Deck 6: Plant Adaptations to the Environment

Question 1

Under ideal conditions, the allocation of carbon to the further production of ________ tissue will promote the fastest growth.

Answer 1

leaf

Question 2

Briefly outline the trade-off a shade-tolerant species makes in order to survive in low light.

Answer 2

Their physiology, morphology, and carbon allocation allow them to survive and grow in low light. However, these same traits limit their ability to increase photosynthesis and take advantage of higher light conditions if they become present.

Question 3

To survive, grow, and reproduce, plants must maintain a ________ carbon balance.

Answer 3

positive

Question 4

The diffusion of CO₂ in water is ________ than the diffusion of CO₂ in air.

Question 5

The light level at which the rate of carbon uptake in photosynthesis equals the rate of carbon loss in respiration is the ________ point.

Question 6

The ratio of carbon fixed (photosynthesis)per unit of water lost (transpiration)is called the ________.

Question 7

________ are openings in the leaves of terrestrial plants that allow for the uptake of CO₂.

Question 8

Terrestrial plants exchange heat by convection and ________.

Question 9

The process of water loss by plants through stomata is called ________.

Question 10

The enzyme that catalyzes carboxylation during photosynthesis is called ________.

Question 11

The stage of photosynthesis during which chlorophyll absorbs light energy is called the ________.

Question 12

The force exerted outward on a plant cell wall by the water contained in the cell is called ________.

Question 13

Leaf shape and size influences the thickness and dynamics of the ________ layer and therefore the ability of plants to exchange heat through ________.

Question 14

Once dissolved in water, the CO₂ molecule reacts with water to form ________.

Question 15

All life is ________ based.

Question 16

________ tissue provides vertical support to the plant and elevates leaves.

Question 17

The portion of sunlight that is available to plants for photosynthesis is called ________.

Question 18

The process of photosynthesis in plants occurs in specialized cells within the leaf called ________ cells.

Question 19

The tendency of a solution to attract water molecules from areas of high to low concentration is called its ________.

Question 20

A plant growing in sun is expected to have a ________ maximum photosynthetic rate than a plant growing in shade.

Question 21

The process of converting CO₂ into organic molecules is called

A)respiration.
B)assimilation.
C)photosynthesis.
D)none of the above.

Question 22

In the C₃ photosynthetic pathway, the enzyme Rubisco catalyzes the reaction called

A)chemosynthesis.
B)carboxylation.
C)photoreduction.
D)none of the above.

Question 23

Spongy passages, or ________, allow for the transport of oxygen and other gases to submerged roots.

Question 24

Plants adapted to saline habitats are called ________.

Question 25

Organisms that derive their energy from sunlight are referred to as

A)heterotrophs.
B)chemotrophs.
C)autotrophs.
D)none of the above.

Question 26

Photons are absorbed by pigments in antennae which pass the energy to reaction centre chlorophylls via

A)Rubisco.
B)resonance transfer.
C)electron transfer.
D)photon shuffling.

Question 27

Many plants adapted to arid environments utilize the ________ photosynthetic pathway to fix CO₂ during the night.

Question 28

Plants determine when to flower based on environmental cues. Identify three categories of plants and what cues they use.

Question 29

Some plants have the ability to tolerate extreme cold, known as ________.

Question 30

The primary drawback of the C₃ photosynthetic pathway is that

A)it requires large amounts of phosphorus and potassium.
B)it requires a large amount of nitrogen.
C)the enzyme Rubisco can also act as an oxygenase.
D)the enzyme Rubisco is subject to damage by UV radiation.

Question 31

Nutrients that are needed by plants in large amounts are called ________.

Question 32

________ is the component of relative growth rate that represents the leaf area per unit of plant weight.

Question 33

In tropical regions with distinct wet and dry seasons, plants that drop their leaves at the onset of the dry season are termed ________.

Question 34

C₄ plants use the enzyme ________ to fix CO₂.

Question 35

The value of PAR above which no further increase in photosynthesis occurs is referred to as the

A)photoinhibition point.
B)chlorophyll compensation point.
C)light compensation point.
D)light saturation point.

