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291 Cards in this Set

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hydroponic culture
growing plants by bathing them in nutrient solutions that are aerated as opposed to soil; can be used as a method to determine which of the mineral elements are essential nutrients to a plant; a control plant is bathed in a solution of minerals and an experimental plant is bathed in a solution of the minerals minus the one to be tested; if it wilts then the mineral is essential
Name nine macronutrients essential to plants
carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorous, potassium, calcium, magnesium
Why is nitrogen essential to plants?
Component of nucleic acids, proteins, hormones and coenzymes
Why is sulfur essential to plants?
Component of proteins, coenzymes
Why is potassium essential to plants?
Cofactor that functions in protein synthesis; major solute functioning in water balance; operation of stomata
Why is calcium essential to plants?
Important in formation and stability of cell walls and in maintenance of membrane structure and permeability; activates some enzymes; regulates many responses of cells to stimuli
Why is magnesium essential to plants?
Component of chlorophyll; activates many enzymes
eight micronutrients essential to plants
chlorine, iron, boron, manganese, zinc, copper, molybdenum, nickel
Why is chlorine essential to plants?
Required for water-splitting step of photosynthesis; functions in water balance
Why is iron essential to plants?
Component of cytochromes; activates some enzymes
Why is boron essential to plants?
cofactor in chlorophyll synthesis; may be involved in carbohydrate transport and nucleic acid synthesis
Why is manganese essential to plants?
Active in formation of amino acids; activates some enzymes; required for water-splitting step of photosynthesis
Why is zinc essential to plants?
Active in formation of chlorophyll; activates some enzymes
Why is copper essential to plants?
Component of many redox and lignin-biosynthetic enzymes
Why is molybdenum essential to plants?
Essential for nitrogen fixation; cofactor that functions in nitrate reduction
Why is nickel essential to plants?
Cofactor for an enzyme functioning in nitrogen metabolism
chlorosis
the yellowing of leaves caused by an inability to synthesize chlorophyll
What do mineral deficiency symptoms depend on?
The role of the nutrient in the plant and also its mobility within the plant
humus
a residue of partially decayed organic material
topsoil
a mixture of particles derived from rock, living organisms, and humus
horizons
distinct soil layers
loams
the most fertile soils, made up of roughly equal amounts of sand, silt and clay
What does the presence of clay in a soil help to do?
Prevent leaching of mineral nutrients during heavy rain or irrigation because materials bind to it
cation exchange
when plants secrete H+ to displace positively charged minerals so that it can absorb them
phytoremediation
when a plant is able to uptake heavy metals and other pollutants and concentrate them in easily harvest portions of the plant; used to detoxify soils
nitrogenase
an enzyme complex that catalyzes nitrogen fixation
Plants acquire their nitrogen mainly from what form of nitrogen?
Nitrate, created by nitrification
nodules
swellings in a legume’s roots composed of plant cells that contain nitrogen-fixing bacteria
rhizobium
bacteria that fix nitrogen
bacteroids
the form Rhizobium bacteria assume inside a nodule
Why do some root nodules have a reddish color?
Molecules called leghemoglobin inside the nodules act as an oxygen “buffer”
What do legumes secrete to initiate communication with a Rhizobium?
Flavonoids
What do bacteria respond to flavonoids with?
Secreting enzymes that catalyze production of species-specific molecules called Nod factors
chlorophyll
the green pigment located within chloroplasts
mesophyll
the tissue in the interior of the leaf
Where are chloroplasts mainly found?
In the cells of the mesophyll
How many chloroplasts does a typical mesophyll cell have?
30 to 40
thylakoid space/lumen
the space inside a thylakoid
thylakoid
the site of the light reactions
stroma
the site of the Calvin reactions
grana
stacks of thylakoids
Where is the oxygen given off by plants derived from?
water
Who proposed that plants split water instead of carbon dioxide?
van Niel
What are the two stages of photosynthesis?
light reaction and Calvin cycle
photophosphorylation
the addition of a phosphate group to ADP from light reactions
NADP+
the molecule that temporarily stores energized electrons in the light reaction
carbon fixation
incorporation of carbon into organic compounds
wavelength
the distance between the crests of electromagnetic waves
pigments
substances that absorb visible light
spectrophotometer
measures the ability of a pigment to absorb various wavelengths of light
absorption spectrum
a graph plotting a pigment’s light absorption
Who first demonstrated the action spectrum for photosynthesis?
