Biology Unit 3B

Front 1

stomata

Back 1

A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange.

Front 2

lignin

Back 2

A hard material embedded in the cellulose matrix of vascular plant cell walls that functions as an important adaptation for support in the terrestrial species.

Front 3

cuticle

Back 3

(1) A waxy covering on the surface of stems and leaves that acts as an adaptation to prevent desiccation in terrestrial plants. (2) The exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions.

Front 4

gametophyte

Back 4

The multicellular haploid form in organisms undergoing alternation of generations, which mitotically produces haploid gametes that unite and grow into the sporophyte generation.

Front 5

sporophyte

Back 5

The multicellular diploid form in organisms undergoing alternation of generations that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation.

Front 6

vascular tissue

Back 6

Plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body.

Front 7

gymnosperm

Back 7

A vascular plant that bears naked seeds not enclosed in any specialized chambers.

Front 8

angiosperm

Back 8

A flowering plant, which forms seeds inside a protective chamber called an ovary.

Front 9

xylem

Back 9

The tube-shaped, nonliving portion of the vascular system in plants that carries water and minerals from the roots to the rest of the plant.

Front 10

phloem

Back 10

The portion of the vascular system in plants consisting of living cells arranged into elongated tubes thats transport sugar and other organic nutrients throughout the plant.

Front 11

homosporous

Back 11

Referring to plants in which a single type of spore develops into a bisexual gametophyte having both male and female sex organs.

Front 12

heterosporous

Back 12

Referring to plants in which the sporophyte produces two kinds of spores that develop into unisexual gametophytes, either female or male.

Front 13

trachieds

Back 13

A water-conducting and supportive element of xylem composed of long, thing cells with tapered ends and walls hardened with lignin.

Front 14

vessel elements

Back 14

A specialized short, wide cell in angiosperms; arranged end to end, they form continuous tubes for water transport.

Front 15

cotyledons

Back 15

The one (monocot) or two (dicot) seed leaves of an angriosperm embryo.

Front 16

meristem

Back 16

Plant tissue that remains embryonic as long as the plant lives, allowing for indeterminate growth.

Front 17

primary growth

Back 17

Growth initiated by the apical meristems of a plant root or shoot.

Front 18

secondary growth

Back 18

The increase in girth of the stems and roots of many plants, especially woody, perennial dicots.

Front 19

procambium

Back 19

A primary meristem of roots and shoots that forms the vascular tissue.

Front 20

water potential

Back 20

The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure.

Front 21

turgor pressure

Back 21

The force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis.

Front 22

bulk flow

Back 22

The movement of water due to a difference in pressure between two locations.

Front 23

cohesion

Back 23

The binding together of like molecules, often by hydrogen bonds.

Front 24

Casparian strip

Back 24

A water-impermeable ring of wax around endodermal cells in plants that blocks the passive flow of water and solutes into the stele by way of cell walls.

Front 25

phototropism

Back 25

Growth of a plant shoot toward or away from light.

Front 26

gratitropism

Back 26

A response of a plant or animal in relation to gravity.

Front 27

photoperiodism

Back 27

A physiological response to day length, such as flowering in plants.

Front 28

auxin

Back 28

A class of plant hormones, including indoleacetic acid (IAA), having a variety of effects, such as phototropic response through the stimulation of secondary growth, and the development of leaf traces and fruit.

Front 29

cytokinins

Back 29

A class of related plant hormones that reatard aging and act in concert with auxins to stimulate cell division, influence the pathway of differentiation, and control apical dominance.

Front 30

gibberllin

Back 30

A class of related plant hormones that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormacy, and stimulate fruit development with auxin.

Front 31

abscisic acid

Back 31

A plant hormone that generally acts to inhibit growth, promote dormancy, and help the plant tolerate stressful conditions.

Front 32

ethylene

Back 32

The only gaseous plant hormone, responsible for fruit ripening, growth inhibition, leaf abscission, and aging.

Front 33

statoliths

Back 33

Plants may tell up from down by the settling of statoliths, specialized plastids containing dense starch grains, to the low points of cells.

Front 34

circadian rhythm

Back 34

A phsiological cycle of about 24 hours, present in all eukaryotic organisms, that persists even in the absence of external cues.

Front 35

sieve tubes

Back 35

The food-conducting cells of ploem are sieve-tube members. the cells are living at functional maturity, but lack nuclei. Alongside each sieve-tube member is a nucleated companion cell.

Front 36

guard cells

Back 36

Specialized epidermal cells

Front 37

adhesion

Back 37

The clinging of one substance to another.