Question 36

The ratio of surface area to weight for a leaf is called the ________.

Question 37

Carbon, from which life is constructed, is derived from

A)atmospheric carbon dioxide.
B)respiration.
C)decomposition.
D)the consumption of other organisms.

Question 38

Much of the nitrogen taken in by a plant is used to synthesis the molecules Rubisco and ________.

Question 39

________ expresses the change in size of an individual during the observed period of time as a function of the size of the individual.

Question 40

The pigment that absorbs light energy (photons)in photosynthesis is

A)Rubisco.
B)chlorophyll.
C)PEP.
D)CAM.

Question 41

Net CO₂ uptake by a plant is greatest

A)when PAR equals zero.
B)at the light compensation point.
C)during photoinhibition.
D)at the light saturation point.

Question 42

Compared with a shade-intolerant plant, a shade-tolerant plant

A)has a greater SLA.
B)grows faster.
C)requires a higher intake of CO₂ to balance losses of CO₂ from respiration.
D)allocates very little carbon to leaf tissue.

Question 43

As temperatures continue to rise, the photosynthetic rate reaches a maximum related to

A)the temperature response of Rubisco.
B)the thickness of the boundary layer.
C)soil temperature.
D)oxygen availability.

Question 44

Submerged aquatic plants can take up CO₂ from the water in all of the following ways, EXCEPT

A)diffusion through stomata.
B)direct diffusion of ambient CO₂ from water across cell membranes.
C)active transport of bicarbonate into the leaf followed by conversion to CO₂.
D)excretion of carbonic anhydrase into the water, followed by uptake of the resulting CO₂.

Question 45

Compared with plants growing in high light, plants growing in shaded environments tend to produce ________ Rubisco.

A)equal amounts of
B)more
C)less
D)a different type of

Question 46

Which of the following statements is FALSE?

A)PEP carboxylase has a low affinity for oxygen.
B)CO₂ is initially fixed into oxaloacetate (OAA)in the mesophyll cell.
C)C₄ plants have a lower water use efficiency than C₃ plants.
D)C₄ plants are mostly grasses.

Question 47

Which of the following enters a plant via its stomata?

A)CO₂
B)H₂O
C)phosphorus
D)O₂

Question 48

The effect of solute concentration on the state of water loss from plant cells is called

A)water potential.
B)matric potential.
C)osmotic potential.
D)osmotic pressure.

Question 49

A plant adapted to a dry, sunny environment might be expected to have

A)thin, flexible leaves.
B)large leaves.
C)a minimal root system.
D)small leaves.

Question 50

Shaded leaves of a plant in partial sunlight, exhibit ________ when they respond as if they themselves have been directly exposed to high light.

A)sun adaptation
B)shade tolerance
C)the far-red response
D)systemic acquired photoprotection

Question 51

A CO₂ gradient between the inside and outside of a leaf is maintained during photosynthesis because

A)energy is expended by the plant to maintain the CO₂ gradient.
B)the CO₂ concentration outside of the leaf is always increasing.
C)the CO₂ concentration in the mesophyll is constantly decreasing.
D)the stomata close whenever more CO₂ is needed.

Question 52

Overall, water movement from the soil, through plant tissues, and finally to the atmosphere through transpiration is driven by a gradient of

A)water potential.
B)osmotic pressure.
C)water temperature.
D)specific leaf area.

Question 53

________ temperature controls the rates of photosynthesis and respiration.

A)Soil
B)Air
C)Leaf
D)Root

Question 54

Which of the following is an incorrect statement?

A)A large leaf will maximizes light interception.
B)A deeply lobed leaf will minimize heat exchange with the atmosphere.
C)A thick leaf will reduce loss of water via transpiration
D)A leaf with a high SLA will generally be thin and flexible.

Question 55

Which of the following conditions is required for a continued movement of water from the soil into and through a plant via transpiration?

