AP Biology Second Semester Final!: Part II (植物 Plants) Flashcards

Terms Definitions
gametophyte formation in male plant organs
microsporangia in microsporphylss produce microspores that develop into pollen grains, which contain the male gametophytes of seed plants
thickened wall of fruit after pollination
pollen grains
contain male gametophytes of seed plants, protected by polymer sporopollenin; male gametophyte develops into pollen tube that discharges sperm
transfer of pollen to the part of a seed plant containing the ovules
pollen tube
after a pollen grain GERMINATES (begins growing); discharges two sperm into female gametophyte w/in ovule
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.
seed coat
structure that surrounds and protects a plant embryo and keeps it from drying out; develops from outer covering of ovule
an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life
becomes the young shoot; below epicotyl and plumule
(anatomy) a small structure resembling a rootlet (such as a fibril of a nerve)
the portion of the stem of a plant embryo that is between the cotyledons and the first true leaves; develops into leaves
a sheath that surrounds and protects apical meristem and primary leaves as they move thru the soil
simple, aggregate, multiple fruit
ripened ovary; fleshy or dry; seed dispersal
primary walls relatively thin and flexible;least specialized, most metabolic functions (organic products)
grouped in strands or cylinders; support young parts of plant shoot; thicker primary walls; young stems and petioles; lack secondary walls; lignin absent in primary walls; flexible support
support; thick secondary walls with lignin; rigid; dead at functional maturity; two types: sclereids and fibers
vascular bundles
stele of stems and leaves divided into; strands consisting of xylem and phloem; phloem found outside, xylem cells inside
determinate growth
A type of growth characteristic of most animals and some plant organs, in which growth stops after a certain size is reached.
indeterminate growth
A type of growth characteristic of plants, in which the organism continues to grow as long as it lives.
meristem tissue
pereptually embryonic tissues;
-made from cells that are undifferentiated (=cells that can become any sort of cell. Ex: blood cells, nervous system cells, etc.)
-used for plant growth and repair
-2 types: apical, lateral
primary plant growth
growth in this region (apical meristem) leads to an increase in the length of a plant; produces primary plant body (parts of root and shoot systems produced by apical meristems)
secondary plant growth
growth that leads to an increase in the width of a plant
apical meristem
-cell divisions allow the plant to get taller (primary growth), but can also cause growth of leaves, branches, and flowers
-located at the tip of each growing stem and root of a plant
lateral meristem
-allows the plant to get wider (secondary growth), thus expanding the width of the plant
-2 types:
1) vascular cambium (=protects vascular tissues and increases the thickness of stems over time. Divisions give rise to new layers of xylem and phloem)
2) cork cambium (=produces outer covering of stems over time)
root cap
covers root tip; protects delicate apical meristem as root pushes through soil during primary growth; secretes polysaccharide slime lubricates soil around root tip
zone of cell division
successive stage of primary growth (no sharp boundaries); includes root apical meristem and derivatives
elongation zone
differentiation zone
root hairs
extensions of epidermal cells; accounts for surface area roots; have hydrophilic walls
palisade mesophyll
spongy mesophyll
have hydrophilic walls
continuum of cell walls plus extracellular spaces
only opening through integument; allows entry of pollen grain
multicellular structure much more resistnat and complex (than a spore); protective coat derived from integument(s) of ovule; may remain dormant; consits of embryo, food supply, packaged w/in protective coat from integuments
where microsporangia develop
generative cell (of pollen grain)
divides to form two sperm from pollen grain; haploid
tube cell (of pollen tube)
produces a pollen tube; haploid
embryo sac
female gametophyte in ovule; consits of antipodal cells, polar nuclei, synergids, and egg
veins netlike; vascular tissue usu. arranged in ring; taproot (MAIN ROOT); pollen green 3 openings; floral organs 4x or 5x; "true" dicots; two cotyledons ; 2/3 of angiosperms
species with one cotyledon; veins usu. parallel; vascular tissue scattered; fibrous root system (W/o main root); pollen grain w/ one opening; floral organs 3x
vascular tissue system
long-distance transport of materials between roots and shoots; xylem and phloem
dermal tissue system
outer protective covering; first line of defense; nonwoody: epidermis; woody: periderm; root hairs are extensions of epidermal cells near root tips
