Bacteria- structurally simpler than all other organisms because they lack membrane-bound organelles such as nuclei, mitochondria, and chloroplasts

Prokaryotes- cells lacking membrane-bound organelles

Eukaryotes- organisms which are not prokaryotes; cells typically contain membrane-bound organelles

Heterotrophic- derive energy from organic molecules made by other organisms

Decomposer- organism that feeds on dead organic matter and release nutrients locked in dead tissue

Autotrophic- organisms, typically bacteria, that derive their energy from the photosynthesis or oxidation of inorganic molecules

Fission- asexual reproductive process in which a cell’s DNA replicates and the cell pinches in half without the nuclear and chromosomal events associated with mitosis

Conjugation- reproductive process in which all or part of the genetic material of one bacterium is transferred to another bacterium and a new set of genes is assembled (genetic recombination)

Gram Stain- important technique used to classify bacteria based on the different structural and chemical compositions of bacterial cell walls

Gram Positive- type of bacteria who have a thick cell wall that retains a purple dye (Streptococcus, Micrococcus)

Gram Negative- type of bacteria who have a thin cell wall that does not retain a purple dye (E. coli, Serratia)

Nitrogen Fixation- process by which certain bacteria and cyanobacteria transform atmospheric nitrogen into other nitrogenous compounds that can be used as nutrients by plants

Nodule- site of association between Rhizobium and host roots of plants

Sensitivity Plate- petri dish of solid medium that has been uniformly inoculated on its entire surface with a known bacterium or an unknown sample from an infected patient

Chlorophyll a- pigment found in cyanobacteria

Phycocyanin (blue) & phycoerythrin (red)- accessory pigments found in cyanobacteria

Sheath- jelly-like covering surrounding cyanobacteria

Trichomes- long chains of Oscillatoria cells

Heterocysts- sites where nitrogen fixation occurs in Nostoc

Prokaryotes- cells lack membrane-bound organelles, all bacteria belong to this class, made up of kingdom Archaebacteria, Eubacteria,

Eukaryotes- cells possess membrane, no bacteria in this class

Archaebacteria- distinctive membranes, unusual cell walls, unique metabolic cofactors, can live in an anaerobic environment; Eubacteria and other multicellular organisms believed to be derived from this kingdom

Eubacteria- heterotrophic; have three kinds of cell walls: Coccus, Bacillus, Spirillum; All individual bacteria 1micrometer or less in diameter

Coccus: Spherical

Bacillus: Rod-shaped

Spirillum: Spiral

Gram Stain

Used to classify bacteria based on different structural and chemical compositions of bacterial cell walls

Eukaryotes- organisms composed of cells having membrane-bound nuclei; organisms divided into four kingdoms: Fungi, Animals, Plants, Protista

Fungi- eukaryotic organisms possessing cell walls and which are heterotrophic

Heterotrophic- characteristic of feeding on organic matter produced by other organisms because these types of organisms cannot make their required organic compounds from inorganic substances

Animals- heterotrophic multicellular eukaryotes that lack cell walls and respond rapidly to external stimuli

Plants- autotrophic multicellular eukaryotes that possess cell walls

Autotrophic- having the ability to synthesize all required organic compounds from inorganic substances using external energy; usually sunlight

Protista- oldest and most diverse of the four kingdoms of eukaryotes; include all eukaryotes that lack the distinguishing characteristics of fungi, animals, and plants. Mostly microscopic, unicellular organisms subdivided into three groups: Algae, Protozoans, Slime Molds

Pigments- substances that absorb light

Phycobilins- water-soluble pigments

Chlorophylls- water-insoluble pigments, can be extracted with organic substances such as alcohol and acetone

Carotenoids- water-insoluble pigments, can be extracted with organic substances such as alcohol and acetone

Unicellular- single, unattached cell which may or may not be motile

Filamentous- chain of cells attached end to end

Colonial- group of cells attached to each other in a nonfilamentous manner

Stigma- reddish, light-absorbing spot at the anterior end of a Chlamydomonas cell

Zygote- union of two gametes to form a diploid organism; resting stage of the life cycle

