Deck 38: Plant Nutrition

Question 1

Why do plants use cotransporters instead of ion channels to transfer anions into cells?

A)Cotransporters are able to transfer anions against the membrane potential gradient,but ion channels cannot.
B)Cotransporters are able to transfer anions against the concentration gradient,but ion channels cannot.
C)Cotransporters are able to transfer anions against the proton gradient,but ion channels cannot.
D)Anions are too bulky to be transported by ion channels.

Answer 1

A

Question 2

Which of the following is not true about an essential nutrient?

A)It is necessary for plant growth and reproduction.
B)It is required for a specific structure or metabolic function.
C)It cannot be synthesized by a plant.
D)It is produced by symbiotic bacteria.
E)All of the above are correct.

Answer 2

D

Question 3

What is the function of proton pumps localized in the plant plasma membrane?

A)facilitate diffusion of ions
B)to transfer phosphorus groups from ATP to proteins
C)to transfer metal ions across the plasma membrane
D)to transfer anions across the plasma membrane
E)to create a membrane potential

Answer 3

E

Question 4

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?

A)more developed
B)less developed
C)the same
D)absent

Question 5

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

A)equal amounts of sand,clay,and humus
B)higher proportion of humus,lower amounts of clay and sand
C)higher proportion of clay,lower amounts of humus and sand
D)higher proportion of sand,lower amount of humus and clay

Question 6

You want to grow a plant that prefers neutral pH in a limestone soil.What should you add to the soil to improve plant growth?

A)sulfur (S + H₂O + 3/2 O₂↔2 H⁺ + SO₄²⁻)
B)calcium carbonate (CaCO₃ + H₂O↔HCO₃⁻ + Ca²⁺ + OH⁻)
C)aluminum hydroxide [Al(OH)₃ + 2 H+↔Al(OH)²⁺ + 2 H₂O]
D)potassium nitrate (KNO₃↔K⁺ + NO₃⁻)

Question 7

Soil leaching can cause nutrient deficiencies in the soil.Which is not a symptom of nutrient deficiency in plants?

A)chlorosis
B)necrosis of meristems
C)excess storage of chlorophyll
D)small internodes

Question 8

What is the charge on the inside of a plant cell plasma membrane?

A)positive
B)negative
C)neutral

Question 9

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

A)molecular weight of element or compound
B)the quantities required by plants
C)how they are used in metabolism
D)whether or not they are essential for plant growth
E)all of the above

Question 10

Which of the following binds to clay particles?

A)potassium ions
B)nitrate ions
C)phosphoric acid
D)sulfate ions
E)ferrous ions

Question 11

Why does planting a cover crop help conserve soil?

A)controls weed populations
B)reduces soil loss due to wind and water erosion
C)increases soil nutrients when plowed under and allowed to decompose
D)both B and C
E)all of the above

Question 12

The micronutrient iron is abundant in soil,but often unavailable to plants due to insolubility.Knowing that the reaction Fe(OH)₃ + 3 H⁺ ↔ Fe³⁺ + 3 H₂O occurs,and assuming all soil samples have same total amount of iron in them,which type of soil would you predict to have the highest amount of soluble iron?

A)neutral
B)acidic
C)alkaline
D)The amount of iron in soil does not depend on pH.

Question 13

What type of soil contains the highest amount of oxygen?

A)clay
B)sand
C)gravel
D)silt

Question 14

To understand the role of zinc in plant growth and development,you are growing a tomato plant using hydroponics.Which plant organs do you expect to have developmental defects if you provide the plant with a solution devoid of zinc?

A)leaf development only
B)stem development only
C)above ground development
D)below ground development
E)all organs will be affected

Question 15

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

A)nitrogen,potassium,phosphorus
B)nitrogen,potassium,hydrogen
C)nitrogen,sodium,chlorine
D)nitrogen,carbon,oxygen
E)nitrogen,potassium,sodium

Question 16

Where are ion channels localized?

