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49 Cards in this Set
- Front
- Back
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plant sexual reproduction |
-when male and female haploid gametes unite and create diploid fertilized egg Zygote |
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sporophyte |
-diploid, spore producing body of a plant -embryo -sporophyte growth, one or more of its vegatative shoots undergo changes in structure and function and become floral shoots. which gives rise to single flower or many inflorescence |
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meiosis |
- cells in flowers divide by meiosis giving rise to haploid spores, walled cells that divide by mitosis |
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gametophyte |
-spores mitoitically divide giving rise to haploid gametophyte -produces gametes - male: produce sperm (3) -female produce eggs ( 7 cells) |
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alteration of generations |
- division of life cycle into a diploid, spore producing generation and a haploid, gametes producing one |
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chemical signals |
-stimulate flowering - day light and temp, travel to apical meristems of a shoot and trigger changes in cell activity -shoot stops vegative growth and transforms into floral shoot |
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receptacle |
-where flower develops, at end of floral shoot 4 types of concentric tissue called whorls 1. the calyx: is made up of sepals and encloses all other flower parts 2. corolla- includes petals, showy parts 3. two inner whorls- specialized for making gametes |
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corolla |
-inside these petals is whorl of stamens: in which pollen grains (male gametophytes) form stamens consists of slender filament and anther -each anther contains 4 pollen sacs |
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innermost whorl |
- formation and fertilization of eggs -called pistil, include carpels: where female gamteophytes form -lower part is ovary -inside is one or more ovules -tip of style is stigma, which serves as landing platform for pollen |
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complete flowers |
-have all four whorls |
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incomplete flowers |
lack one of more whorls |
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perfect flowers |
-most angiosperms -have both kinds of sexual parts, both stamens and carpels |
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imperfect flowers |
-have stamen or carpels |
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monoecious |
-each plant has some male flowers with only stamens and some female flowers with only carpels |
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dioecious |
- a given plant produces flowers of only one sec |
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microspores |
-give rise to male gametophytes produced in flower bud anthers -the pollen sacs in each anther hold, diploid microsporoctyes -each microsporocyte undergoes meiosis and produces small haploid microspores -microspore divides again by mitosis producing tube cell and generative cell known as pollen grain |
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pollen grain |
tube cell and generative cell -an immature haploid make gametophyte |
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generative cell |
-as part of pollen grain, divides by mitosis forming two sperm cells -this is with tube cell of other pollen grain component, |
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tube cell |
-controls elongating cellular expansion called a pollen tube -the pollen tube grows when pollen grain lands on stigma. -this tube carries the sperm to the ovary |
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pollen grains |
-hardened by decaying resistant polymer sporopllenin, protecting pollen grain through journey from anter to stigma |
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micropyle |
small opening of one end of ovule -where sperm, pollen tube enter |
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ovule |
-inside, a diploid megasporochyte divides by meiosis, forming 4 haploid megaspores - three of the megaspores disintegrate and remaining forms the female gametophyte (haploid) |
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megaspore |
-the remaining megaspore undergoes mitosis without cytoplasmic divdision resulting in a single cell with 8 nuclei arranged in two groups of 4 -one nucleus from each side migrates to center forming polar nuclei -cytoplasma then divides and a cell wall forms around the two polar nuclei, forming endosperm mother cell - a wall forms around other nuclei, three become antipodal cells, which disintegrate -three others at bottom near the micropyle, one is the egg cell and the other two synergids |
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synergids |
have a role in fertilization -result is embryo sac containing 7 cells and 8 nuclei -this embryo sac is the female gametophyte -chemical signals for these two cells lying close to egg help guide the pollen tube towards its destination |
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auxin |
-plant hormone that is a major factoring in determing identities and roles of cells and nuclei within embryo sac -egg cell and synergids develop where auxin is most concentrated, antipodal cells where auxin is the least concentrated -polar nuclei develop where auxin is at intermed concentration |
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pollination |
- process by which plants produce seeds begins with pollination -when pollen grains contact the stigma pollen and stigma have to be compatible |
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self incompatibility |
- prevents self-fertilization - results from interactions between proteins of S (self ) genes S genes- have multiple alleles, and need to be identical for fertilization to occur -prevents inbreeding and promotes genetic variation -it may however preserve adaptive traits in a population |
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double fertilization |