Isogamous- to have identical shape and appearance

Syngamy- pairing and fusion of haploid gametes to form diploid cells

Spores- reproductive cells capable of developing into an adult without fusing with another cell

Conjugation Tube- result when two mating Spirogyra projections fuse together to exchange cellular contents for the zygote

Sporophyte- diploid stage of the life cycle of Cladophora

Gametophyte- haploid stage of the life cycle of Cladophora

Alternation of Generations- phenomenon of alternating haploid and diploid life stages of an organism

Oogamy- reproductive process in Volvox in which motile sperm swim to and fuse with large nonmotile eggs to form a diploid zygote; The zygote enlarges and develops into a thick-walled zygospore, which is released when the parent colony disintegrates. The zygospore then undergoes meiosis to produce haploid cells that subsequently undergo mitosis and become a new colony

Daughter Colonies- new colonies of Volvox which occur as a result of asexual reproduction in Volvox

Fucoxanthin- brown pigment found in brown algae, phylum Phaeophyta

Conceptacles- tips of Fucus branches, contain reproductive structures

Oogonia- female reproductive structure in Fucus

Antheridia- male reproductive structure in Fucus

Alginic Acid- hydrophilic substance produced by brown algae which is used as an emulsifier in dripless paint, ice cream, pudding, mixes, and cosmetics

Diatomaceous Earth- layers of glass walls of diatoms after their deaths

Eyespot- seeing instrument used by Euglena 

Protist Characteristics: microscopic, unicellular organisms that probably share common ancestry with fungi, multicellular plants, and animals

Examples: amoebas, brown alga, kelp, algae, protozoans, slime molds

Environmental Impact: Brown algae are a source of alginic acid (see definition above) agar derived from red algae, diatoms serve as primary link in food chain of oceans

Shared Characteristics of Green Algae and Land Plants
Presence of Chlorophyll a, Chlorophyll b, Starch as carbohydrate storage material, cell walls made of cellulose

Distinguishing features of algae groups

Energy storage products, cell wall, color, cell organization,

Table 19.1

Green Algae: presence of chlorophyll a, chlorophyll b, starch, cell walls made of cellulose.

Unicellular Green Algae: Chlamydomonas

Filamentous Green Algae: Spirogyra, Cladophora

Colonial Green Algae: Volvox

Brown Algae: grow in cool water, obtain their name by presence of a brown pigment known as fucoxanthin, thalli similar to those of land plants

Red Algae: grow in warm marine waters, obtain their name by presence of phycobilins, thallus can be attached or free-floating, filamentous, or parenchymatous

Diatoms: Unicellular algae containing chlorophyll a and c as well as xanthophyll pigments responsible for their golden-brown color, have a hard cell wall made of silicon dioxide

Dinoflagellates: Unicellular; characterized by the bizarre appearance of cellulose plates and by the presence of two flagella located in perpendicular grooves

Euglenoids: Freshwater unicellular algae, plastids contain chlorophylls a and b, cell walls made largely of protein which makes the cell more flexible; motile, have two flagella

Sexual Reproduction in Chlamydomonas

Response to unfavorable environmental conditions

Vegetative cells undergo mitosis to produce gametes

Gametes fuse to form diploid zygote

Zygote surrounds itself with a resistant surface and is called a zygospore

Classification Structure

Phylum Chlorophyta- green algae, Chlamydomonas, Spirogyra, Cladophora, Volvox

Phylum Phaeophyta- brown algae, Kelp, Sargassum, Fucus, Laminaria

Phylum Rhodophyta- red algae, Polysiphonia, Porphyra

Phylum Bacillariophyta- diatoms

Phylum Dinoflagellata- dinoflagellates, Ptychodiscus bruvis, Peridinium, Ceratium,

Pseudopods- movable extensions of cytoplasm used for locomotion and gathering food

Phagocytic- having the characteristic of engulfing food particles and forming a food vacuole surrounded by membrane

Food Vacuole- instrument used to trap food in phagocytosis

Intracellular Digestion- Process of digestion in which enzymes from phagocytosis are secreted into the food vacuole

Contractile Vacuole- vacuole that maintains the cell’s water balance by accumulating and expelling excess water

Flagellum- long extension protruding from protozoans which assists in locomotion

Undulating Membrane- thin, flat surface that can be undulated or waved for locomotion

