AP Biology : Plant Form and Function Flashcards

phloem
Terms Definitions
Abiotic
Nonliving.
Morphology
the external form
Herbaceous
Referring to nonwoody plants.
Nitrogen-Fixing Bacteria
Microorganisms that restock nitrogenous minerals in the soil by converting nitrogen to ammonia.
Mycorrhizae
Mutualistic associations of plant roots and fungi.
Xylem
Vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from roots to the rest of the plant.
Etiolation
Plant morphological adaptations for growing in darkness.
Stamen
The pollen-producing male reproductive organ of a flower, consisting of an anther and filament.
Photoperiodism
A physiological response to photoperiod, the relative lengths of night and day. An example is flowering.
phototropin
A blue-light photoreceptor that mediates phototropism
Phytoalexin
An antibiotic, produced by plants, that destroys microorganisms or inhibits their growth.
Sustainable Agriculture
Long-term productive farming methods that are environmentally safe.
Humus
Decomposing organic material found in topsoil.
Sclereid
A short, irregular sclerenchyma cell in nutshells and seed coats and scattered through the parenchyma of some plants.
Tracheid
A long, tapered water-conducting cell that is dead at maturity and is found in the xylem of all vascular plants.
Second Messenger
A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cells interior in response to a signal received by a signal receptor protein.
Expansins
Plant enzymes that break the cross-links (hydrogen bonds) between cellulose microfibrils and other cell wall constituents, loosening the walls fabric.
Translocation
(1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants.
Fragmentation
A means of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.
Haustorium
In symbiotic fungi, specialized hyphae that can penetrate the tissues of host organisms.
Phloem
Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant.
Spongy Mesophyll
Loosely arranged photosynthetic cells located below the palisade mesophyll cells in a leaf.
Guttation
The exudation of water droplets, caused by root pressure in certain plants.
cryptochromes
pigment used to detect blue light
Photomorphogenesis
Effects of light on plant morphology.
Plasticity
An organism's ability to alter or molditself in response to local environmental conditions.
Osmosis
The diffusion of water across a selectively permeable membrane.
Primary Growth
Growth produced by apical meristems, which lengthen stems and roots.
Meristem
Plant tissue that remains embryonic as long as the plant lives, allowing for indeterminate growth.
Megaspore
A spore from a heterosporous plant species that develops into a female gametophyte.
Macronutrient
A chemical substance that an organism must obtain in relatively large amounts. See also micronutrient.
Ethylene
The only gaseous plant hormone. Among its many effects are response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening.
Ovule
A structure that develops within the ovary of a seed plant and contains the female gametophyte.
Epicotyl
In an angiosperm embryo, the embryonic axis above the point of attachment of the cotyledon(s).
Topsoil
A mixture of particles derived from rock, living organisms, and humus.
Transgenic
Pertaining to an individual plant or animal whose genome contains a gene introduced from another organism, either from the same or a different species.
Tonoplast
A membrane that encloses the central vacuole in a plant cell, separating the cytosol from the vacuolar contents, called cell sap; also known as the vacuolar membrane.
Carpel
The female reproductive organ of a flower, consisting of the stigma, style, and ovary.
Cortex
Ground tissue that is between the vascular tissue and dermal tissue in a root or dicot stem.
Bacteroids
A form of Rhizobium contained within the vesicles formed by the root cells of a root nodule.
Annuals
A flowering plant that completes its entire life cycle in a single year or growing season.
Anther
In an angiosperm, the terminal pollen sac of a stamen, where pollen grains with male gametes form.
Aquaporin
A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis).
Vascular Cylinder
The central cylinder of vascular tissue in a root.
Stock
The plant that provides the root system when making a graft.
Sapwood
Outer layers of secondary xylem that still transport xylem sap.
Endosperm
A nutrient-rich tissue formed by the union of a sperm cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds.
Scutellum
A specialized type of cotyledon found in the grass family.
Sepal
A modified leaf in angiosperms that helps enclose and protect a flower bud before it opens.
Gibberellins
promote seed and bud germination, stem elongation, and leaf growth; stimulate flowering and development of fruit; affect root growth and differentiation
Palisade Mesophyll
One or more layers of elongated photosynthetic cells on the upper part of a leaf; also called palisade parenchyma.
Vascular Cambium
A cylinder of meristematic tissue in woody plants that adds layers of secondary vascular tissue called secondary xylem (wood) and secondary phloem.
Phytochromes
A class of light receptors in plants. Mostly absorbing red light, these photoreceptors regulate many plant responses, including seed germination and shade avoidance.
Tropism
A growth response that results in the curvature of whole plant organs toward or away from stimuli owing to differential rates of cell elongation.
