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
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
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