Cilia- small hairlike extensions protruding from the bodies of protozoans, assist in locomotion

Micronuclei- type of nuclei found in ciliates that divide by mitosis and contain the genetic information of the cell in normally shaped chromosomes

Macronuclei- type of nuclei found in ciliates that are essential for routine cellular functions

Conjugation- sexual means of reproduction in Paramecium in which individuals from two different strains align longitudinally and exchange nuclear material

Plasmodium- mass of brightly colored protoplasm surrounding slime molds; makes individual cells indistinguishable

Sclerotium- hard resistant structure that the plasmodium may result in under unfavorable environmental conditions

Rhizopoda Characteristics

Presence of pseudopods, lack flagella, most reproduce asexually

Organisms/Related Diseases

Trypanosoma- causes Chagas’ disease

Plasmodium- causes malaria

Spores (N)

Gametes

Fertilization

Zygote

Plasmodium (2N)

Environmental Stress

Sporangia (2N)

Meiosis

Spores

Classification Structure

Phylum Rhizopoda- amoebas

Phylum Foraminifera- shelled amoebas

Phylum Zoomastigina- zoomastigotes; trypanosoma

Phylum Ciliophora- Paramecium

Phylum Sporozoa- sporozoans, Plasmodium

Hypha- slender filament of cytoplasm and haploid nuclei enclosed by a cell wall

Septa- crosswalls that separate cytoplasm and one or more nuclei into cells

Coenocytic- multinucleate, having incomplete or no septa

Mycelium- collective term for a cotton-like mass of hyphae constituting an individual organism; it may extensively permeate soil, water, or living tissue

Chitin- component of cell walls in fungi

Extracellular Digestion- process of digestion in which enzymes are secreted by the chitinous cell wall to be absorbed into the mycelium

Heterotrophs- attain food from other organisms

Saprophytes- to obtain nourishment from dead organic matter

Parasites- to obtain nourishment from live organic matter, to feed on living organisms

Haustoria- modified hyphae that are thin extensions of the hyphae that penetrate living cells and absorb nutrients

Spores- haploid vegetative cells, used in mitotic production by fungi

Sporangia- site of mitotic production of spores

Conidiophores- site of mitotic production of spores

Phototaxis- orientation of an organism to light

Budding- method of asexual reproduction; mitosis with an uneven distribution of cytoplasm; common in yeasts

Fragmentation- method of asexual reproduction, breaking of the organism into one or more pieces, each of which can develop into a new individual

Zygospore- resting sexual spore characterizing bread molds

Rhizoids- modified hyphae known as a holdfast

Stolons- modified hyphae known as connecting hyphae

Sporangiophores- modified hyphae, which functions as a reproductive structure

Gametangia- result of hyphae touching during sexual reproduction of Rhizopus; appears as swellings

Ascus- microscopic, sac-shaped reproductive structure characterizing sac fungi

Conidia- spores found in Ascomycetes that function in asexual reproduction

Dikaryotic- having two nuclei

Monokaryotic- having one nuclei

Ascocarp- cup-shaped structure formed by monokaryotic hyphae from each parent during sexual reproduction in Ascomycota

Ascospores- four haploid structures produced after fusion by meiosis during sexual reproduction in Ascomycota

Cap- structure on a mushroom protecting the gills and pileus

Pileus- structure on a mushroom located beneath the cap

Gills- structure on a mushroom located underneath the cap

Basidia- microscopic, club-shaped cells lining the gills; sites of sexual reproduction in club fungi

Monokaryotic Primary Mycelia- result of septa forming between nuclei in the hyphae; has one nucleus in each cell

Dikaryotic Secondary Mycelium- result of monokaryotic primary mycelia from different mating strains fusing together

Basidiospores- haploid structures occurring as a result of meiosis during sexual reproduction in Basidiomycota

Lichen- common, brightly colored organisms in which an ascomycete lives symbiotically with a photosynthetic alga or cyanobacterium

Symbiosis- living in a close and sometimes dependent association

Crustose- one of three forms of lichen, thallus grows close to surface of a hard substrate such as rock or bark; flat and two-dimensional