-one sperm nucleus fuses with egg to form diploid (2n) zygote - other sperm fuses with endosperm mother cell, forming triploid (3n) nucleus |
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endosperm |
-tissues derived from 3n cell -nourishes the embryo until it leaves form and photosynthesis has begun - evolution of this embryo nourishment in angiosperms coincided with reduced size of female gametophytes -an angiosperm does not expend energy in filling ovule with food until after the egg has been fertilized |
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zygote |
-when it first forms it starts to develop even before mitosis begins -nucleus and other parts become housed in top half of cell and the vacuole in the lower half -first round of mitosis give rise to a upper apical cell and a lower basal cell |
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basal cell |
form a simple row of cells, the suspensor, which transfers nutrients from the parent plant to the embryo |
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apical cell |
- divisions produce a globe shaped structure attached to the suspensor -Eudicots, become heart shaped, and each lobe in the cotyledon |
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cotyledon |
-provides nutrients for growing tissues in the germinating seed -in some edicts they remain as slender structures and produce enzymes that digest the seeds ample endosperm and transfer the liberated nutrients to the seedling Monocots- one large cotyledon -it absorb the endosperm after germination |
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seed |
- a mature ovule -has protective seed coat -the embryo inside has lengthwise axis with root apical meristem at one end and shoot apical meristem at the other end |
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radicle |
-embryonic root -located near the micropyle, where the pollen tube endured the ovule before fertilization -the radicle attaches to the cotyledon at a region of cells called the hypocotyl -beyond this node is the epicotyl |
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epicotyl |
- has shoot apical meristem at its tip and which bears a cluster of tiny collage leaves the plumule. |
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corn seed |
- a seed is housed inside a kernel -contains a large store of endosperm. -has a single large cotyledon and a shielded shaped mass called a scutellum, which absorbs nutrients from the endosperm |
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monocot embryos |
-protective tissues blanket the root and shoot apical meristems and the shoot apical meristem and plume are covered by a coleoptile: which protects upward growth through soil coleorhiza: sheathes the radical until it breaks out of the seed coat and enters the soil as the young plans primary root |
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fruits |
-angiosperm seeds -fruits provide protection and often seed dispersal -a fruit is a matured ovary - the start of ovule growth marks the end for a flower |
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pericarp |
-ovary wall gives rise to pericarp -a multilayered wall of a fruit -hormones in pollen grains provide initial stimulus that turns on the machinery leading to fruit development. Additional signals come from developing seeds. |
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Fruits |
4 types simpe fruits: develop from single ovary -at least on layer of the fruit wall (pericarp) is fleshy and juicy ex: peaches, tomatoes and taco fruits and nuts and grains Aggregat fruits: formed from several ovaries ex: blackberries and raspberries Multiple fruit: develops from enlarged ovaries of several flowers clustered together in inflorescent ex: pineapple Accessory fruits: floral parts in addition to each ovary become incorporated as the fruit develops ex: pears, apples and strawberries |
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seed germination after dispersal |
- a mature sedd is dehydrated Germination: the onset of the growth of a plant embryo, when seeds begins to soak up water -this happens when external conditions favor the growth of a new sporophyte -once it begins however the embryo loses the protection of the seed coat -it is effected by the soil moisture, oxygen, temperature, day length |
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germination |
1. imbibition: water movies into seed attracted to hydrophilic groups stored in carbs and proteins -seed swells and coat ruptures - radicle begins downward growth, forming the primary root |
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grains |
- seeds endosperm is separated from the pericarp by a thin layer of cells called the aleurone. - as the seed absorbs water, the embryo produces gibberellin, a hormone that stimulated aleurone cells to manufacture and secrete hydropytic enzymes |
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seed dormancy |
- the seeds metabolic activity is suspended -a control system based on hormone ABA underlies the shift from active metabolism to dormancy ABA: stimulates the synthesis of a TF that turns on germination inhibiting genes. It is reversed when regulatory protein binds to TF |
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apomixis |
-asexual plant production - there is no union of haploid maternal and paternal gametes -embryo developes from an unfertilized egg (2n) -the resulting seed contains a somatic embryo, which is identical to parent |
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vegetative reproduction |
- a new genetically identical individual develops from a parents plants nonproductive tissue, usually a bit of meristematic tissue in a bud, root or stem -relys on property of plants, that the fully differentiated plant cells are totipotent- they have the genetic potential to develop into a whole fully functioning plant |
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fragmentation |
-cells in a piece of parent plant can dedifferentiate and then generate missing plant parts |
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vegetative propagation |
- used to grow plants from single cells, using methods of tissue culture -any plant cell that has a nucleus and lacks a secondary cell wall may be totipotent, and develop into a fully functioning plant |
