Deck 25: Plant Nutrition and Transport

Question 1

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.

Answer 1

D

Question 2

Micronutrients are _______ in concentration than macronutrients by a factor of at least _______.

A) higher;100
B) lower;100
C) lower;10
D) higher;50
E) lower;50

Answer 2

C

Question 3

A botanist performs a series of experiments in which different possible sources of hydrogen to be used by plants are radioactively labeled.When photosynthetically derived compounds from the plants are later examined,their hydrogen will be found to have come from which source?

A) The atmosphere
B) Soil minerals
C) Water
D) Other plants
E) Fungi

Answer 3

C

Question 4

Soil scientists recognize _______ major soil 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 5

In almost all plants,roots get most of their oxygen from

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

Question 6

Researchers discover that a species of maple tree cannot survive and complete its life cycle without tiny amounts of cadmium.For this tree,cadmium is a(n)

A) macromolecule.
B) macronutrient.
C) essential element.
D) amino acid.
E) essential micronutrient.

Question 7

Plants,which are mostly autotrophs,acquire carbon from

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

Question 8

Which element is a plant micronutrient?

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

Question 9

A newly discovered species of earthworm is found to spend most of its time in the C horizon.This is unusual,since other species tend to stay in the

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

Question 10

Which mineral is a constituent of both proteins and nucleic acids?

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

Question 11

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 12

One of the defining characteristics of an essential element is that it

A) is necessary only for early growth of the seedling in plants.
B) can be replaced by another element.
C) is usually necessary for a plant's survival.
D) functions by relieving the toxicity of another element.
E) is found in relatively high concentrations in the environment.

Question 13

Which of the following represents the correct size ordering of these three mineral particles of the soil,from smallest to largest?

A) Clay $\rightarrow$ silt $\rightarrow$ sand
B) Sand $\rightarrow$ clay $\rightarrow$ humus
C) Sand $\rightarrow$ silt $\rightarrow$ clay
D) Humus $\rightarrow$ silt $\rightarrow$ sand
E) Silt $\rightarrow$ sand $\rightarrow$ loam

Question 14

Which mineral is most likely deficient in a tomato plant whose growth is stunted?

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

Question 15

Plants obtain all of the following elements from the soil except

A) carbon.
B) nitrogen.
C) potassium.
D) sulfur.
E) zinc.

Question 16

Nitrogen is typically present in plants in concentrations of 15 g/kg dry weight.Thus it is classified as a(n)

A) micronutrient.
B) macronutrient.
C) essential element.
D) nonessential element.
E) mineral nutrient.

Question 17

_______ 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 18

Plants acquire minerals

A) from the soil solution.
B) by growing toward them.
C) from rainwater.
D) from soil microbes.
E) by recycling them.

Question 19

Plants do not depend on soil for

A) O₂ for root respiration.
B) the services of other soil organisms,including bacteria,fungi,protists,and animals such as earthworms and arthropods.
C) CO₂.
D) anchorage for mechanical support of the shoot.
E) mineral nutrients and water.

Question 20

If a corn plant lacks the micronutrient _______,it will not be able to complete synthesis of its chlorophyll.

A) magnesium
B) sulfur
C) phosphorus
D) potassium
E) iron

Question 21

The mycorrhizal relationship allows a plant's roots to

A) increase the amount of soil than can be accessed for nutrients.
B) grow in nutrient-poor soils.
C) increase the amount of water that can be accessed.
D) avoid direct interaction with the soil.
E) None of the above

Question 22

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 23

The richest topsoils for agriculture are composed of

A) clay.
B) sand.
C) organic matter.
D) silt.
E) All of the above

Question 24

Which statement about mycorrhizal relationships is false?

A) Arbuscules are the sites of nutrient exchange in the mycorrhizal relationship.
B) Arbuscular mycorrhizae represent the most common mutual relationship between plant roots and fungi.
C) Plant roots send signals to soil-borne fungi and those fungi in turn send signals to the roots.
D) The cytoplasm of the plant and fungal cells do not come into contact.
E) Plant roots form mycorrhizal relationships to fend off infection by harmful fungi.

