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188 terms

MB Topics 6, 7, 8, 9, and 10

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Ovules are housed within the
ovaries
What is unique to flowering plants
double fertilization
The male gametophytes of flowering plants are also referred to as
pollen grains
In flowering plants the integuments of the ovule develop into a
seed coat
A carpel is composed of
stigma, style, and ovary
In flowering plants one megaspore gives rise to ? nuclei
eight haploid
A stamen consists of
anther and filament
In angiosperms, pollination is the transfer of pollen grain to the ? of a flower on the same plant or another plant of the same species
Stigma
Double fertilization in the life cycle of seed plants results in the production of a
diploid zygote and a triploid endosperm nucleua
Where is the megasporangium
within an ovule contained within an ovary of a flower
Gymnosperms and angiosperms have what in common
ovaries
What is true of stamens, sepals, petals, carpels, and pinecone scales
They are modified leaves
What adaptations should one expect of the seed coats of angiosperm species whose seeds are dispersed by animals
The seed coat should be able to withstand low pHs; The seed coat should be resistant to the animals' digestive enzymes
How have fruits contributed to the success of angiosperms
by facilitating dispersal of seeds
In onions (Allium), cells of the sporophyte have 16 chromosomes within each nucleus. How many chromosomes should be in a tube cell nucleus?
8
In onions (Allium), cells of the sporophyte have 16 chromosomes with each nucleus. How many chromosomes should be in an endosperm nucleus?
24
Hypothetically, one of the major benefits of double fertilization in angiosperms is to
coordinate developmental timing between the embryo and its food stores
Which of the flower parts develops into the pulp of a fleshy fruit
ovary
What should be expected of the fruit if the viscosity of Viscum seeds is primarily an adaptation for dispersal rather than an adaptation for infecting host plant tissues
It should be nutritious
The ? is the outmost layer of tissue
epidermis
In leaves, chloroplasts are found in ?
palisade mesophyll
Guard cells regulate
the opening and closing of stomata
What is not a type of primary meristematic cell found in apical meristems
vascular cambium
What structure determines the direction of root growth by sensing gravity
root cap
T/F? Plant growth involves both the production of new cells by mitosis and the expansion of cell volume
True
Vascular cambium
a layer of undifferentiated cells that develops into secondary xylem and phloem
Why do plants need secondary growth
to provide structural support for the plant
What part of the plant remains on the plant even after several years of growth
primary xylem
T/F? Primary growth can occur at both the apical and lateral meristems at the tips of the roots and stems in a plant
False
Secondary growth NEVER occurs in
leaves
? provides cells for secondary growth
vascular cambium
Vascular cambium forms wood toward the stem's ? and secondary phloem toward the stem's ?
center...surface
What is the function of cork
insulation and waterproofing
How is the supply of vascular cambium maintained
by the division of its cells
Mycorrhizae
mutualistic associations of roots and fungi
In roots the ? forces water and solutes to pass through the plasma membranes of ? cells before entering the ?
Casparian strip...endodermis...xylem
Provides the major force for the movement of water and solutes from roots to leaves
Transpiration
? bonds are responsible for the cohesion of water molecules
Hydrogen
Which tissue acts as a filter on the water absorbed by root hairs?
Endodermis
T/F? Root pressure can move water a long distance up the xylem because of the higher water potential of the xylem in comparison to the water potential in the surrounding cells
False
Pressure-flow hypothesis
the mechanism that explains the movement of sugars throughout a plant
Sink
area where sugars are used or stored
Xylem transport
Water and minerals move through the root cortex into the xylem and upward through the stem and into leaves
The rates of photosynthesis and transport in a plant on a dry cloudy day
Both the photosynthesis and transpiration rates are low
T/F? The rate of sugar transport in a plant depends on the rate of photosynthesis, the rate of transpiration, and the difference in turgor pressure between the source and the sink
False
What process is responsible for leaves being considered sugar sources
photosynthesis
? transports sugars from leaves to, for example, taproots
Phloem
Sugar moves from leaves into the ? of ? by ?