Petal
A modified leaf of a flowering plant. Petals are the often colorful parts of a flower that advertise it to insects and other pollinators.
PR Protein
A protein involved in plant responses to pathogens (PR = pathogenesis-related).
Transpiration
The evaporative loss of water from a plant.
Stigma
The sticky part of a flower's carpel, which traps pollen grains.
Flaccid
Limp. A walled cell is flaccid in surroundings where there is no tendency for water to enter.
Endodermis
The innermost layer of the cortex in plant roots; a cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder.
Gene-for-Gene Recognition
A widespread form of plant disease resistance involving recognition of pathogen-derived molecules by the protein products of specific plant disease resistance genes.
Cuticle
A waxy covering on the surface of stems and leaves that acts as an adaptation to prevent desiccation in terrestrial plants.
Cation Exchange
A process in which positively charged minerals are made available to a plant when hydrogen ions in the soil displace mineral ions from the clay particles.
Cytokinins
A class of related plant hormones that retard aging and act in concert with auxin to stimulate cell division, influence the pathway of differentiation, and control apical dominance.
De-etiolation
The changes a plant shoot undergoes in response to sunlight; also known informally as greening.
Dioecious
A term typically used to describe an angiosperm species in which carpellate and staminate flowers are on separate plants.
Determinate Growth
A type of growth characteristic of most animals and some plant organs, in which growth stops after a certain size is reached.
Dermal Tissue System
The outer protective covering of plants.
Adventitious
A term describing any plant organ that grows in an atypical location, such as roots growing from stems.
Apoptosis
The changes that occur within a cell as it undergoes programmed cell death, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die.
Action Potential
A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels.
Action Spectrum
A graph that depicts the relative effectiveness of different wavelengths of radiation in driving a particular process.
Avirulent
A term describing a pathogen that can only mildly harm, but not kill, the host plant.
Turgor Pressure
The force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis.
Blue-Light Photoreceoptos
A class of light receptors in plants. Blue light initiates a variety of responses, such as phototropism and slowing of hypocotyl elongation.
Apical Meristem
Embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length.
Vernalization
The use of cold treatment to induce a plant to flower.
Seed Coat
A tough outer covering of a seed, formed from the outer coat of an ovule. In a flowering plant, the seed coat encloses and protects the embryo and endosperm.
Phototropism
Growth of a plant shoot toward or away from light.
Abscisic Acid (ABA)
A plant hormone that slows down growth, often antagonizing actions of growth hormones. Two of its many effects are to promote seed dormancy and facilitate drought tolerance.
Ovary
In flowers, the portion of a carpel in which the egg-containing ovules develop.
Megapascal (MPa)
A unit of pressure equivalent to 10 atmospheres of pressure.
Long-Day Plant
A plant that flowers (usually in late spring or early summer) only when the light period is longer than a critical length.
Loam
The most fertile of all soils, made up of roughly equal amounts of sand, silt, and clay.
Petioles
The stalk of a leaf, which joins the leaf to a node of the stem.
Guard Cells
The two cells that flank the stomatal pore and regulate the opening and closing of the pore.
Short-Day Plant
A plant that flowers (usually in late summer, fall, or winter) only when the light period is shorter than a critical length.
Shoot System
the aerial portion of a plants body including the stem, the leaves, and (in angiosperms) the flower
Salicylic Acid
A plant hormone that may be partially responsible for activating systemic acquired resistance to pathogens.
Sieve-Tube member
A living cell that conducts sugars and other organic nutrients in the phloem of angiosperms. They form chains called sieve tubes.
Triple Response
A plant growth maneuver in response to mechanical stress, involving 3 steps: slowing of stem elongation, a thickening of the stem, and a curvature that causes the stem to start growing horizontally.
Root Pressure
The upward push of xylem sap in the vascular tissue of roots.
Companion Cell
A type of plant cell that is connected to a sieve-tube member by many plasmodesmata and whose nucleus and ribosomes may serve one or more adjacent sieve-tube members.
Zone of Maturation
The zone of primary growth in roots where cells complete their differentiation and become functionally mature.
Root System
All of the plants roots that anchor it in the soil, absorb and transport minerals and water, and store food
Sugar Sink
A plant organ that is a net consumer or storer of sugar. Growing roots, shoot tips, stems, and fruits are sugar sinks supplied by phloem.
Sugar Source
A plant organ in which sugar is being produced by either photosynthesis or the breakdown of starch. Mature leaves are the primary sugar sources of plants.
Systemic Acquired Resistance (SAR)
Pathogen attack in a localized region of a plant can lead to release of alarm signals to uninfected areas of the plant, providing what is most accurately referred to as ________?