Question 25

If a soil has both a high clay content and is rich in nutrients,the roots of plants growing there will likely

A) benefit from the ability of clay to hold water and nutrients.
B) have difficulty accessing water but not nutrients.
C) be unable to benefit from available water and nutrients because of lack of air.
D) be deprived of water and the nutrients that bind tightly to clay particles.
E) take up water easily but experience nutrient shortages.

Question 26

The ionization of carbonic acid

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

Question 27

One 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 28

If you were going to try to get non-legumes to nodulate for the nutritional benefit of the plants,which part of the plants would you work on modifying?

A) Roots
B) Stems
C) Leaves
D) Flowers
E) Petioles

Question 29

The process of ion exchange is the means by which

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

Question 30

The nitrogen-fixing form of rhizobia that can be found inside the roots of a legume are known as

A) endospores.
B) cyanobacteria.
C) bacteroids.
D) heterocysts.
E) strigolactones.

Question 31

Ion exchange allows plant roots to

A) break down and dissolve minerals in the soil by acidifying the immediate soil environment.
B) use protons pumped from root cells to bind to nutrients.
C) counteract the leaching of nutrients.
D) release protons in return for positively charged nutrients that are bound to soil particles.
E) carry out respiration efficiently.

Question 32

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

A) water-based breakdown of rock.
B) effects of freezing and thawing.
C) leaching of nutrients.
D) crushing of rock.
E) drying of soils.

Question 33

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

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

Question 34

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 from soil.
E) add clay particles to the soil.

Question 35

Which statement about mycorrhizae is true?

A) They increase the functional surface area of a root system.
B) They involve an interaction between a bacterium and a plant.
C) They are very unusual in nature and are found only in specialized plant groups.
D) They spread via plant seeds.
E) They form structures that exclude oxygen.

Question 36

Which step occurs early 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) Recognition by the microbe of strigolactones produced by the root
D) Invasion of root cells,with no direct contact between plant and microbe cell contents
E) Invasion of root cells,with direct contact between plant and microbe cell contents

Question 37

Which of the following represents the correct order of soil horizons that you would encounter if you started digging in your garden?

A) Parent rock $\rightarrow$ subsoil $\rightarrow$ topsoil
B) Topsoil $\rightarrow$ subsoil $\rightarrow$ parent rock
C) Topsoil $\rightarrow$ parent rock $\rightarrow$ subsoil
D) Parent rock $\rightarrow$ topsoil $\rightarrow$ subsoil
E) Subsoil $\rightarrow$ parent rock $\rightarrow$ topsoil

Question 38

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

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

Question 39

Root nodules on plants of the legume family contain

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

Question 40

Which statement about arbuscules is false?

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

Question 41

One example of a reduced form of a nutrient is the _______ in _______.

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

Question 42

If you were working in the lab with nitrogenase,and the nitrogenase stopped catalyzing the reaction,you might need to eliminate or reduce the _______ in the experimental system to get it working again.

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

Question 43

Which is not essential to the process of biological nitrogen fixation in soybean (legume)nodules?

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

Question 44

Venus flytrap plants obtain various nutrients from their prey,but their greatest gain is used for protein synthesis.That nutrient is

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

Question 45

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

A) nitrogen.
B) chlorophyll.
C) leghemoglobin.
D) nitrogenase.
E) CO₂.

Question 46

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 47

The part of the root that is most important for building the bulk of a root nodule is the

A) epidermis.
B) cortex.
C) xylem.
D) phloem.
E) root hair.

Question 48

The capture and digestion of arthropods allows carnivorous plants to

A) pollinate their flowers.
B) overcome insect parasitism.
C) disperse their fruits.
D) absorb otherwise unavailable nutrients.
E) neutralize acidic soils.

Question 49

Photosynthetic plants that steal from other plants are known as _______,while those that cannot carry out photosynthesis are called _______.

A) parasites;holoparasites
B) hemiparasites;protoparasites
C) protoparasites;holoparasites
D) hemiparasites;holoparasites
E) hemiparasites;parasites

Question 50

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 51

The mycorrhizal relationship primarily increases the availability of _______ to plants.

