lab 8 terms Flashcards
gametophyte
the multicellular haploid generation of the plant life cycle
haploid
having only one set of chromosomes; the 1n chromosome number is characteristic of the gametophyte generation
sporophyte
the multicellular diploid generation of the plant life cycle
diploid
having two sets of chromosomes; the 2n chromosome number is characteristic of the sporophyte generation
gamete
the reproductive cell that must fuse with another gamete to continue the life cycle; the female gamete is the egg and the male gamete is the sperm; when sperm and egg fuse, the zygote produced will grow into the sporophyte
spore
a reproductive cell that grows to produce the gametophyte (does not fuse with another reproductive cell)
mitosis
division of the nucleus which produces genetically-identical nuclei, typically accompanied by cytokinesis
meiosis
special type of division that cuts the chromosome number in half; a diploid cell divides by meiosis to produce haploid cells
zygote
a diploid cell produced by fertilization of an egg by a sperm; will divide by mitosis to produce the sporophyte
alternation of generations
a type of life cycle where the organism spends part of its life as a multicellular sporophyte and part of its life as a multicellular gametophyte
homosporous plant
a plant that produces only one type of spore within its life cycle
heterosporous plant
a plant which produces two types of spores within its life cycle: a microspore which grows into a male gametophyte and a megaspore that develops into a female gametophyte
microsporangium (pollen sac)
the male reproductive organ where meiosis occurs to produce haploid microspores; part of the anther of the stamen
microsporocyte
a diploid cell produced within the microsporangium (pollen sac) in the anther of a stamen; will divide by meiosis to produce haploid spores
microspore
a reproductive cell produced by meiosis of a microsporocyte within a microsporangium; will grow by mitosis into a male gametophyte, the pollen grain
endothecium
a layer of parenchyma cells, one cell thick, part of the wall of an anther just underneath the epidermis
middle layer
a ring of small cells around each pollen sac, several cells thick, between the endothecium and the tapetum
tapetum
a ring of large, elongated cells that forms the innermost layer of a pollen sac wall; provides nutrition to the microsporocytes and developing pollen grain
lip cells
elongated, modified epidermal cells at the seams of the anther; puts pressure on the wall of the pollen sac to cause it to open, forming the stomium and releasing the pollen
stomium
the opening of a mature anther through which the pollen will be released
pollen grain (male gametophyte)
the male, multicellular haploid generation of an angiosperm life cycle; produced by mitosis of a microspore within a pollen sac of an anther
sporopollenin
a tough substance that forms the exine (outer wall) of a pollen grain; very resistant to decay
exine
the protective outer coat of a pollen grain; composed of sporopollenin; can be highly sculptured
generative cell
a cell of the two-celled pollen grain; produces the two sperm cells needed for double fertilization
tube (vegetative) cell
a cell of the two-celled pollen grain; produces and directs the growth of the pollen tube which will deliver the sperm to an ovule
sperm
the male gamete of an angiosperm; two are produced to fertilize the egg and the central cell during double fertilization
papillae
extensions from the epidermis of the stigma to capture pollen and facilitate its germination
integuments
the cell layers surrounding the nucellus of an ovule; will mature into the seed coat
micropyle
an opening in the integuments of an ovule through which the pollen tube grows
megasporangium (nucellus)
the inner part of an ovule within which megaspores and the embryo sac are formed
embryo sac (female gametophyte)
the female, multicellular haploid generation of an angiosperm life cycle; produced by mitosis of a megaspore within the nucellus of an ovule
megasporocyte
a diploid cell produced within a megasporangium (nucellus) within the ovule of an ovary; will divide by meiosis to produce haploid megaspores
megaspore
a reproductive cell produced by meiosis of a megasporocyte within a megasporangium; will undergo mitosis to produce a female gametophyte , the embryo sac
antipodal cell
a cell of the female gametophyte (embryo sac) of an angiosperm; there are three antipodal cells at one end of a mature embryo sac
central cell
a large cell of the female gametophyte (embryo sac) of an angiosperm; it is centrally located and contains two polar nuclei and is diploid; will fuse with a sperm cell during double fertilization to produce the triploid primary endosperm cell
polar nuclei
two nuclei of the female gametophyte (embryo sac) of an angiosperm; they migrate from each end of the embryo sac after mitosis of the megaspore and eventually fuse to form the nucleus of the central cell
egg
the female gamete of an angiosperm; a cell of the female gametophyte (embryo sac); will fuse with a sperm cell during double fertilization to form the diploid zygote which will produce the new sporophyte embryo
synergid
a cell of the female gametophyte (embryo sac) of an angiosperm; there are two synergid cells, closely associated with the egg cell, at one end of a mature embryo sac
pollination
the transfer of pollen from the anther to the stigma
pollen tube
a tube formed when a pollen grain germinates on the stigma; produced as an extension of the tube cell of the pollen grain; transports the sperm to an ovule for fertilization
double fertilization
unique to angiosperms; fusion of a sperm and egg to form a diploid zygote and the simultaneous fusion of a sperm and the central wall to form a triploid primary endosperm cell; occurs within the embryo sac of an ovule within the ovary of a pistil
primary endosperm cell
a triploid cell resulting from the fusion of a sperm and the central cell (or the two polar nuclei) during double fertilization; will divide by mitosis to produce the endosperm - the food supply within the angiosperm seed
triploid
having three sets of chromosomes; 3n - because the primary endosperm cell is triploid it can produce the endosperm food supply very rapidly since is has three copies of each gene
embryo
a young, diploid sporophyte plant; the zygote undergoes mitosis within the ovule to produce the embryo as the ovule matures into a seed; the embryo remains dormant within the seed until germination when it grows very rapidly
endosperm
a triploid tissue, containing stored food, that develops from the primary endosperm cell within an ovule; its food is absorbed by the embryo either before or after the maturation of the seed; unique to angiosperms
seed
a fertilized, matured ovule containing the embryo sporophyte; the ovules mature into seeds as the ovary around them matures into a fruit
seed coat (testa)
a out layer of a seed develops from the integuments if the ovule
iodine (IKI)
a chemical used to test for the presence of starch; turns black in the presence of starch
Bradford solution
a solution which changes colour in the presence of protein