Foliose- one of three forms of lichen; adheres to substrate but some of thallus peels and folds away from the substrate in small sheets

Fructicose- three-dimensional structures that grow away from the substrate with erect stalks

Characteristic Features

Absorptive heterotrophs, multicellular, have cell walls of chitin, many saprophytes, some parasitic; reproduction can be sexual or asexual

Classification Structure

Phylum Zygomycota- bread molds; Rhizopus

Phylum Ascomycota- sac fungi; Aspergillus, yeasts, some molds, truffles

Phylum Basidiomycota- club fungi; Agaricus campestris, Amanita phalloides, mushrooms, puffballs

Phylum Deuteromycota- Penicillum

Lichens- Fructicose, Crustose, Foliose

Lichens- Growth Forms/Symbiosis

25000 species, common, brightly colored organisms in which an ascomycete lives symbiotically with a photosynthetic alga or cyanobacterium

Symbiosis: living in a close and sometimes dependent association

Antheridia- male sex organs that produce swimming, biflagellate sperm

Archegonia- female sex organs; site where eggs are produced

Zygote- Fertilized egg between the sperm from the antheridia and the egg from the archegonia

Archegonium- site where the zygote divides and matures

Sporophyte- product of the zygote after maturation and division in the archegonium

Gametophyte- site of nutrition for the sporophyte

Chlorenchyma- chloroplast-containing

Gemmae Cups- structures of liverworts which occur on the dorsal surface of some thalli near the midrib and function in asexual reproduction

Gemmae- lens-shaped outgrowths inside the gemmae cups which are splashed out of the cup by falling drops of rain If a gemma lands in an adequate environment, it can produce a new gametophyte plant

Dioecious- to have separate male and female plants

Archegoniophores- specialized stalks on female plants that bear archegonia

Neck- structure on an archegonium

Venter- structure on an archegonium which contains the egg

Egg- reproductive structure of liverworts contained in the venter

Antheridiophores- specialized stalks on male plants that bear antheridia

Foot- structure connecting the nonphotosynthetic sporophyte to the gametophyte

Spores- structures produced by meiosis in the liverwort sporophyte

Capsule- site where spores are produced in the liverwort sporophyte

Stalk- site where the capsule is located, extends downward from the foot

Elaters- elongate cells that help disperse spores by twisting. In humid conditions, the elaters coil, but when it is dry the elaters expand, pushing the spores apart and rupturing the spore case to release the spores

Rosette- name given to the shape of the leaves when expanded out of the male plant in mosses

Moss Flower- synonym for rosette because of its appearance

Splash Cup- synonym for a rosette because of its function (dispersal of sperm by falling raindrops)

Capsules- structures located atop stalks of the moss sporophyte

Seta- structures that extend upward from the moss gametophyte

Foot- structure connecting the sporophyte of mosses to the gametophyte of mosses

Calyptra- covering atop the capsule, upper portion of the archegonium that covers the apex of the capsule. The calyptra falls off when the capsule matures; inside are numerous haploid spores formed by meiosis

Operculum- caplike structure located on the tip of the capsule

Protenema- photosynthetic structure formed when moss spores germinate; resembles a branching, filamentous alga. Leafy moss plants arise from buds located along the protenema

Bryophyte Characteristics:

Green

Have rootlike structures called rhizoids

May have stem and leaf-like parts

Generally do not possess specialized vascular tissues; this characteristic limits bryophytes to moist habitats; Rhizoids neither penetrate soil very far nor absorb many nutrients

Lack of vascular tissues necessitates that their photosynthetic and nonphotosynthetic tissues be close together

Relatively small and inconspicuous

Occur throughout the world in habitats ranging from tropics to Antarctica

24000 species in existence, fix carbon dioxide, degrade rocks to soil, stabilize soil, reduce erosion

Used by humans as a fuel, in production of Scotch whiskey, and as packing materials

Alternation of Generations; gametophyte predominate vegetative phase

Moss Structure vs. Liverwort Structure

Liverwort Structure: leafy; gametophytic thallus grows as a large, flat, photosynthetic structure on the surface of the ground

Moss Structure: gametophyte plants are leafy and usually stand upright; radially symmetrical

Mosses withstand desiccation better than liverworts

Mosses have less specialized habitats than liverworts

Moss Sexual & Asexual Reproduction

Asexual Reproduction by Fragmentation

Sexual Reproduction: Archegonium matures, cells lining neck disintegrate and form canal leading to the egg. Sperm, following a chemical attractant released by the archegonium, swim through this canal to reach the egg.