Thomas Engelmann
Chlorophyll a
the main pigment in photosynthesis; the only kind that can participate directly in the light reactions; is blue-green
Chlorophyll b
an accessory pigment; is yellow-green
carotenoids
an accessory pigment that are various shades of yellow and orange
What are the two important functions of carotenoids?
Absorbing a broader spectrum of colors and photoprotection; dissipating excessive light energy
What atom does chlorophyll have at its center?
Magnesium
What is the afterglow caused by excited electrons falling back to ground state called?
Fluorescence
photosystem
systems that package together chlorophyll, proteins, and other kinds of smaller organic molecules in the thylakoid membrane
antenna complex of a photosystem
a cluster of a few hundred chlorophyll a, chlorophyll b, and carotenoid molecules
reaction center
the region of the photosystem where the first light-driven chemical reaction of photosynthesis occurs; contains a special chlorophyll a molecule
primary electron acceptor
a special molecule in the reaction center that gets reduced (gains an electron) by the chlorophyll a
photosystem I
the photosystem that is best at absorbing light of wavelength 700 nm (the far-red part)
photosystem II
the photosystem that is best at absorbing light of wavelength 680 nm (red part)
What causes the difference in the absorption spectra of photosystem I and photosystem II?
The chlorophyll are associated with different proteins in the thylakoid membrane
noncyclic electron flow
the predominant route during the light reaction
When does the water-splitting step of photosynthesis occur?
In noncyclic electron flow, when Photosystem II gets excited and after needs to be reduced; water is split up to get electrons
What are the molecules in the first electron transport chain for photosynthesis?
Plastoquinone (electron carrier), a complex of two cytochromes, and plastocyanin (a copper-containing protein)
What are the molecules in the second electron transport chain for photosynthesis?
Ferredoxin (iron-containing protein), cytochromes, plastoquinone
NADP+ reductase
an enzyme that transfers electrons from Fd to NADP+
What does the first electron transport chain for photosynthesis create?
ATP
What does the second electron transport chain for photosynthesis create?
NADPH
Explain the steps of noncyclic electron flow briefly:
light excites both photosystem II and photosystem I. In photosystem II, the electron is carried through a transport chain that produces ATP and reduces photosystem I back to ground state. A water is split to get its electrons to reduce photosystem II back to ground state. In photosystem I, the electron is carried through another transport chain that produces NADPH.
cyclic electron flow
when Fd cycles back to the cytochrome complex and back onto photosystem I, thus generating more ATP but no O2 or NADPH
why is cyclic electron flow sometimes necessary?
The Calvin cycle consumes more ATP than it does NADPH, so more ATP needs to be made than NADPH
What is the function of the thylakoid space?
As an H+ reservoir for chemiosmosis
What is the carbohydrate produced directly from the Calvin cycle called?
G3P (glyceraldehydes-3-phosphate)
What does G3P stand for?
Glyceraldehydes-3-phosphate
What is the molecule that CO2 is attached to in the Calvin cycle?
Ribulose bisphosphate (RuBP)
rubisco
the enzyme that catalyzes the incorporation of carbon
What does rubisco stand for?
RuBP carboxylase
What is the most abundant protein in chloroplasts?
rubisco
What is the second carbon product formed in the Calvin cycle?
1,3 bisphosphoglycerate
What is formed immediately after CO2 is fixed?
Two molecules of 3-phosphoglycerate
What does the net synthesis of one G3P molecule take?
