Ch 27: Plant Form, Function, and Evolutionary History

Question 1

Desiccation

Answer 1

Excessive water loss; drying out.

Question 2

Desiccation Tolerance

Answer 2

A suite of biochemical traits that allows cells to survive extreme dehydration by minimizing damage to membranes and macromolecules.

Question 3

Lycophytes

Answer 3

A monophyletic group of spore-dispersing vascular plants that are the sister group to all other vascular plants.

Question 4

Ferns and Horsetails

Answer 4

A monophyletic group of vascular plants in which both the gametophyte and sporophyte generations are free living and that disperse by spores.

Question 5

Gymnosperms

Answer 5

Seed plants whose ovules are not enclosed in a carpel; gymnosperms include pine trees and other conifers, as well as cycads, gnetophytes, and ginkgo.

Question 6

Angiosperms

Answer 6

The flowering plants; a monophyletic group of seed plants characterized by flowers, double fertilization, and fruits.

Question 7

Shoots

Answer 7

The collective name for the leaves, stems, and reproductive organs; the major aboveground organ systems of vascular plants.

Question 8

Epidermis

Answer 8

In mammals, the outer layer of skin, which serves as a water-resistant, protective barrier. In plants, the outermost layer of cells in leaves, young stems (lacking secondary growth), and roots. In general, the outer layer of the body.

Question 9

Vascular Tissue

Answer 9

A plant tissue that extends from leaves to roots and allows water and nutrients to move by bulk flow.

Question 10

Xylem

Answer 10

Vascular tissue consisting of lignified conduits that transports water and nutrients from the roots to the leaves.

Question 11

Phloem

Answer 11

The vascular tissue that transports carbohydrates from leaves to the rest of the plant body.

Question 12

Ground Tissue

Answer 12

In plants, all tissues other than the epidermis and vascular tissues.

Question 13

Parenchyma

Answer 13

In plants, describes thin-walled cells that carry out a variety of functions, including photosynthesis and storage; capable of further cell division if stimulated.

Question 14

Mesophyll

Answer 14

A leaf tissue of loosely packed photosynthetic cells.

Question 15

Veins

Answer 15

In plants, the system of vascular conduits within the leaf; in animals, the large, low-pressure vessels that return blood to the heart.

Question 16

Transpiration

Answer 16

The loss of water vapor from leaves.

Question 17

Cuticle

Answer 17

In plants, a protective layer of a waxy substance secreted by epidermal cells that limits water loss; in animals, an exoskeleton that covers the bodies of invertebrates such as nematodes and arthropods.

Question 18

Stomata

Answer 18

Pores in the epidermis of a leaf that regulate the diffusion of gases between the interior of the leaf and the atmosphere.

Question 19

Guard Cells

Answer 19

One of two cells surrounding the central pore of a stoma.

Question 20

Crassulacean acid metabolism (CAM)

Answer 20

A mechanism in plants that helps balance carbon dioxide gain and water loss by capturing carbon dioxide into 4-carbon organic acids at night, when transpiration rates are low, and then using it to supply the Calvin cycle during the day while stomata remain closed.

Question 21

C4 Plants

Answer 21

A plant in which carbon dioxide is incorporated into 4-carbon organic acids in mesophyll cells that are then used to supply the Calvin cycle in bundle sheath cells; results in the suppression of photorespiration.

Question 22

C3 Plants

Answer 22

A plant that does not use 4-carbon organic acids to supply the Calvin cycle with carbon dioxide.

Question 23

Tracheids

Answer 23

A unicellular xylem conduit.

Question 24

Vessels

Answer 24

A multicellular xylem conduit.

Question 25

Vessel Element

Answer 25

An individual cell that is part of a xylem vessel for water transport in plants.

Question 26

Water Potential

Answer 26

A parameter that combines all of the factors that influence the movement of water, such as pressure, osmosis, and gravity.

Question 27

Cavitation

Answer 27

The abrupt replacement of liquid water in a xylem conduit by water vapor, which prevents water from being pulled through the xylem by transpiration.

Question 28

Sources

Answer 28

In plants, a region that supplies carbohydrates to other parts of the plant.

Question 29

Sinks

Answer 29

In plants, any portion of the plant that imports carbohydrates to fuel growth and respiration, such as a root, young leaf, or developing fruit.

Question 30

Companion Cells

Answer 30

In angiosperms, a cell that carries out cellular functions such as protein synthesis for sieve tubes.

Question 31

Phloem Sap

Answer 31

The sugar-rich solution that flows through both the lumen of the sieve tubes and the sieve plate pores.