A) iron
B) nitrogen
C) potassium
D) zinc
E) phosphorus

Question 52

What is the energy cost to plants for their associations with soil organisms such as mycorrhizae and nitrogen fixers?

A) A slowing of growth
B) Increased susceptibility to disease
C) Decreased reproductive success
D) A loss of over 50 percent of the products of photosynthesis
E) None of the above

Question 53

Although mistletoes are able to photosynthesize,they are considered to be hemiparasites because they

A) cling to woody plants for physical support.
B) depend on other plants for water and minerals.
C) capture and digest insects.
D) have root nodules containing nitrogen-fixing rhizobia.
E) have nonfunctioning chlorophyll.

Question 54

In the legume-rhizobia symbiosis,the _______ partner produces leghemoglobin to maintain _______ levels for the other partner.

A) legume;low oxygen
B) rhizobia;low oxygen
C) legume;high nitrogen
D) rhizobia;high nitrogen
E) legume;high sugar

Question 55

Root nodulation is beneficial to plants because plants

A) use the nodules as storehouses for nitrogen.
B) usually have limited nitrogen supplies.
C) benefit from the increased surface area provided by the nodules.
D) use the nodules to obtain phosphorus as well as nitrogen.
E) use the nodules to trap nitrogen-rich bacteria.

Question 56

Which of the following represents the correct order for the locations where rhizobia develop as a root nodule is being formed,from earliest to latest in the development?

A) Soil $\rightarrow$ root hair $\rightarrow$ cortex
B) Soil $\rightarrow$ cortex $\rightarrow$ root hair
C) Root hair $\rightarrow$ cortex $\rightarrow$ soil
D) Root hair $\rightarrow$ soil $\rightarrow$ cortex
E) Cortex $\rightarrow$ soil $\rightarrow$ root hair

Question 57

Nitrogen-fixing rhizobia can associate with the roots of which common garden plant?

A) Tomato
B) Lettuce
C) Celery
D) Pepper
E) Soybean

Question 58

What characteristic of the parasitic witchweed (Striga)provides insights into its evolutionary history?

A) It is a holoparasite and cannot conduct photosynthesis.
B) Its range is in Africa.
C) It attacks corn,which humans have historically modified through breeding.
D) It responds to a molecule similar to the one that attracts mycorrhizal fungi to plants.
E) None of the above

Question 59

The enzyme nitrogenase

A) allows normally unavailable atmospheric nitrogen to be reduced to available ammonia.
B) is responsible for oxidizing atmospheric nitrogen.
C) attacks the double bond in atmospheric nitrogen gas.
D) is naturally found in most plants.
E) allows plants to access atmospheric nitrogen directly.

Question 60

The part of the root that is most important early on in the formation of a root nodule is the

A) root cap.
B) cortex.
C) xylem.
D) phloem.
E) root hair.

Question 61

The facilitated diffusion of ions from the soil solution into root cells requires

A) an identical concentration of ions on both sides of the root cell membranes.
B) a concentration of ions outside the root cells that is lower than the concentration inside the cells.
C) the expenditure of ATP.
D) specific channel proteins in the membranes.
E) cellular respiration.

Question 62

A plant cell placed in distilled water will

A) expand until the solute potential reaches that of the distilled water.
B) become more turgid until the solute potential reaches that of the distilled water.
C) become less turgid until the solute potential reaches that of the distilled water.
D) become more turgid until the pressure potential of the cell reaches its solute potential.
E) become less turgid until the pressure potential of the cell reaches the outside water potential.

Question 63

You spot a wilted impatiens plant on the windowsill.This wilting occurs when the _______ of a plant's cells is _______.