9 molecules of ATP and 6 molecules of NADPH
C3 plants
plants in which the first organic product of carbon fixation is a 3 carbon compound 3-phosphoglycerate
photorespiration
when plants use Rubisco to break down O2 to make CO2; generates no ATP and produces no food
C4 plants
plants in which the first organic product of carbon fixation is a four-carbon compound
Examples of C3 plants
rice, wheat, soybeans
Examples of C4 plants
sugarcane, corn, grass
What are the two distinct types of photosynthetic cells in C4 plants?
Bundle-sheath cells and mesophyll cells
bundle-sheath cells
cells that are arranged into tightly packed sheaths around the veins of the leaf
Mesophyll cells (C4 plants)
loosely arranged cells between the bundle sheath cells and the leaf surface
Where is the Calvin cycle confined to in C4 plants?
The chloroplasts of the bundle sheath
What does PEP stand for?
Phosphoenolpyruvate
PEP carboxylase
the enzyme that adds CO2 to PEP
What is the first product created in C4 photosynthesis?
Oxaloacetate
Why do C4 plants make a 4-carbon compound?
This compound releases CO2 to be reassimilated into organic material, thus keeping the CO2 levels high
What are the four main groups of land plants?
Bryophytes, pteridophytes, gymnosperms, angiosperms
What are the most common bryophytes?
Mosses
How are bryophytes distinguished from algae?
Offspring develop from multicellular embryos that remain attached to the “mother” plant
bryophytes
mosses
How are bryophytes distinguished from other land plants?
Bryophytes have no vascular tissue
vascular plants
plants with vascular tissue; includes gymnosperms, pteridophytes and angiosperms
vascular tissue
when cells are joined into tubes that transport water and nutrients throughout the plant body
pteridophytes
have spores instead of seeds; includes ferns
seed plants
plants that reproduce with seeds, includes gymnosperms and angiosperms
seed
a plant embryo packaged along with a food supply within a protective coat
When did the first vascular plants with seeds occur?
Near the end of the Devonian period about 360 million years ago
When did flowering plants occur?
In the early Cretaceous period about 130 million years ago
gymnosperms
conifers
Angiosperms
flowering plants
What algae did plants evolve from?
Charophyceans
rosette cellulose-synthesizing complex
rose-shaped arrays of proteins that synthesize the cellulose microfibrils of cell walls; distinguishes them from algae
phragmoplast
an alignment of cytoskeletal elements and Golgi-derived vesicles that occurs during cross-wall synthesizing in cell division
What four features link plants to charophyceans?
Rosette cellulose-synthesizing complexes, presence of peroxisomes, similar sperm cell structures, similar details of cell division
What five features distinguish plants from charophyceans?
Apical meristems; multicellular, dependent embryos; alternation of generations; walled spores produced in sporangia; multicellular gametangia
apical meristems
localized regions of cell division at the tips of shoots and roots
embryophytes
the characteristic of a multicellular, dependent embryo
alteration of generations
the alternation of two multicellular body forms, each form producing the other
gametophyte
haploid generation that undergoes mitosis to produce gametes
sporophyte
diploid generation from the mitotic division of a zygote that divides meiotically to produce haploid spores
spore
a reproductive cell that can develop into a new organism without fusing with another cell; divides mitotically to produce gametophytes
What distinguishes alternation of generations as a special type of haploid-diploid sexual cycle?
BOTH stages are represented by multicellular bodies
sporopollenin
a polymer that makes the walls of plant spores very tough and resistant to harsh environments
What is the most durable organic material known?
Sporopollenin
sporangia
multicellular organs found on the sporophyte that produce the spores
gametangia
multicellular organs that produces gametes
archegonia
female gamentangia
ectomycorrhizae
when the mycelium of a fungus forms a dense sheath over the surface of the root
What are ectomycorrhizae common in?
woody plants
endomycorrhizae
when the mycelium of a fungus actually extend inward into the cell wall
What percentage of mycorrhizae are endomycorrhizaes?
90%
arbuscles
dense knotlike structures that endomycorrhizae form once they have penetrated the cell wall
epiphyte
an autotrophic plant that nourishes itself but grows on the surface of another plant
flowers
specialized shoots bearing the reproductive organs of the angiosperm sporophyte
What are the four kinds of floral organs?