Classification Structure

Phylum Hepaticophyta- Liverworts; Marchantia

Phylum Bryophyta- Mosses; Polytrichum

Megaphylls- large leaves with several to many veins

Microphylls- small leaves with only one vein

Sporophylls- leaf-like structures of the sporophyte generation that bear spores; may be megaphylls or microphylls

Rhizomes- underground stems by which fern sporophytes are able to grow indefinitely

Fronds- leaf-like projections on ferns

Sori- groups of sporangia which form on the underside of fern fronds

Sporangia- structures which collectively form the sori, protected by the indusium

Indusium- specialized outgrowth of the frond that protects the sporangia

Annulus- thick-walled cells along the back of the helmet-shaped sporangium

Protonema- threadlike structure formed by fern spores in reproduction

Prothallium- independent, heart-shaped structure which is the product of many subsequent cellular divisions in fern reproduction; valentine plant

Fiddlehead- coiled position of the fronds of the growing sporophyte as a result of the fronds breaking through the soil

Homosporous- in fern reproduction, to produce one kind of spore that develops into a single kind of gametophyte that produces both antheridia and archegonia

Heterosporous- in fern reproduction, to produce two kinds of spores: megaspores and microsprores

Megaspores- structure which forms a gametophyte containing only archegonia

Microspores- structure which forms a gametophyte containing only antheridia

Sporophylls- small modified leaves present in sporangia of Lycopodium (club mosses); clustered in strobili that form at tips of branches

Strobili- cones which are the clusters of sporophylls in club mosses

Rhizophores- prop-like axes along the stem of Isoetes which have structural features that are intermediate between stems and roots

Sporangiophores- modified branches upon which sporangia form in scouring rush

Classification Structure

Phylum Pterophyta- Ferns, Salvinia, Azolla

Phylum Lycophyta- Club Mosses, Lycopodium, Selaginella

Phylum Psilophyta- Whisk Ferns, Psilotum, Tmesipteris

Phylum Sphenophyta- Scouring Rush, Equisetum

Characteristics of Seedless Vascular Plants

Vascular system connects true leaves, roots, and stems

Sporophyte dominant phase of life cycle

"Lower" vascular plants

Presence of sporophylls

Nonflowering plants

Vascular system of fluid-conducting xylem and phloem

Structure, Function, Reasoning of Prothallium

Structure- rhizoids and reproductive structures on underside, globe-shaped antheridia form first, followed by archegonia. Zygote develops in the archegonium and is nutritionally dependent on the gametophyte for a short time. Sporophyte becomes leaflike and crushes the prothallium. Fronds break through soil in a coiled position known as a fiddlehead

Function- means of reproduction for fern spores

Cones- scalelike structures which are sites by which exposed seeds are borne (strobili)

Heterosporous- producing two kinds of spores

Microspores- structures occurring in male cones that form male gametophytes

Megaspores- structures occurring in female cones that form female gametophytes

Microsporophylls- sporophylls of male cones

Microsporangium- layer of cells on the surface of each microsporophyll which produces spores

Megasporophylls- sporophylls of female cones

Megasporangia- spore-producing structure located on the upper surface of megasporophylls

Microspore Mother Cells- diploid structures produced by microsporangium

Microspores- product of the meiosis of microspore mother cells, develop into microgametophytes called pollen grains

Pollen Grain- microgametophyte produced by a microspore, consists of four nuclei and a pair of bladder-like wings

Megaspore Mother Cell- diploid structure produced by megasporangium

Megaspore- product of the meiosis of megaspore mother cells, develops into megagametophytes

Megagametophyte- product of the megaspore

Nucellus- tissue of the megasporangium immediately surrounding the megagametophyte

Integuments- surrounding structure of the nucellus

Ovule- product of a megagametophyte and it’s surrounding tissues; contains at least one archegonium with an egg cell

