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active transport: energy-requiring process that moves material across a cell membrane against a concentration difference

angiosperm: flowering plant whose seeds develop inside of ovaries

apical meristem: plant structure containing meristematic tissue that divides, allowing stems and roots to grow in length

autotroph: organism that is able to use a source of energy to produce its food from inorganic raw materials

bulbs: modified stems with most of their food stored in layers of short, thick leaves that wrap around the stem


carpel: structure produced from the fertile leaves that have rolled up to comprise the centermost circle of flower parts

Casparian strip: waterproof strip that surrounds each endodermal cell in a root and is involved in the one-way passage of materials into the vascular cylinder in plant roots

coevolution: process by which two organisms evolve structures and behaivors in response to changes in each other over time

cork cambium: meristematic tissue that produces the outer covering of stems

corms: round underground stems that store food and are surrounded with thin leaves for protection

cotyledon: seed leaf which either carries out the first photosynthesis for the plant, or stores food for the developing embryo

cytoplasm: area between the nucleus and membrane of a cell

dermis: innermost layer of skin beneath the epidermis

dicot: angiosperm whose seed has two cotyledons, and with its vascular bundles in rings, with xylem towards the inside, and phloem towards the outside

dormancy: period during which an organisms growth and activity decrease or stop, usually during unfavorable environmental conditions

embryo: organism at an early stage of development

epidermis: thin layer of root tissue that takes in water and nutrients

fiberous roots: threadlike roots, all of the same size, originating from the base of the stem

flowers: reproductive structures in angiosperms

fruit: protective structure formed from an enlarged, thickened ovary wall that contains angiosperm seeds

gamete: specialized reproductive cell involved in sexual reproduction

gametophyte: haploid plant that produces gametes

guard cells: specialized epidermal cells that control the opening and closing of the stomata by responding to changes in water pressure

haploid: description of cells that contain a single set of chromosomes

herbaceous: description of a plant whose stem has little or no woody tissue

meristematic tissue: plant tissue that produces new cells by mitosis

mesophyll: layer of cells that contains chloroplasts and performs most of a plant's photosynthesis

mitosis: process by which the nucleus of a cell is divided into two nuclei, each with the same number and kinds of chromosomes as the parent cell

monocot: angiosperm whose seeds have one cotyledon, and with scattered vascular bundles

osmosis: diffusion of water molecules through a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration

ovary: base of pistil that contains ovules and developing gametophytes

palisade layer: layer of tall, column-shaped mesophyll cells just beneath the epidermal covering of a leaf

pericycle: type of cambium that allows roots to grow thicker and branch

petals: structures located in the second circle of flower parts just inside the sepals

petiole: structure that attaches the leaf blade to the stem

phloem: vascular tissue responsible for the transport of nutrients and the products of photosynthesis throughout the plant

photosynthesis: process in which autotrophs make their own food using CO2, H2O, and the energy in light

See also: Photosynthesis and Respiration

pistil: female reproductive structure in a flower formed from one or more carpels; consits of the ovary, style, and stigma

pollen grain: structure that contains the male gametophyte in seed plants

pollination: transfer of pollen from the anther of a stamen to the stigma of a pistil

respiration: process that involves oxygen and breaks down food molecules to release engery

See also: Photosynthesis and Respiration

rhizome: thick, fleshy creeping stem that grows either on or just beneath the surface of the ground

seed coat: structure that surrounds a plant embryo and protects it and its food supply from drying out

seed dispersal: process of distributing seeds away from the parent plant

selectively permeable: description of a biological membrane that allows some substances to pass through but not others

sepal: structure in the outermost circle of flower parts that encloses a bud before it opens and protects the developing flower

spongy mesophyll: layer of cells in leaves, arranged in a network with spaces betwen them, that connect with the stomata

stamen: male reproductive structure of a flower belonging to the first circle of fertile leaves located just inside of the petals

stigma: upper part of a pistil upon which pollen grains are deposited

stomata: openings in the leaf epidermis through which water vapor and oxygen pass out of the leaf, and carbon dioxide passes into it

style: stalk between the stigma and the ovary in a flower

taproot: primary plant root that grows longer and thicker than other roots

transpiration: evaporation of water from leaves

tuber: modified underground stem swollen with stored food

vascular cambium: meristematic area that produces vascular tissues and increases the thickness of stems over time

vascular tissue: specialized tissue that transports water and the products of photosynthesis throughout a plant; xylem and phloem tissue

vector pollination: pollination by the actions of animals

xylem: vascular tissue that provides support to a plant and conducts water from the roots to all parts of the plant

zygote: fertilized egg cell

Source: Biology, Prentice-Hall Inc., New Jersey, 1991

Brad Mace Page Created: October 9, 1997 Last Updated:October 12, 1997