Deck 34: Leaf Structure and Function

Question 1

Which of the following are responsible for opening and closing the stoma?

A) Companion cells
B) Cuticle cells
C) Cork cells
D) Sclerenchyma cells
E) Guard cells

Answer 1

E

Question 2

Stomata are:

A) waxy layers that cover leaves.
B) openings in the leaf epidermis.
C) extensions of bundle sheaths.
D) particularly numerous on the upper epidermis.
E) guarded by two stipule cells.

Answer 2

B

Question 3

Mesophyll cells are:

A) arranged tightly together.
B) separated by intercellular spaces.
C) responsible for the opening and closing of stomata.
D) devoid of chloroplasts.
E) covered by a waxy cuticle, which they secrete.

Answer 3

B

Question 4

The middle portion of a leaf that is sandwiched between the upper and the lower epidermis is called the:

A) mesoderm.
B) middle lamella.
C) mesophyte.
D) bundle sheath.
E) mesophyll.

Question 5

Figure 34-1 ​

Which of the following is a leaf arrangement in which three or more leaves grow at each node?

A) Netted
B) Parallel
C) Whorled
D) Opposite
E) Alternate

Question 6

Which of the following reduces water loss from plant epidermal cell exterior walls?

A) Cellulose
B) Lignin
C) Hemicellulose
D) Starch
E) Cuticle

Question 7

Leaves:

A) represent a fairly small fraction of the overall metabolic budget for a plant.
B) depend on the roots to supply CO₂.
C) are the main photosynthetic organ of most plants.
D) are the main site of water uptake in plants.
E) prevent CO₂ and O₂ from entering the plant.

Question 8

Which of the following is a leaf arrangement in which there is one leaf at each node?

A) Netted
B) Parallel
C) Whorled
D) Opposite
E) Alternate

Question 9

Compound leaves have:

A) parallel veins instead of netted veins.
B) alternate leaf attachment instead of opposite leaf attachment.
C) palmately netted leaves instead of pinnately netted leaves.
D) two or more leaflets instead of a single blade.
E) many leaves per plant instead of a single leaf per plant.

Question 10

Figure 34-2 ​

The photosynthetic ground tissue of the leaf is termed which of the following?

A) Guard cells
B) Epidermal cells
C) Stoma
D) Mesophyll
E) Subsidiary cells

Question 11

Floating leaves of aquatic plants have:

A) stomata only on the lower epidermis.
B) stomata only on the upper epidermis.
C) stomata on both the lower and the upper epidermis.
D) no stomata on the epidermis.
E) stomata only within the mesophyll.

Question 12

Usually the only epidermal cells with chloroplasts are:

A) stomata.
B) stoma.
C) parenchyma.
D) guard cells.
E) all of these.

Question 13

The area of the angle between the stem and the petiole is referred to as the:

A) axil.
B) blade.
C) petiole.
D) stipule.
E) trichome.

Question 14

Photosynthesis occurs mainly in the leaf's:

A) subsidiary cells.
B) bundle sheath extensions.
C) palisade mesophyll.
D) trichomes.
E) vascular bundles.

Question 15

Looking for which of the following is useful for determining whether a plant has simple or compound leaves?

A) Stipules
B) Veins
C) Petioles
D) Nodes
E) Axillary buds

Question 16

Figure 34-1 ​

Which of the following is a leaf arrangement in which two leaves grow at each node?

A) Netted
B) Parallel
C) Whorled
D) Opposite
E) Alternate

Question 17

Trichomes on plants are responsible for:

A) preventing water absorption on leaf surfaces.
B) deterring herbivores.
C) absorbing salts absorbed from the air.
D) the waxy structures on the petiole.
E) facilitating gas exchange.

Question 18

Figure 34-2 ​

The organization of tissues in the accompanying figure is characteristic of a:

A) stem.
B) spine.
C) leaf blade.
D) petiole.
E) bud scale.

Question 19

Which statement describes the leaf epidermis?

A) Its cells lack chloroplasts.
B) Some of its cells perform photosynthesis.
C) Its cell walls are thin.
D) Its cells are opaque.
E) It has only a single layer.