Sepals, petals, stamens, carpels
receptacle
where the floral organs are attached to
stamen
the male reproductive organ
carpel
the female reproductive organ
sepals
floral nonreproductive organs that enclose and protect the floral bud before it opens; green and more leaflike in appearance than other floral organs
petals
floral nonreproductive organs that advertise the flower to pollinators
What does a stamen consist of?
Filament (stalk) and anther
anther
part of the stamen, produces pollen
What does a carpel consist of?
An ovary and a style (middle neck)
stigma
a sticky structure at the top of the carpel that serves as a landing platform for pollen
ovary
a structure within the carpel that contains ovules
ovule
structure within ovary, is basically the egg
pollen grains
male gametophytes
embryo sacs
female gametophytes
What part of an angiosperm develops into a fruit?
ovary
What part of an angiosperm develops into a seed?
ovule
complete flowers
flowers that have all four floral organs
incomplete flowers
flowers that lack one or more of the four floral parts
bisexual flower
a flower that has both stamens and carpels
unisexual flower
a flower that is missing either stamens or carpels
staminate
a unisexual flower that is missing a carpel
carpellate
a unisexual flower that is missing a stamen
monoecious
when staminate and carpellate flowers are located on the same individual plant
dioecious
when staminate flowers and carpellate flowers are on separate plants
microsporocytes
the diploid cells within the sporangia (pollen sacs) of an anther
microspores
the haploid cells that eventually give rise to a male gametophyte
How many microspores are formed from a microsporocyte?
4
What two cells does the microspore produce from mitosis?
generative cell and tube cell
generative cell
a cell produced from the microspore by mitosis, will eventually produce sperm
tube cell
a cell produced from the microspore by mitosis, will develop into the pollen tube
megaspore
the haploid product of the sporangium of the ovule (megasporocyte); typically are four of them
What happens to the four megaspores?
Only one survives
micrpyle
a gap in the integument of the ovule
endosperm
a food-storing tissue of the seed
What process gives rise to the endosperm?
one sperm combining with the two polar nuclei in an ovule to form a triploid (3n) nucleus
double fertilization
the union of two sperm cells with different nuclei of the embryo sac
hypocotyl
the embryonic axis below the point where cotyledons are attached
radicle
embryonic root
epicotyl
portion of the embryonic axis above the cotyledons
plumule
shoot tip with a pair of miniature leaves
greening
when potatoes that have dark-sprouted start to grow like a normal plant
phytochrome
the receptor involved in greening in plants
Where does the phytochrome that functions in greening occur?
cytoplasm
aurea
a tomato mutant that demonstrated the requirement for phytochrome in greening
second messengers
small, internally produced chemicals that transfer and amplify the signal from the receptor to proteins that cause the specific response
auxin
hormone that stimulates stem elongation, root growth, cell differentiation and braniching
Where is auxin produced?
in the embryo of a seed, meristems of apical buds, young leaves
What was the first plant hormone to be discovered?
auxin
What is the natural auxin occuring in plants also known as?
indoleacetic acid (IAA)
cytokinin
hormone that affects root growth and differentiation, stimulates cell division and growth, germination, delays senescence
gibberellins
promotes seed and bud germination, stem elongation and leaf growth; stimulates flowering and development of fruit, affects root growth and differentiation
Where is gibberellin produced?
meristems of apical buds and roots, young leaves, embryo
abscisic acid
hormone that inhibits growth; closes stomata during water stress; counteracts breaking of dormancy
Where is abscisic acid produced?
leaves, stems, roots, green fruit
ethylene
hormone that promotes fruit ripening, opposes some auxin effects; promotes or inhibits growth and development of roots, leaves, flowers
Where is ethylene found?
tissues of ripening fruits, nodes of stems, aging leaves and flowers
brassinosteroids
inhibits root growth; retards leaf abscisssion; promotes xylem differentiation
synergids
two cells that flank the egg cell and function in the attraction and guidance of the pollen tube
polar nuclei
two nuclei in an embryo sac that share the cytoplasm of the large central cell
integument
protective layers of sporophytic tissue
What cells are in the embryo sac?
