

Question 43

Nitrogenase enzymes are inhibited by _______ molecules.

A) hydrogen
B) oxygen
C) water
D) CO₂
E) calcium carbonate

Question 44

Compared to organic nitrogen sources, commercial nitrogen-containing fertilizer is an imperfect solution to the worldwide problem of soil degradation because

A) its production requires a great deal of energy.
B) it pollutes lakes and streams.
C) soil applications do not always benefit the plants.
D) the cost of shipping offsets the benefits to agricultural production.
E) it can never be as good as organic sources.

Question 45

An advantage to using inorganic fertilizers (as opposed to organic fertilizers) is that

A) they improve the physical properties of the soil.
B) they can be taken up almost instantaneously.
C) their quality is better than that of organic fertilizers.
D) they contain minerals in their proper ionic form.
E) None of the above

Question 46

Which of the following statements about the chemical process of nitrogen fixation in cells is true?

A) All three bonds between nitrogen atoms are broken simultaneously.
B) Hydrogen ions are added to N₂ in three successive pairs.
C) Very little energy in the form of ATP is required.
D) A different enzyme catalyzes each of the many reactions.
E) It is enhanced by high oxygen concentrations.

Question 47

In the legume-Rhizobium symbiosis, the _______ partner produces leghemoglobin to provide _______ to the _______ partner.

A) legume; oxygen; Rhizobium
B) Rhizobium; oxygen; legume
C) legume; nitrogen; Rhizobium
D) Rhizobium; nitrogen; legume
E) legume; sugars; Rhizobium

Question 48

The industrial production of nitrogen-containing fertilizer is currently limited by

A) its high energy expense.
B) the inability to insert nitrogenase genes into plants.
C) the lack of nitrogenase for the industrial process.
D) the limited supply of N₂ gas.
E) the need to exclude free oxygen in the process.

Question 49

Nitrogen fixers belong to which of the following groups?

A) Cyanobacteria
B) Bacteria and Archaea
C) Plantae
D) Archaea
E) Bacteria and Plantae

Question 50

Which of the following is not essential to the process of nitrogen fixation?

A) N₂ gas
B) O₂ gas
C) A strong reducing agent
D) A great deal of energy
E) The enzyme nitrogenase

Question 51

Nodules that are actively fixing nitrogen are pink, demonstrating the presence of

A) iron.
B) chlorophyll.
C) leghemoglobin.
D) anthocyanin.
E) alkaloids.

Question 52

The most common gas in the atmosphere is

A) CO₂.
B) nitrogen.
C) oxygen.
D) ozone.
E) water vapor.

Question 53

In nitrogen fixation, the nitrogenase enzyme binds a molecule of N₂ and a reducing agent transfers _______ hydrogen atoms before the product is released.

A) two
B) three
C) four
D) five
E) six

Question 54

Root nodules on plants of the legume family contain

A) cyanobacteria.
B) Nitrosococcus bacteria.
C) Rhizobium bacteria.
D) Pseudomonas bacteria.
E) Nitrobacter bacteria.

Question 55

Cyanobacteria are known to fix nitrogen in association with all of the following except

A) fungi in lichens.
B) ferns.
C) bryophytes.
D) cycads.
E) wheat.

Question 56

Most of the nitrogen on Earth exists in the form of

A) ammonia.
B) nitrate ions.
C) N₂ gas.
D) amino acids.
E) proteins.

Question 57

Which of the following plants does not have nitrogen-fixing root nodules containing Rhizobium?

A) Alfalfa
B) Beans
C) Clover
D) Peas
E) Rice

Question 58

How do nitrogen-fixing microbes first become symbiotic with their plants?

A) They are carried in the seed.
B) They are attracted by chemicals released by the root.
C) They move in via openings in the plant cell walls.
D) They move into the vascular system and multiply.
E) They enter root nodules previously produced by the plant.

Question 59

The form of nitrogen from the soil that most plants prefer is

A) found in amino acids.
B) ammonia.
C) N₂.
D) nitrate.
E) nitrite.

Question 60

Nitrogen fixers convert

A) ammonia to N₂.
B) N₂ to ammonia.
C) ammonia to nitrate.
D) nitrate to ammonia.
E) N₂ to nitrate.

Question 61

Decomposed plant litter produces a dark-colored organic material called _______.

Question 62

Some essential elements that occur as positive ions in soils may be traded with H⁺ ions in soil solutions by the process of _______.

Question 63

Plants acquire their essential mineral nutrients from water and the _______.

Question 64

Bacteria that function as denitrifiers

A) oxidize ammonium ions to nitrate.
B) oxidize nitrate to nitrite.
C) reduce N₂ to ammonia.
D) reduce nitrates to ammonia.
E) oxidize nitrate to N₂.

Question 65

The capture and digestion of insects allows carnivorous plants to

A) pollinate their flowers.
B) absorb nitrogen compounds.
C) disperse their fruits.
D) overcome insect parasitism.
E) neutralize acidic soils.

Question 66

The process that is the opposite of nitrogen fixation is

A) nitrification.
B) denitrification.
C) aerobic breakdown of amino acids.
D) release of ammonia.
E) nitrate reduction.

Question 67

Which of the following nitrogen compounds is used directly by plants to build proteins?

A) Ammonium
B) N₂
C) Nitrate
D) Nitrite
E) Nitrous oxide

Question 68

Because of leaching and crop production, soils may become depleted of nutrients and require the addition of _______.

Question 69

The minerals required by plants in concentrations of less than 100 milligrams per kilogram of their dry matter are called _______.

Question 70

One example of a nutrient in reduced form is the

A) carbon in CO₂.
B) hydrogen in water.
C) nitrogen in ammonia.
D) phosphorus in phosphate.
E) sulfur in sulfate.

Question 71

Soils can have as many as _______ horizons.

Question 72

Nutrients that are necessary for plant growth and reproduction, are not replaceable by another nutrient, and are required by the plant directly are called _______.

Question 73

The products of nitrogen-fixing organisms can be oxidized to form nitrites and nitrates by

A) all living organisms.
B) most living organisms that utilize oxygen.
C) many types of microorganisms.
D) a few specific genera of soil bacteria.
E) only the nitrogen-fixing bacteria.

Question 74

The three elements most commonly added to agricultural soils are _______, _______, and _______.

Question 75

A stunted dark green plant with purple veins is showing signs of _______ deficiency.

Question 76

Haustoria are structures of some

A) parasitic plants.
B) carnivorous plants.
C) nitrate-reducing plants.
D) denitrifying bacteria.
E) nitrogen-fixing bacteria.

Question 77

Although mistletoes are green, they are considered to be parasites because

A) they depend on other plants for water and minerals.
B) they cling to woody plants for physical support.
C) they capture and digest insects.
D) they have root nodules containing nitrogen-fixing Rhizobium.
E) their chlorophyll is not functional.

Question 78

The source from which plants derive their carbon is the _______.

Question 79

Plants use the essential element _______ as a messenger.

Question 80

Carnivorous plants use insects as a source of

A) calcium.
B) carbon.
C) energy.
D) hydrogen.
E) nitrogen.