Question 20

Figure 34-2 ​

In the accompanying figure, the palisade mesophyll is labeled with the number:

A) 1
B) 2
C) 3
D) 6
E) 9

Question 21

Which structure or structures function to open and close the stomata?

A) Cuticle
B) Mesophyll
C) Palisade cells
D) Guard cells
E) Chloroplasts

Question 22

The process of photosynthesis involves the conversion of:

A) oxygen and water into sugar.
B) sugar into starches and cellulose.
C) oxygen and sugar into water.
D) carbon dioxide and water into sugar.
E) sugar and water into lipids.

Question 23

The pigment involved in stomatal opening and closing is which of the following colors?

A) Red
B) Orange
C) Yellow
D) Green
E) Blue

Question 24

Which change is most important in stomatal closing?

A) Declining sucrose concentrations
B) Rising sucrose concentrations
C) Rising potassium concentrations
D) Declining potassium concentrations
E) Declining chloride concentrations

Question 25

If a plant were placed in continual darkness, it would continue to open and close its stomata at approximately the same time each day. This phenomenon is governed by:

A) annual rhythms.
B) floral clocks.
C) transpiration.
D) temporal mechanisms.
E) circadian rhythms.

Question 26

Which of the following are the only plant epidermal cells that are photosynthetic?

A) Guard cells
B) Epidermal cells
C) Stoma
D) Mesophyll
E) Subsidiary cells

Question 27

The rate of transpiration decreases under which of the following conditions?

A) Increased wind
B) Increased humidity
C) Increased temperature
D) Presence of sunlight
E) An increase in dry air

Question 28

Which of the following wavelengths of light trigger stomatal opening?

A) 300 to 400 nm
B) 400 to 500 nm
C) 500 to 600 nm
D) 600 to 700 nm
E) 700 to 800 nm

Question 29

Guttation typically occurs:

A) at noon.
B) at dawn.
C) at dusk.
D) at night.
E) when the sun is at its peak.

Question 30

Photosynthesis reduces the leaf's internal concentration of:

A) hydrogen.
B) carbon dioxide.
C) nitrogen.
D) oxygen.
E) sugars and starches.

Question 31

The needles of pines and other conifers are adapted to:

A) conserve water.
B) defend against herbivores.
C) reduce the effects of intense sunlight.
D) reduce the effects of snow and ice.
E) reduce the effects of wind.

Question 32

The primary function of the spongy mesophyll is to allow which of the following processes?

A) Gas diffusion, particularly CO₂, within the leaf
B) Light capture
C) Energy production
D) Energy storage
E) Water transport

Question 33

Which of the following is true of monocot leaves?

A) Many monocots have a distinct palisade layer.
B) Many monocots lack a petiole.
C) Many monocots have a distinct spongy layer.
D) Many monocot leaves are broad.
E) Many monocot leaves have netted venation.

Question 34

After light triggers the activation proton pumps, what happens next in the leaf?

A) Chloride ions are pumped out of the guard cells.
B) Hydrogen ions are actively transported out of guard cells.
C) Potassium ions diffuse into guard cells.
D) Chloride ions diffuse out of guard cells.
E) Water moves by osmosis into guard cells.

Question 35

The primary function of spongy mesophyll is:

A) photosynthesis.
B) transpiration.
C) to allow diffusion of gases.
D) transport of substances.
E) transport of water.

Question 36

Monocot leaves typically have:

A) alternately palmate venation.
B) netted venation.
C) parallel venation.
D) alternately pinnate venation.
E) no venation.

Question 37

Which of the following contains dissolved sugars?

A) Xylem
B) Phloem
C) Stoma
D) Mesophyll
E) Stipules

Question 38

Opening and closing of the stomata:

A) occur during prolonged periods of drought.
B) occur when there is a high concentration of carbon dioxide in the leaf.
C) are under hormonal control.
D) are triggered by darkness.
E) are controlled by the changes in shape of the companion cells.

Question 39

Eudicot leaves typically have:

A) alternately palmate venation.
B) netted venation.
C) parallel venation.
D) alternately pinnate venation.
E) no venation.

Question 40

The process by which water is lost by evaporation from aerial plant parts is known as:

A) vaporization.
B) photosynthesis.
C) guttation.
D) transpiration.
E) abscission.