Sieve tube members...phloem...active transport
Bulk flow
the water pressure that pushes water and sugar from sugar source to sugar sink
Water moves into phloem by
osmosis
At a sugar sink, sugar is removed from phloem by
active transport
In a sugar sink, such as a taproot, sugar is converted into ?
starch
? is responsible for the movement of sugars from leaves to taproots; ? is responsible for the movement of sugar from taproots to leaves
Bulk flow...bulk flow
The release of CO2 into the soil resule in the formation of ?
hydrogen ions and carbonate ions
What process is the source of the CO2 that root hairs release into the soil
respiration
The binding of H+ ions to soil particles
displaces mineral cations
What ion is most likely to be leached from the soil
chlorine ions
? decreases soil fertility
Acid precipitation
How do cations enter root hairs
diffusion
What are the largest particles formed from the breakdown of rock
gravel
T/F? Soil texture affects the amount of water available to plants; water is held best by clay and sand particles
False
T/F? Plants use both active and passive transport ions against their concentration gradients
False
Nitrogens role as a plant nutrient
Nitrogen-fixing bacteria in the soil convert N2 to NH3. Nitrogen is a component of nucleic acids, proteins, hormones, and coenzymes. Nitrogen is a macronutrient in plants. Plant roots can only absorb nitrogen in the form of ammonium ions or nitrate ions. Nitrogen deficiency usually causes plant leaves to turn yellow
Why do fleshy fruits often have seeds with very tough seed coats
So the seeds can survive the mechanical forces and conditions in an animal's gut
What characteristics the fruit of seeds that are dispersed by the wind
They have structures to extend the distance they travel on the wind
T/F? Fruits provide food to the developing plant
False
Which part of a flower develops into the seed
Ovule
Term that describes the portion of a peach that can be eaten by humans
Pericarp
T/F? The endosperm tissue that nourishes the developing plant has the same nutritional characteristics regardless of the plant species
False
Which part of a plant attracts pollinators
Petals
Which process involves the transfer of pollen grains from an anther to a stigma
Pollination
T/F? The endosperm in a seed develops into the embryo
False
What term describes the male gametophytes of flowering plants
Pollen grains
Which structure formed by the male gametophyte allows sperm to reach the ovary of a flowering plant
Pollen tube
How is fertilization in flowering plants different from fertilization in other plant groups
One sperm nucleus fuses with the egg to form a diploid zygote, whereas the other sperm nucleus fuses with two polar nuclei to form a cell that develops into endosperm
What is endosperm
via cotyledons, a source of food for the embryo
Fruits evolved primarily as structures specialized to ?
disperse seeds
The breakdown of chlorophyll reveals the ? pigments of a leaf
carotenoid
The formation of the abscission layer cuts off transport of substances to and from the leaf. As the concentration of sugar trapped within a leaf increases, ? pigments are produced
anthocyanin
The protective layer that forms between the abscission layer and the stem consists of ?
densely colored cells filled with a waxy layer
After leaf abscission, growth will resume from the ?
axillary bud
? trees lose their leaves in preparation for winter
Deciduous
For a short-day, the ? is critical in determining if flowering will occur
minimum number of hours of darkness
For a long-day plant, the ? is critical in determining if flowering will occur
maximum number of hours of darkness
Day-neutral plants flower regardless of ?