One egg cell, two synergids, three antipodal cells, two polar nuclei
self-incompatibility
the ability of a plant to reject its own pollen and the pollen of closely related individuals
eudicots
largest class of angiosperms
amorella
oldest angiosperm
three basic organs of plants:
roots, stems, leaves
cotyledons
seed leaves
monocots
orchids, bamboos, palms, lilies, yucca, grasses
dicots
roses, beans, sunflowers, oaks
differences between monocots and dicots:
Monocots: one cotyledon, parallel leaf veins, vascular bundles arranged in stems, fibrous root system, floral parts in multiples of three
Dicots: two cotyledons, veins usually netlike, vascular bundles arranged in ring, taproot present, floral parts in multiples of four or five
root system
subterranean
shoot system
ground level, stems and leaves
terminal bud
shoot apex
fibrous root systems
monocots, mat of thin roots
taproot system
dicots, one large, vertical root w/ smaller lateral roots
root hairs
increases surface area of root enormously
adventitious
Any plant part that grows in an atypical location (some plants have orots rising aboveground from stems or even leaves, i.e. corn)
vegetative shoot system
leaf bearing
reproductive shoot system
flower bearing
stem
an alternating system of nodes and internodes
nodes
points at which leaves are attached
internodes
stem segments between nodes
axil
angle formed by each leaf and stem
axillary bud
structure that has the potential to form a vegetative branch; most are dormant
apical dominance
phenomenon where presence of the terminal bud is partly responsible for inhibiting the growth of axillary buds
modified shoots
stolons, rhizomes, tubers, bulbs
stolons
grow on surface of ground and enable a plant to colonize large areas asexually when the single parent plant fragments into many smaller offspring, i.e. “runners” of strawberry plants
rhizomes
horizontal stems similar to stolons but underground, i.e. ginger plants
tubers
swollen ends of rhizomes specialized for storing food, i.e. potatoes
bulbs
vertical, underground shoots mostly of swollen bases of leaves that store food, i.e.. onions
leaves
main photosynthetic organ of most plants, consist of blade and petiole
petiole
stalk of leaf, joins leaf to node of stem; many monocots lack petioles
how to classify plants:
leaf shape, spatial arrangement of leaves on a stem pattern of leaf’s veins
tissue systems of plant organs:
dermal, vascular, ground
dermal tissue
aka epidermis, single layer of tightly packed cells that covers and protects all young parts of the plant
cuticle
waxy coating of epidermis of leaves and most stems
vascular tissue
is continuous throughout the plant, involved in transport of materials between roots and shoots; consists of xylem, and phloem
xylem
conveys water and dissolved minerals upward from roots into shoots
phloem
transports food made in mature leaves to roots and nonphotosyntehtic parts of shoot system
tracheids and vessel elements
water-conducting elements of xylem, elongated cells that are dead at functional maturity
pits
thinner regions where only primary walls are present
xylem vessels
long micropipes that are composed of vessel elements aligned end to end
sieve-tube members
tubes that transport sucrose and other organic compounds through the phloem; alive at functional maturity, but lack organelles
sieve plates
end walls b/w sieve-tube members in angiosperms; have pores that facilitate flow of fluid from cell to cell along sieve tube
companion cell
nonconducting cell alongside each sieve-tube member, has organelles like nucleus and ribosome to serve sieve-tube members
ground tissue
simply tissue that is neither dermal tissue nor vascular tissue, divided into pith and cortex in dicot stems, has diverse functions
pith
part of ground tissue, internal to vascular tissue
cortex
part of ground tissue, external to vascular tissue
three basic types of plant tissue:
parenchyma, collenchyma, sclerenchyma
protoplast
cell contents exclusive of the cell wall
parenchyma cells
have relatively thin and flexible primary walls, lack secondary walls, protoplast has large central vacuole, least specialized (known as “typical” plant cells), perform most metabolic functions of plant
collenchyma cells
thicker uneven primary walls, grouped in strands or cylinders, support young parts of plant shoot without restraining growth
sclerenchyma cells
supporting cells, but have thick secondary walls strengthened by lignin, cannot elongate and occur in regions of plants that have stopped growing; many are dead at functional maturity, xylem components are sclerenchyma cells, also fibers and sclereids