A)ψₐtm < ψᵣₒₒt < ψlₑₐf < ψsₒᵢl
B)ψₐtm < ψlₑₐf < ψᵣₒₒt < ψsₒᵢl
C)ψsₒᵢl < ψᵣₒₒt < ψlₑₐf < ψₐtm
D)ψsₒᵢl < ψₐtm < ψᵣₒₒt < ψlₑₐf

Question 56

Some aquatic plants can utilize HCO₃⁻ as a carbon source but must first convert it into CO₂ by using the enzyme

A)carboxylase.
B)Rubisco.
C)oxygenase.
D)carbonic anhydrase.

Question 57

When resources are plentiful, plants will allocate the most carbon to the production of

A)roots.
B)stems.
C)leaves.
D)flowers.

Question 58

Net carbon uptake per unit time by a plant is directly related to

A)the difference between photosynthetic rate and respiration rate.
B)photosynthetic rate.
C)respiration rate.
D)the difference between photosynthetic rate and decomposition rate.

Question 59

Compared with terrestrial plants, submerged aquatic plants lack

A)leaves.
B)chlorophyll.
C)stomata.
D)stems.

Question 60

Carbon balance focuses on the balance between

A)uptake of CO₂ in photosynthesis and loss of heat via evapotranspiration.
B)loss of CO₂ through respiration and gain of nutrients.
C)loss of H₂O balanced with the gain of CO₂ via transpiration.
D)uptake of CO₂ in photosynthesis balanced with the loss of CO₂ during respiration.

Question 61

Photoinhibition is the negative effect of high light levels on respiration.

Question 62

CAM plants fix CO₂

A)ᵢntₒ ₒₓₐlₒₐcₑtₐtₑ ₍OAA₎.
B)ₐt nᵢght.
C)in mesophyll cells.
D)only when it is raining.

Question 63

In nature, water potential values (ψ)typically range from zero to increasingly positive values.

Question 64

A plant takes in water and loses carbon dioxide through its open stomata.

Question 65

Which of the following is considered a plant adaptation to low-nutrient environments?

A)faster growth rate
B)decreased root production
C)increased leaf longevity
D)none of the above

Question 66

Photosynthesis produces more water than it uses.

Question 67

The C₄ photosynthetic pathway is most common among plants inhabiting ________ habitats.

A)cool
B)high-latitude
C)high-altitude
D)hot

Question 68

At light levels below the light compensation point, the rate of carbon loss due to respiration exceeds the rate of uptake in the process of photosynthesis.

Question 69

Which of the following elements is considered a plant micronutrient?

A)iron
B)nitrogen
C)phosphorus
D)oxygen

Question 70

The drier the air outside a leaf, the faster water will be lost from the leaf through the stomata.

Question 71

A ________ is a daily pattern of physiological response to an environmental cycle.

A)biological clock
B)circadian rhythm
C)photoperiod
D)jet-lag event

Question 72

Plants can reduce water loss by

A)closing their stomata.
B)growing larger leaves.
C)growing more slowly.
D)increasing photosynthesis.

Question 73

Some plant species are able to release ________ from flooded or submerged roots to increase aeration and prevent anaerobic conditions.

A)methane
B)ethylene
C)oxygen
D)nitrogen

Question 74

An Acacia seedling grown in shade (50% full sun)is expected to have a ________ net assimilation rate (NAR)and ________ leaf area ratio (LAR)than an Acacia seedling grown in full sun.

A)higher; higher
B)lower; lower
C)lower; higher
D)higher; lower

Question 75

All life on Earth is carbon based.

Question 76

Photosynthesis transforms oxygen and carbon dioxide into carbohydrates and water.

Question 77

Leaf area ratio (LAR)is the product of specific leaf area (SLA)and

A)net assimilation rate (NAR).
B)relative growth rate (RGR).
C)maximum net photosynthesis.
D)leaf weight ratio (LWR).

Question 78

Pneumatophores are typical of plants (particularly trees)

A)in arid environments.
B)exposed to fluctuating water levels.
C)flooded once each year.
D)in salt marshes.

Question 79

All the following are plant adaptations to low temperatures, EXCEPT

A)shedding leaves at the onset of cold weather.
B)production of antifreeze molecules.
C)a shifting of Tₒpt.
D)an increased photosynthetic rate to heat leaves.

Question 80

The light and dark reactions of photosynthesis occur in different areas of the chloroplast.