day length, night length, or photoperiod
Which color of light do plants grow toward
blue
What term describes the directed growth of plants in response to light
phototropism
Which type of light is not absorbed strongly by photosynthetic pigments
Far-red
T/F? A high level of far-red simulates shady conditions to a plant
True
What event could cause a plant that normally grows in a sunny habitat to dramatically elongate its stem
The plant was exposed to a high level of far-red light
How would a plant that normally grows in a shady habitat respond when exposed to a high level of far-red light
Its stem would not elongate because it grows well in far-red light
What is the physical basis of the phototrophic response
cell elongation
T/F? Auxin is asymmetrically distributed in shoots because the auxin on the side of the plant facing the source of light is destroyed
False
Where does the majority of stem growth in a plant occur
Apical meristem
Hormones can function
at very low concentrations
Which term describes the direction of auxin transport in a plant
polar
How does auxin produce gravitropism in a plant that is placed on its side
Auxin accumulates on the lower surface of the root and inhibits elongation of cells in that region
How does auxin produce phototropism
Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation
What organism does not cause disease in plants
Herbivore
Which structure does not protect stems and leaves from damage by herbivores
stomata
T/F? Plants do not produce many defenses against pathogens unless they are threatened because defensive structures and compounds require much energy and materials to produce and maintain
True
What is the initial localized response of a resistant plant to pathogen invasion
Hypersensitive response
Which compound is not used in the localized response to pathogen invasion to poison organisms that attack a plant
salicylic acid
How does a plant defend against herbivores
The hormone systemin is produced at the site of injury and signals the plant to produce proteinase inhibitors
What is derived from the ground tissue system
pith
Which part of a plant absorbs most of the water and minerals taken up from the soil
root hairs
A person working with plants may remove apical dominance by doing which of the following
pruning
? is to xylem as ? is to phloem
vessel element; sieve-tube member
CO2 enters the inner spaces of the lead through the
stoma
Relatively unspecialized cells that retain the ability to divide and perform most of the plant's metabolic functions of synthesis and storage
parenchyma cells
The vascular bundle in the shape of a single central cylinder in a root is called the
stele
Plants contain meristems whose only function is to
divide
What arises from lateral meristem activity
secondary xylem
The driving force that pushes the root tip through the soil is due primarily to
elongation of cells behind the root apical meristem
Which root tissues gives rise to lateral roots
pericycle
Pores on the leaf surface that function in gas exchange are called
stomata
What tissue makes up most of the wood of a tree
secondary xylem
"Totipotency" is a term used to describe the ability of a cell to give rise to a complete new organism. In plants, this means
cell differentiation depends largely on the control of gene expression
A plant developed a mineral deficiency after being treated with a fungicide. What is the most probable cause of the deficiency
Mycorrhizal fungi were killed
Root hairs are most important to a plant because they
increase the surface area for absorption
A water molecule could move all the way through a plant from soil to root to leaf to air and pass through a living cell only once. This living cell would be a part of which structure
the endodermis
What regulates the flow of water through the xylem
the evaporation of water from the leaves
What is responsible for the cohesion of water molecules
hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule
All of the following normally enter the plant through the roots except
carbon dioxide
What kind of day would result in the fastest delivery of water and minerals to the leaves of a tree
warm, dry day
Guard cells are the only cells in the epidermis that contain chloroplasts and can undergo photosynthesis. This is important because
ATP is required to power proton pumps in the guard cell membranes
Phloem transport of sucrose can be described as going from "source to sink." Which would not normally function as a sink
mature leaf
Explain the mass flow of materials in the phloem: water diffuses into the sieve tubes, leaf cells produce sugar by photosynthesis, solutes are actively transported into sieve tubes, sugar is transported from cell to cell in the leaf, sugar moves down the stem
Leaf cell produce sugar by photosynthesis, sugar is transported from cell to cell in the leaf, solutes are actively transported into sieve tubes, water diffuses into the sieve tubes, sugar moves down the stem
Water flows into the source end of a sieve tube because
sucrose has been actively transported into the sieve tube, making it hypertonic
If you wanted to increase the cation exchange and water retention capacity of loamy soil, what should you do
add clay to the soil
What is the fate of most of the water taken up by the plant