A)in the cytoplasm
B)spanning plasma membranes
C)on the extracellular surface of plasma membranes
D)on the intracellular surface of plasma membranes

Question 17

What is the trade-off in nutrient availability concerning clay soils?

A)Anions are less likely to leach out of the soil but difficult for plants to extract.
B)Cations are less likely to leach out of soil but are difficult for plants to extract.
C)high in anion concentration,but clay soils do not hold water well so anions leach away
D)high in both anions and cations,but low pH makes root uptake of ions difficult

Question 18

Which of the following experiments is able to determine if an element is essential for plant growth?

A)measuring the amount of the element stored in plant tissues
B)measuring the amount of the element in the soil before and after plant growth
C)measuring the weight of the plant and soil before and after plant growth
D)growth of a plant by hydroponics without the element
E)all of the above

Question 19

To determine the requirement of chlorine for plant growth,you decided to perform a hydroponic experiment.What solution are you going to use to grow control plants for comparison with chlorine-derived plants?

A)pure water
B)water with chlorine
C)water with macronutrients and chlorine
D)water with micronutrients and chlorine
E)water with essential elements

Question 20

Which elements are responsible for the greater part of plant wet weight?

A)carbon,nitrogen,oxygen
B)carbon,nitrogen,phosphorus
C)carbon,oxygen,hydrogen
D)carbon,hydrogen,potassium
E)carbon,nitrogen,potassium

Question 21

What kind of climate is most often associated with epiphytic plants?

A)warm
B)humid
C)sunny
D)all of the above

Question 22

Figure 38.2

The IRT1 gene is responsible for most of the iron uptake activity in roots (Vert et al. ,Plant Cell 14 [2002]:
1223-33).To determine the specificity of the IRT1 transporter in Arabidopsis plants,researchers measured the concentration of manganese,zinc,copper,and cobalt contained in wild-type and irt1-1 mutant plants.What conclusions about IRT1 specificity can you draw from the above data?

A)Under iron-deficient conditions,IRT1 is highly specific for Fe.
B)Under iron-deficient conditions,IRT1 is important for the transport of iron and copper.
C)IRT1 is important for the transport of iron and copper independent of iron concentration.
D)Under iron-deficient conditions,IRT1 is necessary for the transport of iron,zinc,manganese,and cobalt.
E)IRT1 participates in the transport of iron,zinc,manganese,and cobalt independent of iron concentration.

Question 23

Give two reasons that relatively few plants thrive in bogs.

Question 24

What is a typical habitat for carnivorous plants?

A)wet areas with high salinity
B)wet areas with high levels of humus
C)wet areas with low decomposition rates
D)dry areas with low levels of available oxygen
E)dry areas with high levels of peat

Question 25

After mutagenesis and screening take place,you have found a mutant that is able to grow in soil with high copper content.Protein analysis shows that the concentration of metallothioneins in the mutant is different from that in normal plants.How does the concentration of metallothioneins likely differ in the mutant relative to the normal plant?

A)Metallothioneins are absent in the mutant.
B)The concentration of metallothioneins is greater in the mutant.
C)The concentration of metallothioneins is lower in the mutant.
D)Metallothioneins are the most abundant proteins in the mutant.

Question 26

After mutagenesis,the bacteria Sinorhizobium meliloti became unable to colonize Medicago truncatula plants due to the absence of recognition by the host plant.Which of the following genes is most likely the site of mutation?

A)nitrogenase
B)flavonoid-synthesizing enzyme
C)Nod factors
D)leghemoglobin
E)peptidoglycans of the bacterial cell wall

Question 27

What is phytoremediation?

A)use of plants to remove heavy metals from soils
B)use of plants to remove excess CO₂ from the atmosphere and reduce global warming
C)use of plants to conserve soil nutrients
D)use of plants to prevent soil loss due to water and wind

Question 28

What 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)Plants receive photosynthetic products in exchange for living in root nodules.
D)Plants receive nitrogen and phosphorus,and fungi receive photosynthetic products.