fibers
type of sclerenchyma cell, specialized entirely in support, long, slender, tapered, i.e. hemp and flax
sclereids
type of sclerenchyma cell, shorter and irregular in shape, i.e. nutshells and seed coats
biennial
A plant whose life span is two years, mostly those with intervening cold period (Winter) b/w vegetative growth (spring/summer) and flowering (2nd spring/summer)
perennials
Plants that live many years
meristems
perpetually embryonic tissues
initials
Cells that remain as wellsprings of new cells in the meristem
derivatives
new cells that are displaced form the meristem, continue to divide until they are specialized
apical meristems
located at tips of roots and in buds of shots, supply cells for plant to grow in length
primary growth
elongation of apical meristems
secondary growth
woody plants only, progressive thickening of the roots and shoots formed earlier by primary growth, product of lateral meristems
lateral meristems
cylinders of dividing cells extending along the length of roots and shoots
primary plant body
parts of the root and shoot systems produced by apical meristems
root cap
thimblelike, physically protects meristem of root, secretes polysaccharide slime that lubricates soil around growing root tip
zones of cells at successive stages of primary growth:
zone of cell division, zone of elongation, zone of maturation
zone of cell division
includes apical meristem and derivatives, concentrates on mitosis
quiescent center
population of cells near center of apical meristem that divide much more slowly than other meristematic cells, relatively resistant to damage from radiation and toxic chemicals
protoderm
first circle of cells just above apical meristem, will produce dermal tissues
procambium
2nd circle of cells just above apical meristem, will produce vascular tissue
ground meristem
third circle of cells just above apical meristem, will produce ground tissues
zone of elongation
zone where cells elongate, pushes root tip ahead
zone of maturation
where tissue systems become functionally mature
stele
central cylinder of vascular tissue where xylem and phloem develop, produced by procambium
endodermis
cylinder one cell thick forms boundary between cortex and stele in roots of both monocots and dicots; innermost layer of cortex
lateral roots
arise from pericycle in established roots
pericycle
layer of cells that may become meristematic and begin dividing again
vascular bundles
strands of vascular tissue in length of stem
stomata
tiny pores flanked by guard cells; allows gas exchange between surrounding air and photosynthetic cells inside leaf, major avenues for transpiration
guard cells
specialized epidermal cells that border stomata
mesophyll
region between upper and lower epidermis where ground tissue of a leaf is centered; consists mainly of parenchyma cells equipped with chloroplasts and specialized for photosynthesis
palisade parenchyma
mesophyll on upper part of leaf in dicots, cells are columnar in shape
spongy parenchyma
below palisade region, gets name from labyrinth of air spaces through which carbon divide and oxygen circulate around the irregularly shaped cells
secondary plant body
consists of tissues produced during secondary growth (diameter growth)
vascular cambium
lateral meristem that functions in secondary growth, produces secondary xylem (wood) and secondary phloem
cork cambium
produces tough, thick covering for stems and root that replaces epidermis
ray initials
alternating regions of cambium cells that produce radial files of parenchyma cells known as xylem rays and phloem rays, separate wedge-shaped sections of secondary vascular tissue
fusiform initials
cambium cells within vascular bundles, produce new vascular tissue, forming secondary xylem to the inside of the vascular cambium and forming secondary phloem to the outside
wood consists mainly of:
tracheids, vessel elements (angiosperms only), and fibers
characteristics of early wood:
relatively large diameters and thin walls, produced during spring
characteristics of late wood:
relatively small diameters and thick walls, produced during summer
suberin
waxy material that cork cells deposit in walls after they mature and before they die; makes up the Casparian strips
periderm
layers of cork and cork cambium; protective coat of secondary plant body that replaces epidermis of primary body
lenticels
region where periderm has split open, make cellular respiration for trunk cells possible
bark
all tissues external to vascular cambium