Unit 6 Biology Words

Front 1

pith

Back 1

the soft, spongy central cylinder of parenchymatous tissue in the stems of dicotyledonous plants

Front 2

phloem

Back 2

the part of a vascular bundle consisting of sieve tubes, companion cells, parenchyma, and fibers and forming the food-conducting tissue of a plant.

Front 3

dicots

Back 3

A flowering plant with two embryonic seed leaves or cotyledons that usually appear at germination

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monocots

Back 4

Any of a class of angiosperm plants having a single cotyledon in the seed. Monocotyledons have leaves with parallel veins, flower parts in multiples of three, and fibrous root systems. Their primary vascular bundles are scattered throughout the stem, not arranged in a ring as in eudicotyledons. Grasses, palms, lilies, irises, and orchids are monocotyledons. See more at leaf. Compare eudicotyledon.

Front 5

meristem

Back 5

embryonic tissue in plants; undifferentiated, growing, actively dividing cells

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pericycle

Back 6

the outermost cell layer of the stele in a plant, frequently becoming a multilayered zone.

Front 7

cortex

Back 7

the portion of a stem between the epidermis and the vascular tissue; bark

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tracheids

Back 8

A cell in the xylem of vascular plants

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mesophyll

Back 9

the parenchyma, usually containing chlorophyll, that forms the interior parts of a leaf

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periderm

Back 10

the cork-producing tissue of stems together with the cork layers and other tissues derived from it.

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turgid

Back 11

swollen; distended; tumid.

Front 12

osmosis

Back 12

the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane.

Front 13

tonoplast

Back 13

a membrane separating a vacuole from the surrounding cytoplasm in a plant cell.

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tension

Back 14

the force producing such deformation

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mycorrhizae

Back 15

a symbiotic association of the mycelium of a fungus, esp. a basidiomycete, with the roots of certain plants, in which the hyphae form a closely woven mass around the rootlets or penetrate the cells of the root.

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guttation

Back 16

a process in which water in liquid form is given off by plants.

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cohesion

Back 17

the congenital union of one part with another

Front 18

chemiosmosis

Back 18

A theoretical mechanism (proposed by Mitchell) to explain energy transduction in the mitochondrion. As a general mechanism it is the coupling of one enzyme catalysed reaction to another using the transmembrane flow of an intermediate species. For example Cytochrome oxidase pumps protons across the mitochondrial inner membrane and ATP synthesis is driven by re entry of protons through the ATP synthesising protein complex. The alternative model is production of a chemical intermediate species, but no compound capable of coupling these reactions has ever been identified.

Front 19

plasmolyze

Back 19

To subject to plasmolysis.

Front 20

transpiration

Back 20

the passage of water through a plant from the roots through the vascular system to the atmosphere

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humus

Back 21

the dark organic material in soils, produced by the decomposition of vegetable or animal matter and essential to the fertility of the earth.

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loams

Back 22

A mixture of moist clay and sand, and often straw, used especially in making bricks and foundry molds

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macronutrients

Back 23

An element, such as carbon, hydrogen, oxygen, or nitrogen, required in large proportion for the normal growth and development of a plant.

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micronutrients

Back 24

A substance, such as a vitamin or mineral, that is essential in minute amounts for the proper growth and metabolism of a living organism

Front 25

topsoil

Back 25

the fertile, upper part of the soil.

Front 26

nitrogenase

Back 26

an enzyme complex that catalyzes the reduction of molecular nitrogen in the nitrogen-fixation process of bacteria.

Front 27

nodules

Back 27

A small knoblike outgrowth, as those found on the roots of many leguminous plants

Front 28

bacteroids

Back 28

Any of various structurally modified bacteria, such as those occurring on the root nodules of leguminous plants.

Front 29

mycorrhizae

Back 29

a symbiotic association of the mycelium of a fungus, esp. a basidiomycete, with the roots of certain plants, in which the hyphae form a closely woven mass around the rootlets or penetrate the cells of the root.

Front 30

horizons

Back 30

the line or circle that forms the apparent boundary between earth and sky

Front 31

sporophyte

Back 31

the form of a plant in the alternation of generations that produces asexual spores

Front 32

gametophyte

Back 32

the sexual form of a plant in the alternation of generations.

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monoecious

Back 33

having both male and female organs in the same individual; hermaphroditic

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dioecious

Back 34

having the male and female organs in separate and distinct individuals; having separate sexes.

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microspore

Back 35

the smaller of the two kinds of spores characteristically produced by seed plants and some fern allies, developing into a male gametophyte

Front 36

megaspore

Back 36

the larger of the two kinds of spores characteristically produced by seed plants and a few fern allies, developing into a female gametophyte

Front 37

scutellum

Back 37

the shieldlike cotyledon of certain monocots

Front 38

coleorhiza

Back 38

the sheath that envelops the radicle in certain plants and that is penetrated by the root in germination

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stock

Back 39

supply of goods kept on hand for sale to customers by a merchant, distributor, manufacturer, etc.; inventory

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scion

Back 40

Also, cion. a shoot or twig, esp. one cut for grafting or planting; a cutting

Front 41

auxin

Back 41

a class of substances that in minute amounts regulate or modify the growth of plants, esp. root formation, bud growth, and fruit and leaf drop

Front 42

ethylene

Back 42

containing the ethylene group

Front 43

tropisms

Back 43

an orientation of an organism to an external stimulus, as light, esp. by growth rather than by movement

Front 44

statoliths

Back 44

Crystalline particles of calcium carbonate and a protein adhering to the gelatinous membrane of the maculae of the utricle and saccule.

Front 45

phytoalexins

Back 45

any of a class of plant compounds that accumulate at the site of invading microorganisms and confer resistance to disease.

Front 46

gravitropism

Back 46

oriented growth with respect to the force of gravity.

Front 47

phytochrome

Back 47

a plant pigment that is associated with the absorption of light in the photoperiodic response and that may regulate various types of growth and development

Front 48

senescene

Back 48

A series of changes in the body which are related to increasing mortality with increasing age. Modern views hold that it is essentially a continuing and increasing failure of adaptability to environmental variations. When the range of environments to which the body can adapt is less than the minimum range normally experienced, death results. In the past, many causes of this decreased adaptability have been suggested, but modern theory suggests that it is due ultimately to errors in the replication of DNA in cell division and/or errors in the production of proteins and enzymes by cells. These errors accumulate as a result of mutation in the hereditary material as the individual becomes older.

Front 49

gibberellin

Back 49

any of a class of growth hormones occurring in fungi and plants.

Front 50

cytokinins

Back 50

Any of a class of plant hormones that promote cell division and growth and delay the senescence of leaves