Question 29

What is the right sequence of steps during infection of plants by nitrogen-fixing bacteria?

A)Rhizobia release Nod factors;roots release flavonoids;rhizobia proliferate inside of root hair;infection thread grows into the root cortex;nodule forms.
B)Rhizobia release flavonoids;roots release Nod factors;rhizobia proliferate inside of root hair;infection thread grows into the root cortex;nodule forms.
C)Roots release flavonoids;rhizobia release Nod factors;rhizobia proliferate inside of root hair;nodule forms;infection thread grows into the root cortex.
D)Roots release flavonoids;rhizobia release Nod factors;rhizobia proliferate inside of root hair;infection thread grows into the root cortex;nodule forms.
E)Nodule forms;infection thread grows into the root cortex;rhizobia proliferate inside of root hair;rhizobia release flavonoids and Nod factors.

Question 30

Figure 38.1

Iron shortage is the most common human nutritional deficiency in the world.Plants are the major source of iron in most diets,so researchers are interested in understanding their mechanism of iron intake and in developing iron-rich crops.Recently researchers showed (Vert et al. ,IRT1,an Arabidopsis transporter essential for iron uptake from the soil and for plant growth.Plant Cell 14 [2002]:
1223-33)that under iron-deficient conditions,the IRT1 gene is responsible for most of the iron uptake activity in roots.To demonstrate the importance of IRT1 for iron accumulation,researchers measured leaf iron content in irt1-1 mutants containing deactivated IRT1.Mutant plants were grown in iron-poor soil (irt1-1 in graph)and soil rich with iron (irt1-1 +Fe in graph).Wild-type (WT)plants grown in iron-poor soil were used as a control.Which of the graphs represent the data researchers might have received in their experiment?

Question 31

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?

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

Question 32

Researchers are interested in improving crop plants to enable them to form a symbiotic relationship with nitrogen-fixing bacteria.What genes would you need to transfer to a plant that does not associate with rhizobia to enable it to do so?

A)genes responsible for the synthesis of flavonoids and receptor for Nod factors
B)genes responsible for the synthesis of Nod factors and receptor for flavonoids
C)receptor for Nod factors and leghemoglobin gene
D)genes responsible for the synthesis of Nod factors and receptor for flavonoids and leghemoglobin gene
E)None of the above is sufficient,since many more genes need to be transferred.

Question 33

Both ectomycorrhizal fungi and rhizobia are able to supply plants with usable forms of nitrogen.From what sources do rhizobia and ectomycorrhizal fungi that are associated with plants obtain nitrogen?

A)Fungi absorb N₂ from the atmosphere,and rhizobia obtain nitrogen by decomposition of organic material.
B)Fungi obtain nitrogen by decomposition of organic material,and rhizobia absorb N₂ from the atmosphere.
C)They both absorb ammonia from soil,which they nitrify to NO₂⁻.
D)They both obtain nitrogen by decomposition of organic material.

Question 34

Which of the following statements is not true about tropical soils?

A)They are nutrient poor.
B)They are alkaline.
C)They contain high concentration of iron oxides.
D)They are rich in soil bacteria.
E)All of the above are correct.

Question 35

Which of the following is the most energy-demanding process?

A)reduction of N₂ to NH₃
B)reduction of NO₃⁻ to NH₃
C)nitrification of NH₃ to NO₂⁻
D)nitrification of NO₂⁻ to NO₃⁻
E)denitrification of NO₃⁻ to N₂

Question 36

After mutagenesis and screening,you have found a mutant that is able to grow in soil with high salt content.Chemical analysis showed that this plant has a decreased amount of Na⁺ relative to normal plants.What kind of mutation do you predict this plant contains?

A)mutation in the plasma membrane sodium channel
B)mutation in the metallothioneins
C)mutation in the tonoplast sodium channel
D)mutation in the tonoplast antiporter