waxy coating in epidermis of leaves and most cells; prevents water loss
leaf trichomes
outgrowths of epidermis; specialization; may secrete oils
vascular cylinder
in angiosperms, stele of root; solid central form
vascular tissue of a root or stem
ground tissue system
tissues not dermal or vascular; pith and cortex; storage, photosynthesis, support
ground tissue internal to vascular tissue; stem tissue; storage
ground tissue external to vascular tissue
cell contents exclusive of cell wall
cotyledons (seed leaves)
store food for developing embryo
nutrient-rich structure formed when a sperm nucleus fuses with two polar nuclei; provides nourishment for developing embryo; in dicots, cotyledon absorbs endosperm
thick, lignified secondary walls; type of sclerenchyma cell
arranged in threads; long, slender, tapered; type of sclerenchyma cell
tracheids and vessel elements
tubular, elongated cells; dead @ functional maturity; nonliving conduit through water can flow; secondary walls interrupted by pits
thinner regions where only primary walls are present; water migrate laterally between neighboring cells through these
tapered ends, through pits; lignin
vessel elements
wider, shorter, thinner walled, less tapered, aligned end to end, end walls have perforations
sugar-conducting cells
alive at functional maturity
sugar-conducting cells in seedless vascular plants and gymnosperms
sugars and other organic nutrients transported through narrow sieve cells
sugar-conducting cells in angiosperms
sieve tubes
sieve-tube members
alive; lack organelles
sieve plates
end walls between sieve-tube members; have pores that facilitate flow of fluid
companion cell
nonconducting cell alongside each sieve-tube member; connected to sieve-tube member by plasmodesmata; organelles of companion cell serve adjacent sieve-tube member ; may help transport sugars
cells that remain as sources of new cells
new cells displaced from meristem; continue to divide until cells produced specialize w/in tissues
lateral transport
short-distance transport; usual direction along radial axis of plant orgnas (not up and down); way water and solutes move within plant tissues and organs; three routes: cell-cell (across membranes), symplast (contiuum of cytosol, plasmodesmata); apoplast (cell walls, extracellular spaces NOT THE PROTOPLAST)
cytoplasmic continuum; plasmodesmata connect cytosolic compartments of neighboring cells to form a continuous pathway
water moves...
from higher to lower water potential
water potential (psi)
determines direction of movement of water; effects of solute concentration and physical pressure (measured by solute and pressure potential); capacity to perform work; measured in megapascals (MPa); pure water = 0 MPa
adding solutes
lowers the water potential
turgor pressure
the pressure that is exerted on the inside of cell walls and that is caused by the movement of water into the cell
transport routes between cells
transmembrane route; apoplastic route; symplastic route
vacuolar membrane (tonoplast)
regulates molecular traffic between the cytosol and the vacuolar contents; proton pumps expel H+ from cytosol into vacuole --> pH gradient
cell sap
vacuolar contents
bulk flow
movement of a fluid driven by pressure
loading of sugar generates
a higher positive pressure at one end of a seive tube; forces sap to opposite end
negative pressure (tension)
drives long-distance transport of xylem
evaporation of water from a leaf, reduces pressure in the leaf xylem --> tension that pulls xylem sap upward from the roots
active transport of sugar
maintains pressure difference (--> bulk flow) mechanism of long-distance transport of phloem sap
exudation of water droplets (seen in morning); not dew (condensed moisture produced during transpiration); caused by root pressure
root pressure
upward push of xylem sap; caused by an accumulation of minerals (at night when transpiration is low) from the structure of the endodermis which prevents ions from leaking out and lowering water potential within vascular cylinder
transpiration(al pull)
loss of water vapor; cause for negative pressure and pulls water from xylem
Casparian strip
belt made of suberin in the transverse and radial walls of each endodermal cell; blocks minerals in apoplast; water and minerals cannot cross endodermis and enter vasc. tissue through apoplast and forcing water and minerals to cross plasma membrane of endodermal cell and enter via symplast
waxy material imperviosu to water and dissolved minerals
innermost layer of cells in the root cortex; surrounds vascular cylinder and functions as last checkpoint for selective passage of minerals from cortex into vascular tissue
water and minerals transported to rest of plant
must enter xylem of the vascular cylinder
symbiotic structures of plant roots and fungal hyphae (filaments); fungal hyphae provide extensive surface area for absorption of water and minerals
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