Ovuliferous Scales- structures arranged spirally on mature ovulate cones, at the base are two naked seeds exposed to the environment

Pollination- transfer of pollen to a receptive surface

Classification Structure

Phylum Cycadophyta- cycads, Zamia

Phylum Ginkgophyta- Maidenhair plant, Ginkgo biloba

Phylum Coniferophyta- conifers, Podocarpus, Juniperus, Pinus

Phylum Gnetophyta- very distinctive seed plants, Welwitschia

Gymnosperm/Seed Characteristics

Gymnosperms: plants with exposed seeds borne on scalelike structures called cones, well developed alternation of generations, heterosporous, gametophytes are microscopic and completely dependent upon the large, free-living sporophyte

Seed: allows a small but multicellular sporophyte to remain dormant until conditions are favorable for continued growth, protected by a coat and surrounded by a food supply

Structures of Gametophyte (N)

Microsporesà Microgametophyteà Spermà Syngamyà Sporophyte

Megasporesà Microgametophyteà Eggà Syngamyà Sporophyte

Structures of Sporophyte (2N)

Sporophyte

Megasporangium

Microsporangium

Peduncle- flower stalk

Receptacle- part of the flower stalk that bears the floral organs; located at the base of the flower, usually not large or noticeable

Sepals- lowermost or outermost structures, which are usually leaflike and protect the developing flower; collectively constitute the calyx

Calyx- collective group of sepals

Petals- located inside and usually above the sepals; may be large and pigmented (in insect-pollinated flowers) or absent (in wind-pollinated plants); the petals collectively constitute the corolla

Corolla- collective group of petals

Perianth- combined calyx and corolla

Androecium- male portion of the plant which rises above and inside the petals; consists of stamens, each of which consists of a filament atop which is located an anther; inside the anthers are pollen grains which produce the male gametes

Stamens- structures inside the androecium, each of which consists of a filament

Filament- structure located on each stamen; contains an anther at its top

Anther- structure located atop the filament, inside are pollen grains

Pollen Grain- structures located inside the pollen grain, which produce the male gametes

Gynoecium- female portion of the plant which rises above and inside the androecium; consists of one or more carpels, each made up of an ovary, style, and stigma; the ovary contains ovules that contain the female gametes; during pollination, pollen grains are transferred to the stigma, where they germinate and grow a tube through the style to the ovary

Carpels- structures located inside the gynoecium, each of which is made up of an ovary, style, and stigma

Ovary- structure located on a carpel, contains ovules that contain the female gametes

Style- structure comprising the carpel

Stigma- structure comprising the carpel

Ovule- structure located in the ovary; contains the female gametes

Regular- characteristic describing if a flower has all parts of the perianth similar in size and shape

Radially Symmetrical- characteristic typical of regular flowers, parts of the perianth are arranged like a wheel

Irregular- characteristic describing if a flower has different parts of the perianth different sizes and shapes

Bilaterally Symmetrical- characteristic typical of irregular flowers, the flower has a clearly defined left and right side

Generative Nucleus- structure located in a pollen grain that is usually small, spindleshaped, and off-center

Tube Nucleus- structure located in a pollen grain that is usually larger and more centered than the generative nucleus

Sporophyte- diploid structure of flowering plants which produces haploid spores by meiosis

Gametophyte- product of the haploid spore; produces gametes by mitosis and cellular differentiation

Sporogenesis- process in alternation of generations that involves the production of spores in the sporophyte by meiosis

Microspores- one of two kinds of spores produced by flowering plants

Megaspores- one of two kinds of spores produced by flowering plants

Gametogenesis- production of gametes by gametophytes

Microsporogenesis- production of microspores within microsporangia of a flower’s anthers via meiosis of microspore mother cells

Microsporangia- site of microsporogenesis; located in the flower’s anthers

Microspore Mother Cells- structures which undergo meiosis to allow microsporogenesis in microsporangia

Tube Nucleus- vegetative nucleus located in the haploid nuclei of a mature pollen grain

Generative Nucleus- structure located in the haploid nuclei of a mature pollen grain; replicates to form two sperm nuclei

Sperm Nuclei- structure produced by the generative nucleus; functions in microsporogenesis