Question 32

Sieve Tubes

Answer 32

A multicellular unit composed of sieve elements that are connected end to end, through which phloem transport takes place.

Question 33

Sieve Plates

Answer 33

In angiosperm phloem, a modified end wall with large pores that links sieve elements.

Question 34

Rhizosphere

Answer 34

The soil layer that surrounds actively growing roots.

Question 35

Root Hairs

Answer 35

A slender outgrowth produced by epidermal cells that greatly increases the surface area of the root.

Question 36

Cortex

Answer 36

In a stem, the region between the epidermis and the vascular bundles, composed of parenchyma cells. In the mammalian brain, the highly folded outer layer of gray matter, about 4 mm thick, made up of densely packed neuron cell bodies and their dendrites. In the mammalian renal system, the outer layer of the kidney.

Question 37

Endodermis

Answer 37

In plants, a layer of cells surrounding the xylem and phloem at the center of the root that controls the movement of nutrients into the xylem. Also, the inner lining of the cnidarian body.

Question 38

Casparian Strip

Answer 38

A band of hydrophobic material that encircles each cell of the endodermis of a root, forcing water and solutes to reach the xylem by passing through the cytoplasm of endodermal cells.

Question 39

Mycorrhizae

Answer 39

Fungi that live symbiotically among roots, enhancing nutrient uptake by the plants.

Question 40

Ectomycorrhizae

Answer 40

One of the two main types of mycorrhizae; ectomycorrhizae produce a thick sheath of fungal cells (hyphae) that surround the root tip, as well as hyphae that grow between, but do not penetrate, cells in the interior of the root.

Question 41

Endomycorrhizae

Answer 41

One of the two main types of mycorrhizae; endomycorrhizal hyphae penetrate into root cells, where they produce highly branched structures (arbuscules) that provide a large surface area for nutrient exchange.

Question 42

Nitrogen Fixation

Answer 42

The process by which some Bacteria and Archaea convert nitrogen gas (N2) into ammonia (NH3), a form biologically useful to primary producers.

Question 43

Root Nodule

Answer 43

A structure, formed by dividing root cells, in which nitrogen-fixing bacteria live.

Question 44

T/F: Like bryophytes, the leaves of most angiosperms demonstrate desiccation tolerance and can survive long periods without water.

Answer 44

False

Question 45

T/F: Tracheids are short and narrow, whereas vessel elements can be much longer and wider.

Answer 45

True

Question 46

The forces that result in bulk flow of phloem sap originate when _____ is actively pumped into the phloem from _____ cells in the leaf, which causes _____ to enter via _____.

Answer 46

sugar; mesophyll; water; osmosis

Question 47

T/F: Root activities supporting water transport are all passive, requiring no additional energy.

Answer 47

False

Question 48

Vascular plants store most carbohydrate reserves as:

Answer 48

starch

Question 49

Xylem sap and soil water differ in _____ because of _____.

Answer 49

solute composition; selective uptake by the endodermis

Question 50

why there are abundant air spaces between mesophyll cells in leaves?

Answer 50

because CO2 diffusion is faster in air than in water

Question 51

The structure(s) that allow gases, such as CO2, to diffuse into and out of a leaf are the:

Answer 51

Stomata

Question 52

Photorespiration _____ O2 and _____ CO2.

Answer 52

consumes; releases

Question 53

In vascular plants, water transport works only if:

Answer 53

the water column is continuous between leaves and soil.

Question 54

Why may young leaves that are just emerging from the bud be considered sinks for phloem transport?

Answer 54

They consume more carbohydrates than they produce.

Question 55

Why do plants need an endodermis in their roots?

Answer 55

to provide selectivity of ions entering the xylem

Question 56

Vascular plants hydrate photosynthetic cells using _____, whereas bryophytes do so using _____.

Answer 56

soil water; surface water

Question 57

How do bryophytes avoid damage to their tissues from a dry environment?

Answer 57

Their membranes and macromolecules are able to withstand desiccation and rehydration of the cells without damage.

Question 58

Water flows from vessel to vessel through pits, which are:

Answer 58

primary cell walls that separated the neighboring cells as they grew.

Question 59

Xylem transports _____, whereas phloem transports _____.

Answer 59

water; sugars

Question 60

In the early 20th century, an experiment was conducted to determine how large the forces are that allow leaves to pull water from the soil. The rate at which water flowed from a reservoir into the cut tip of an actively transpiring plant was _____ the flow rate through the branch tip when it was subsequently attached to a vacuum pump.

Answer 60

greater than

Question 61

Water is transported from the soil to the leaves in the:

Answer 61

xylem