it is lost during transpiration
Why does over-watering a plant kill it
The roots are deprived of oxygen
The N-P-K percentages on a package of fertilizer refer to the
percentages of three important mineral nutrients
Most of the dry weight of a plant is the result of uptake of
CO2 through stoma
Which essential nutrients plays an essential role in the opening and closing of the stomatal aperture
K
What is the general role of micronutrients in plants
They are cofactors in enzymatic reactions
Why is nitrogen fixation such an important process
Fixed nitrogen is most often the limiting factor in plant growth
Among important crop plants, nitrogen-fiing root nodules are most commonly an attribute of
legumes
Dwarf mistletoe grows on many pine trees in the Rockies. Although the mistletoe is green, it is probably not sufficiently active in photosynthesis to produce all the sugar it needs. The mistletoe also produces haustoria. Thus dwarf mistletoe growing on pine trees is best classified as
a parasite
Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of
nitrogen
At the conclusion of meiosis in plants the end products are always four haploid
spores
Correct sequence during the alternation of generations life cycle in a flowering plant
sporophyte, meiosis, gametophyte, gametes, fertilization, diploid zygote
What is true of most angiosperms
a triploid endosperm within the seed, and an ovary that becomes a fruit
Location of the microsporangia
stamen
A perfect flower is fertile, but may be either complete or incomplete. What correctly describes a perfect flower
It has both stamens and carpels
What type of plants is not able to self-pollinate
dioecious
What is the male gametophyte of a flowering plant
pollen grain
Fruits develop from
ovaries
What is the first step in the germination of a seed
imbibition of water
Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the
tip of the coleoptile
Plants bend toward light because
cell expansion is greater on the dark side of the stem
The apical bud of a pine tree inhibits the growth of lateral buds through the production of
auxin
The ripening of fruit and the dropping of leaves and fruit are principally controlled by
ethylene
When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division
cytokinin
The synthesis of ? would be an attempt to produce normal growth in mutant dwarf plants
gibberellin
Currently the most powerful method of research on plant hormones
analyzing mutant plants
A short-day plant will flower only when
nights are longer than a certain critical value
A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely
have no effect upon flowering
The transduction pathway that activates systemic acquired resistance in plants is initially signaled by
salicylic acid
The chemical signal for flowering could be released earlier than normal in a long-day plant exposed to flashes of
red light during the night
If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering
14 hours light/10 hours dark
Fungi produce ? spores
haploid
Karyogamy produces a ?
diploid zygote
Plasmogamy
fusion of hyphae
Which stage in the fungal life cycle contains two haploid nuclei
the heterokaryotic stage
Zygosporangia are
heterokaryotic
Karyogamy produces a
diploid zygote
Cup fungi are in the phylum
Ascomycota
In sac fungi, karyogamy and meiosis occur in
asci
A nucleus within an ascus undergoes meiosis, producing four haploid spores, which then undergo mitosis, producing eight haploid ascospores. These haploid ascospores contain a maximum of ? different genetic types
four
A mushroom is a
basidiocarp
In club fungi, karyogamy and meiosis occur in
basidia
All fungi are
decomposers of organic matter
Fungi compete with bacteria by producing
antibiotics
Symbiosis is
a close association between two organisms
If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed
prokaryotes
In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae
pores in cross walls
Consider two hyphae having equal dimensions: one from a septate species and the other from a coenocytic species. Compared with the septate species, the coenocytic species should have
less chitin
In most fungi, karyogamy doe snot immediately follow plasmogamy, which consequently
results in heterokaryotic or dikaryotic cells
You have been given the assignment of locating living members of the phylum Glomeromycota. Where is the best place to look for these fungi?
The roots of vascular plants
Zygosporangia are to zygomycetes as basidia are to
club fungi
The gray-black, filamentous, haploid mycelium growing on break is most likely what kind of organism
zygomycete
What fungal structure is usually associated with asexual reproduction
conidiophore
Arrange from largest to smallest: ascospore, ascocarp, ascomycete, ascus
ascomycete, ascocarp, ascus, ascospore
Mushrooms with hills have meiotically produced spores located in or on
basidia
If all mycorrhizae were somehow disrupted, what would occur
most vascular plants would be stunted in their growth
A billionaire buys a sterile volcanic island that recently emerged from the sea. To speed the arrival of conditions necessary for plant growth, the billionaire might be advised to aerially sow what over the island
soredia
What condition is caused by a fungus that is accidentally consumed along with rye flour
ergotism