Megasporogenesis- production of megaspores; occurs in the sporangia of the flower ovary by meiosis of megaspore mother cells

Megaspore Mother Cells- known as megasporocytes, structure which undergoes meiosis to allow megasporogenesis in the sporangia of the flower ovary

Megagametogenesis- process in which megaspores develop into megagametophytes which produce egg gametes

Megagametophytes- product of megaspores after undergoing megagametogenesis; produce egg gametes

Ovule- product of the megagametophyte and its surrounding tissues

Integuments- two coverings which shield and protect the ovules

Embryo Sac- entire haploid structure of the ovule and its integuments

Egg- structure associated with fertilization in megagametophytes

Synergid Nuclei- structure associated with fertilization in megagametophytes

Antipodal Cells- three structures in the megagametophyte located at the opposite end of the egg/synergid nuclei that typically do not participate in reproduction

Polar Nuclei- two structures located in the center of the megagametophyte after migrating from each pole of the megagametophyte

Double Fertilization- process in which one sperm nucleus fuses with the egg to form the diploid zygote, and the other sperm nucleus fuses with the two polar nuclei; characteristic of all angiosperms

Zygote- structure that divides to form a mass of cells called the embryo

Embryo- product of the zygote; initially consists of a basal cell, a suspensor, and a two-celled proembryo

Basal Cell- structure located in the embryo

Suspensor- column of cells that push the embryo into the endosperm

Endosperm- extensive structure being digested as the embryo is pushed down into by the suspensor

Cotyledons- structures which form the heart-shaped embryo; store digested food from the endosperm

Stem Apical Meristem- structure in the mature embryo that has large, bent cotyledons on either side

Radicle- structure in the mature embryo which is to later form the root; differentiated towards the suspensor

Root Apical Meristem- structure located on the radicle

Root Cap- structure located on the radicle

Hypocotyl- region between the apical meristem and radicle

Epicotyl- region between attachment of the cotyledons and the stem apical meristem; not yet elongated in the mature embryo

Fruit- mature, ripened ovary plus any associated tissues

Dry- characteristic describing fruit in which cracking/splitting is observed at maturity and seeds are released

Fleshy- characteristic describing fruit in which seeds remain in the tissues until germination

Pericarp- outer wall of a fruit

Exocarp- outside of the pericarp

Mesocarp- region located between the exocarp and endocarp in the pericarp

Endocarp- inside of the pericarp

Placental Tissues- structures located within the pericarp

Characteristics of Angiosperms

Range in size from 1mm (Wolffia) to over 100 m tall (Eucalyptus)

Sporophyte large and independent of the microscopic gametophyte

Divided into monocots and dicots

Presence of Flowers

Presence of Fruit

Flower Parts

See definitions

Monocots vs. Dicots

Monocots: one cotyledon per embryo, flower parts in sets of three, parallel venation in leaves, multiple rings of vascular bundles in stem, lacks a true vascular cambium

Dicots: two cotyledons per embryo, flower parts in sets of four or five, reticulate venation in leaves, one ring of vascular bundles or cylinder of vascular tissue in stem, have a true vascular cambium

Micropyle- small opening on the surface of the seed through which the pollen tube grows

Hilum- adjacent, elliptical area at which the ovule attaches to the ovary

Cotyledon- food for the embryo

Embryo with young root and shoot- develops into new sporophyte

Fruit Characteristics

Mature, ripened ovary plus any associated tissues

Contains seeds

Mature fruit much larger than ovary at time of pollination and fertilization, great deal of development occurs while seeds are maturing

Either dry or fleshy

Contains an outer wall called a pericarp

Often includes receptacle of flower

Classification Structure

Radicle- young primary root which emerges from the seed and grows down

Primary Root- structure which emerges from the seed and grows down

Secondary Roots- numerous structures produced by the primary root, collectively forms a root system that absorbs water and minerals, anchors the plant, and stores food

Taproot System- root system that consists of one large main root and smaller secondary roots branching from it

Fibrous Root System- root system in which primary and secondary roots are similar in size

Primary Growth- refers to the growth of all primary tissues

Apical Meristem- structures which induce primary growth in roots and primary tissues