Zone of Cell Division
The zone of primary growth in roots consisting of the root apical meristem and its derivatives. New root cells are produced in this region.
Lateral Roots
branch roots
Vessels
Continuous water-conducting micropipes found in most angiosperms and a few nonflowering vascular plants.
Phytoremediation
An emerging nondestructive technology that seeks to cheaply reclaim contaminated areas by taking advantage of the remarkable ability of some plant species to extract heavy metals and other pollutants from the soil and to concentrate them in easily harvested portions of the plant.
Apomixis
The asexual production of seeds.
Chemiosmosis
An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cells occurs by chemiosmosis.
Heartwood
Older layers of secondary xylem, closer to the center of a stem or root, that no longer transport xylem sap.
Callus
A mass of dividing, undifferentiated cells at the cut end of a shoot.
Nitrogen Fixation
The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants.
Polarity
A lack of symmetry. Structural differences in opposite ends of an organism or structure, such as the root end and shoot end of a plant.
Leaf Primordia
Fingerlike projections along the flanks of a shoot apical meristem, from which leaves arise.
Radicle
An embryonic root of a plant.
zeaxanthin
A carotenoid based photoreceptor that causes stomata to open or close
chromophore
light absorbing part of a molecule
Fusiform initials
Cells within the vascular cambrium that produce elongated cells such as trocheids, vessel elements, fibers, and sieve-tube members.
Oligosaccharin
A type of elicitor (molecule that induces a broad defense response in plants) that is derived from cellulose fragments released by cell wall damage.
Hypocotyl
In an angiosperm embryo, the embryonic axis below the point of attachment of the cotyledon(s) and above the radicle.
Pericycle
The outermost layer of the vascular cylinder of a root, where lateral roots originate.
Perennials
flowering plants that live for more than two years
Mineral Nutrient
An essential chemical element absorbed from the soil in the form of inorganic ions.
Periderm
The protective coat that replaces the epidermis in plants during secondary growth, formed of the cork and cork cambium.
Inflorescence
A group of flower tightly clustered together.
Parenchyma Cell
A relatively unspecialized plant cell type that carries out most of the metabolism, synthesizes and stores organic products, and develops into a more differentiated cell type.
Nitrogenase
An enzyme complex, unique to certain prokaryotes, that reduces N2 to NH3.
Initials
Cells that remain within an apical meristem as sources of new cells.
Morphogenesis
The development of body shape and organization.
ABC Model
A model of flower formation identifying three classes of organ identity genes that direct formation of the four types of floral organs.
Statolith
In plants, a specialized plastid that contains dense starch grains and may play a role in detecting gravity; in invertebrates, a grain or other dense granule that settles in response to gravity and is found in sensory organs that function in equilibrium.
Thigmomorphogenesis
A response in plants to chronic mechanical stimulation, resulting from increased ethylene production. An example is thickening stems in response to strong winds.
Biennials
A flowering plant that requires two years to complete its life cycle.
Virulent
A term describing a pathogen against which a plant has little specific defense.
Water Potential
The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure.
Auxin
A term that primarily refers to indoleacetic acid (IAA), a natural plant hormone that has a variety of effects, including cell elongation, root formation, secondary growth, and fruit growth.
Crop Rotation
The alternation of planting a nonlegume one year and a legume the next year to restore concentration of fixed nitrogen in the soil.
Double Fertilization
A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm.
Ray initials
Cells within the vascular cambrium that produce xylem and phloem rays, radial files that consist mostly of parenchyma cells.
Greening
The elongation rate of the stems slows, the leaves expand, the roots start to elongate, and the entire shoot begins to produce chlorophyll.
Heat-Shock Protein
a folding accessory protein; ensures that proteins do not de-nature at high temperatures
Vascular Bundle
A strand of vascular tissues (both xylem and phloem) in a stem or leaf.
Vacuolar Membrane
A membrane that encloses the central vacuole in a plant cell, separating the cytosal from the vacuolar contents, called cell sap; also known as the tonoplast.
Protoplast
The contents of a plant cell exclusive of the cell wall.
Organ Identity Genes
Plant homeotic genes that use positional information to determine which emerging leaves develop into which types of floral organs.
Protoplast Fusion
The fusing of two protoplasts from different plant species that would otherwise be reproductively incompatible.
Primary Plant Body
The tissues produced by apical meristems, which lengthen stems and roots.
Pattern Formation
The ordering of cells into specific three-dimensional structures, an essential part of shaping an organism and its individual parts during development.
Thigmotropism
A directional growth of a plant in response to touch.
Scion
The twig grafted onto the stock when making a graft.