A) water potential;high
B) turgor pressure;high
C) interior solute concentration;high
D) solute potential;high
E) turgor pressure;low

Question 64

Solute potential and pressure potential are the two components of

A) concentration.
B) turgor pressure.
C) osmotic pressure.
D) water potential.
E) None of the above

Question 65

Active transport of minerals into root cells requires energy and is necessary when

A) there is inadequate soil water to dissolve the minerals.
B) the water potential of the root cells is zero.
C) the water potential of the soil is lower than that of the root cells.
D) the concentration and charge of essential minerals in the soil make diffusion impossible.
E) All of the above

Question 66

Most water moving through the apoplast from the soil into the stele first crosses a cell membrane in the cells of the

A) root hairs.
B) cortex.
C) endodermis.
D) pericycle.
E) tracheids.

Question 67

In order to transport K⁺ ions into their cells,plants use

A) ATP to pump H⁺ out.
B) a sodium-potassium pump.
C) ATP to pump K⁺ in.
D) ATP to pump water in.
E) a proton pump to pump water in.

Question 68

Water potential

A) is the difference between the solute potential and the pressure potential.
B) is analogous to the air pressure in an automobile tire.
C) is the movement of water through a membrane.
D) determines the direction of water movement between cells.
E) is defined as 1.0 MPa for pure water under no applied pressure.

Question 69

Which statement about aquaporins is true?

A) They are necessary to protect cells from toxins.
B) They are directly involved in mineral transport.
C) They facilitate water flow through cell membranes.
D) They prevent too much water from traveling between cells.
E) They contain transport proteins.

Question 70

What happens when a large amount of water enters a plant cell?

A) Entry of the water will increase as the water potential increases.
B) The cell will eventually become turgid,with no more net entry of water.
C) The water will move toward the region of more positive water potential.
D) The turgor pressure of the cell will be reduced.
E) The entry of the water will cause increased active transport into the cell.

Question 71

Which statement about proton pumping across the cell membrane of plants is false?

A) It requires ATP.
B) The region inside the membrane becomes positively charged with respect to the region outside.
C) It enhances the movement of K⁺ ions into the cell.
D) It pushes protons out of the cell against a proton concentration gradient.
E) It can drive the secondary active transport of negatively charged ions.

Question 72

The tendency for a solution of water and solutes to take up water across a selectively permeable membrane is called

A) osmosis.
B) diffusion.
C) pressure potential.
D) turgor pressure.
E) water potential.

Question 73

The energy that drives water into root cortex cells comes most directly from

A) ATP.
B) the sun.
C) NADPH⁺.
D) bulk flow.
E) chloroplasts.

Question 74

Mineral nutrients enter the plant body directly from the soil by means of uptake

A) through the roots.
B) by the leaves.
C) from digested food molecules.
D) into vascular tissue.
E) through the stems.

Question 75

In the absence of impermeable barriers,water in one area will move to an area of _______ water potential.

A) equivalent
B) higher
C) lower
D) varying
E) decreasing

Question 76

Researchers conducting a study of leaf cell structure observe water entering the cells of a leaf from droplets on its surface.They conclude that the leaf cells have

A) a high turgor pressure due to cell wall rigidity.
B) a high,positive water potential.
C) an interior solute concentration like that of distilled water.
D) a more negative water potential than the water has.
E) reached equilibrium.

Question 77

Osmosis

A) requires ATP.
B) results in the bursting of plant cells placed in pure water.
C) can cause a cell to become turgid.
D) proceeds independently of solute concentrations.
E) continues until the pressure potential equals the water potential.

Question 78

Pumping protons (H⁺)out of a cell can trigger the movement of

A) K⁺ out of the cell and Cl^- into the cell.
B) K⁺ into the cell and Cl^- out of the cell.
C) both K⁺ and Cl^- out of the cell.
D) both K⁺ and Cl^- into the cell.
E) K⁺ into the cell,with no movement of Cl^-.

Question 79

The uptake of ions in plant cells is influenced by the

A) electrical gradient.
B) concentration gradient.
C) ionic balance.
D) pumping of H⁺.
E) All of the above

Question 80

If the soil around a tall tree is heavily contaminated by salt,the tree will likely

A) continue to grow just as it had before the salt contamination.
B) become stronger because of the increase of minerals in the soil.
C) require less water to maintain a water potential gradient.
D) die because the soil water potential will be lower than that of the roots.
E) create more xylem to accommodate the extra mineral load.