Question 41

Modified leaves that protect meristematic tissue at the tips of woody plants are known as:

A) bulbs.
B) bud scales.
C) spines.
D) tendrils.
E) scale scars.

Question 42

Explain the difference between guttation and transpiration.

Question 43

Identify and describe:
A. three different ways in which leaves can be arranged on stems, and list one example for each.

B. three different venation patterns in leaves and whether each is characteristic of eudicots or monocots.

Question 44

A leaf without a blade is said to be sessile.

Question 45

One benefit of transpiration is that it:

A) concentrates nutrients in plant leaves.
B) distributes nutrients throughout the plant.
C) moves water from the atmosphere to the plant.
D) is responsible for warming plants.
E) brings in water from the soil.

Question 46

Excess transpiration:

A) may be harmful to a plant.
B) causes an increase in turgor pressure.
C) is a synonym for precipitation.
D) occurs mainly in the winter.
E) is automatically counteracted by absorbing water from the soil.

Question 47

Leaf abscission:

A) occurs as a response to increased temperatures in temperate climates.
B) occurs as a response to dry conditions in tropical climates.
C) involves the formation of a tendril at the base of the petiole.
D) occurs year-round on deciduous plants.
E) does not occur in conifers.

Question 48

Most carnivorous plants grow in poor soil that is deficient in certain essential elements, especially which of the following elements?

A) Potassium
B) Sodium
C) Nitrogen
D) Oxygen
E) Sulfur

Question 49

The release of liquid water by leaves when soil moisture is high is known as:

A) vaporization.
B) photosynthesis.
C) guttation.
D) transpiration.
E) abscission.

Question 50

The spines of a cactus are actually modified:

A) branches.
B) stems.
C) leaves.
D) roots.
E) trichomes.

Question 51

Which of the following have tendrils that are specialized stems (NOT specialized leaves)?

A) Peas
B) Cucumbers
C) Squash
D) Sweet peas
E) Ivy

Question 52

Which event is associated with leaf abscission?

A) Chlorophyll breaks down.
B) Anthocyanins degrade.
C) Carotenoids are transported from the leaves.
D) Sugars accumulate in the leaves.
E) Leaves turn dark green.

Question 53

The area where the petiole detaches from the stem is referred to as the:

A) abscission zone.
B) middle lamella.
C) bundle sheath extension.
D) terminal bud.
E) bud scale scar.

Question 54

Underground stems with fleshy leaves used for storage of water and food are known as:

A) tendrils.
B) spines.
C) bulbs.
D) buds.
E) stipules.

Question 55

An alternate leaf arrangement is one in which there is one leaf per node.

Question 56

Parallel venation is characteristic of eudicot leaves.

Question 57

Insectivorous plants:

A) typically grow in nutrient-rich soil.
B) enhance a poor supply of CO₂ through capturing prey.
C) use modified leaves to trap their prey.
D) require symbiotic insects and insect larvae to digest their prey.
E) require microorganisms to digest their prey.

Question 58

Compare the leaf structure of monocots and eudicots.

Question 59

Subsidiary cells are the only epidermal cells that have chloroplasts.

Question 60

Which of the following substances may protect leaves against damage by ultraviolet radiation after abscission?

A) Anthocyanins
B) Coumarins
C) Auxins
D) Coumadins
E) Gibberellins

Question 61

A spine is a modified branch.

Question 62

Explain how blue light triggers the movement of hydrogen and potassium ions across the membranes of guard cells and how this causes opening and closing of the stomata.

Question 63

Palisade mesophyll is a tissue typically found on the side of the leaf toward the upper epidermis.

Question 64

Describe the benefits of transpiration to plants.

Question 65

The bundle sheath typically surrounds the larger veins.

Question 66

Red light has a wavelength that is the most effective for triggering stomatal opening.

Question 69

Guttation is the process most responsible for moving water and minerals through the plant.

Question 72

Leaf abscission is initiated and orchestrated by the hormone abscisic acid.

Question 73

A cross section of a monocot leaf typically shows veins in both cross-section and lengthwise section.

Question 75

Explain how the structure of a leaf contributes to the function of photosynthesis.

Question 76

Stomata close as a result of water moving into guard cells.

Question 77

Most transpiration occurs through stomata.

Question 80

Transpiration increases at lower temperatures.