Pressure Potential
A component of water potential that consists of the physical pressure on a solution, which can be positive, zero, or negative.
Pit
A thinner region in the walls of tracheids and vessels where only primary wall is present.
Stele
The vascular tissue of a stem or root.
Style
The stalk of a flower's carpel, with the ovary at the base and the stigma at the top.
Transport Protein
A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.
Sclerenchyma Cell
A rigid, supportive plant cell type usually lacking protoplasts and possessing thick secondary walls strengthened by lignin at maturity.
Multiple Fruit
A fruit derived from an inflorescence, a group of flowers tightly clustered together.
Brassinosteroids
Steroid hormones in plants that have a variety of effects, including cell elongation, retarding leaf abscission, and promoting xylem differentiation.
Horizon
A distinct layer of soil, such as topsoil.
Ground Tissue System
Plant tissues that are neither vascular nor dermal, fulfilling a variety of functions, such as storage, photosynthesis, and support.
Elicitor
A molecule that induces a broad type of host defense response.
Circadian Rhythm
A physiological cycle of about 24 hours that is present in all eukaryotic organisms and that persists even in the absence of external cues.
Cork Cambium
A cylinder of meristematic tissue in woody plants that replaces the epidermis with thicker, tougher cork cells.
Asexual Reproduction
A type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more parts.
Membrane Potential
The charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.
Micronutrient
An element that an organism needs in very small amounts and that functions as a component or cofactor of enzymes. See also macronutrient.
Leaf Trace
A small vascular bundle that extends from the vascular tissue of the stem through the petiole and into a leaf.
Angiosperm
a plant that produces seeds that are enclosed in a protective structure
Lenticels
Small raised areas in the bark of stems and roots that enable gas exchange between living cells and the outside air.
Monoecious
A term typically used to describe an angiosperm species in which carpellate and staminate flowers are on the same plant.
Apoplast
In plants, the continuum of cell walls plus the extracellular spaces.
Jasmonic Acid
An important molecule in plant defense against herbivores.
Indeterminate Growth
A type of growth characteristic of plants, in which the organism continues to grow as long as it lives.
Thigmotrophism
A directional growth of a plant in response to touch.
Trophism
A growth response that results in the curvature of whole plant organs toward or away from stimuli owing to differential rates of cell elongation.
Day-Neutral Plant
A plant whose flowering is not affected by photoperiod.
Coleoptile
The covering of the young shoot of the embryo of a grass seed.
Coleorhiza
The covering of the young root of the embryo of a grass seed.
Collenchyma Cell
A flexible plant cell type that occurs in strands or cylinders that support young parts of the plant without restraining growth.
Bulk Flow
The movement of water due to a difference in pressure between two locations.
Active Transport
The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins.
Wilting
The drooping of leaves and stems as a result of plant cells becoming flaccid.
Tissue System
One or more tissues organized into a functional unit connecting the organs of a plant.
Aggregate Fruit
A fruit derived from a single flower that has more than one carpel.
Plasmolyze
To shrink and pull away from a cell wall, or when a plant cell protoplast pulls away from the cell wall as a result of water loss.
Solute Potential
A component of water potential that is proportional to the number of dissolved solute molecules in a solution and measures the effect of solutes on the direction of water movement; also called osmotic potential, it can be either zero or negative.
Essential Element
In plants, a chemical element that is required for the plant to grow from a seed and complete the life cycle, producing another generation of seeds.
Fibrous Root System
A root system common to monocots consisting of a mat of thin roots spreading out below the soil surface.
Lateral Meristem
A meristem that thickens the roots and shoots of woody plants. The vascular cambium and cork cambium are lateral meristems.
Secondary Plant Body
The tissues produced by the vascular cambium and cork cambium, which thicken the stems and roots of woody plants.
Root Hair
A tiny extension of a root epidermal cell, growing just behind the root tip and increasing surface area for absorption of water and minerals.
Simple Fruit
A fruit derived from a single carpel or several fused carpels.
Blue-Light Photoreceptors
A class of light receptors in plants. Blue light initiates a variety of responses, such as phototropism and slowing of hypocotyl elongation.
Nodes
A point along the stem of the plant at which leaves are attached.
Zone of Elongation
The zone of primary growth in roots where new cells elongate, sometimes up to ten times their original length.
Vascular Tissue System
A system formed by xylem and phloem throughout a vascular plant, serving as a transport system for water and nutrients, respectively.
Hypersensitive Response (HR)
rapid and localized cell death at the site of infection in resistant interactions between plants and pathogens
Incomplete Flower
A flower in which one or more of the four basic floral organs (sepals, petals, stamens, or carpels) are either absent or nonfunctional.
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