Secondary Growth- refers to growth in girth resulting from nonapical meristems

Epidermis- outer layer of cells

Cortex- structure located inside the epidermis whose cells contain amyloplasts

Amyloplasts- starch-containing plastids located inside cells of the cortex

Endodermis- inner layer of the cortex; regulates water flow to the vascular tissue in the center of the root

Pericycle- structure inside the endodermis which can become meristematic and produce secondary roots

Vascular Cylinder- fluid-conducting cylinder composed of xylem and phloem

Xylem- structure in the vascular cylinder which transports water and minerals

Phloem- structure in the vascular cylinder which transports most organic compounds in the plant

Tracheids- water conducting cells in the xylem of angiosperms; long spindle-shaped cells with thin areas called pits

Vessels- water conducting cells in the xylem of angiosperms

Pits- thin areas in tracheids where the cell walls of adjacent cells overlap

Sieve Cells- conducting cells in phloem

Sieve Tube Members- conducting cells in phloem

Shoot Apical Meristem- dome-shaped structure in the shoot apex not covered by a cap; produces young leaves that attach to the stem at a node

Leaf Primordia- young leaves produced by the shoot apical meristem which attach to the stem at a node

Node- site of attachment by leaf primodia produced by the shoot apical meristem

Auxiliary Bud- site between the young leaf and the stem which forms a branch or flower

Terminal Bud- structure containing the apical meristem at the stem tip that is surrounded by bud scales

Bud Scales- structures surrounding the terminal meristem

Leaf Scars- sites where leaves have been shed; occur at regularly spaced nodes along the length of the stem

Nodes- regularly spaced increments along the length of the stem at which leaf scars are found

Internodes- portions of stem between nodes

Vascular Bundle Scars- sites of vascular bundle scarring, located within the leaf scars

Bud Scale Scars- clusters that indicate the length of yearly growth by measurement of the distance of one cluster to the next

Epidermis- covering of the stem

Cutin- waxy, waterproof substance coating the epidermis

Cortex- site below the epidermis where food is stored

Pith- structure in the center of the stem which stores food

Collenchyma- small, rectangular cells with unevenly thickened cell walls that support elongating regions of the plant

Sclerenchyma Fibers- large, darkly stained, thick-walled fibers which function in support

Dicots- flowering plants with two cotyledons

Cotyledons- seed leaves

Monocot- flowering plant with only one cotyledon

Vascular Cambium- meristematic tissue between the xylem and phloem and each vascular bundle in dicot stems, secondary meristem that produces secondary growth; Cylindrical, produces secondary xylem to its inside and secondary phloem to its outside

Periderm- tissue that replaces ruptured epidermis and functions to minimize water loss; consists of cork cells produced by another secondary meristem called the cork cambium

Cork Cambium- secondary meristem which produces cork cells that comprise the periderm

Lenticles- structures that serve as the sites for gas exchange through peridermal tissues

Blade- major structure that comprises the leaf

Petiole- major structure that comprises the leaf; attaches the leaf blade to the stem

Simple Leaves- leaves that have one blade connected to the petiole

Compound Leaves- leaves that have several leaflets sharing one petiole

Leaflets- leaves that occur on compound leaves, sharing one petiole

Palmate- type of leaflet on a compound leaf which arise from a central area

Pinnate- type of leaflet on a compound leaf which arise in rows across a central midline

Venation- arrangement of veins

Parallel Veins- veins that extend the entire length of a leaf with little or no cross-linking

Pinnately Veined – leaves that have one major vein from which other veins branch

Palmately Veined- leaves that have several main veins with each one having branches

Phyllotaxis- arrangement of leaves on a stem

Opposite Phyllotaxis- refers to two leaves per node located on opposite sides of a stem

Alternate Phyllotaxis- refers to one leaf per node, with leaves appearing first on one side of a stem and then on another

Whorled Phyllotaxis- refers to more than two leaves per node

Stomata- pores in the epidermis surrounded by two guard cells

Palisade Mesophyll- closely packed cells located just below the upper epidermis; contain about 50 chloroplasts per cell

Spongy Mesophyll- cells with numerous intercellular spaces located below the palisade layers

J EddieJ