BIO 14 Exam 2 Practice Questions
The most direct measure of global photosynthesis is...
Global precipitation rates
Global atmospheric temperature
Global storm intensities
Rate of change in atmospheric oxygen (O2)
Rate of change in atmospheric carbon dioxide (CO2)
The dip in atmospheric CO2 (carbon dioxide) 300 million years ago was most likely caused by ...
Increased photosynthesis with increased CO2 sequestration
Increased volcanic activity
Increased photosynthesis with decreased CO2 sequestration
Decreased photosynthesis with decreased CO2 sequestration
Consumption of plants by dinosaurs
Compared to leaves collected in 2015, stomatal density (number of guard cells per mm^2) on museum-specimen leaves collected in 1815 should be...
The same
Higher than in modern leaves (from 2015)
Lower than in modern leaves
Absent
Not possible to measure
In a farm setting, the seed most likely to germinate in soil where Ψ is -1.0 MPa, is the seed with...
Ψ of 1.0 MPa
Ψs of 1.5 MPa
Ψ of -1.5 MPa
Ψp of -1.5 MPa
DCMU sensitivity
If a cell containing 0.1 M of sucrose with a Ψs of -0.24 MPa is placed in distilled water, what is the Ψp of the cell?
0 MPa
-0.24 MPa
+0.24 MPa
1 MPa
The quickest way for a plant root cell to increase H2O uptake when immersed in distilled water is to ...
Increase rate of the light reactions
Increase rate of the C-3 (calvin) cycle
Increase the number of aquaporins
Increase the activity of aquaporins
Decrease the rate of C-3 cycle
Xylem cells have no crosswalls, but Phloem cells *do* have crosswalls. The presence of crosswalls in phloem cells confers ...
Faster fluid movement between cells
Less strength against collapse
A more negative Ψ to phloem contents
A less negative Ψ to phloem contents
A support to anchor slime plugs
Cell "A' has Ψs of -4.5 MPa and a Ψp of +2.0 MPa. Cell "B" has Ψs of -4.0 MPa and a Ψp of +1.0 MPa. Which way will water flow when the two cells are placed next to eacah other in water?
From A to B
From B to A
From A to external solution
From B to external solution
From both A and B to external solution
Plant pathogens (bacteria) can spread through xylem or through phloem. Compared to xylem spread, pathogens spreading through phloem ...
Spread more rapidly
Accumulate in mature leaves
Have better access to root systems
Have no food supply
All of the above
The reason that 2,4-D is used instead of IAA to control bothersome plant growth is that 2,4-D ...
Is an auxin
Is not an auxin
Causes cell enlargement
Degrades more quickly in the plant
Persists longer in the environment
A mutation that blocks auxin transport (as opposed to blocking auxin synthesis) will prevent ...
Phototropism in Heianthus (sunflower)
Flowering in Helianthus
Cell enlargement
Loosening of the cell wall
All of the above
A mutant poppy unable to break down its own IAA would most likely resemble a normal (wild-type) poppy that ...
Was kept in darkness
Was kept in dry soil
Was treated with IAA
Was treated with Vaseline
Was treated with 2,4-D
When eating a spinach leaf, which of the following is true?
The water in the leaf is a product of the C-3 cycle.
The spinach was most likely grown in an area with low CO2 (200 ppm).
You are getting 50% of the protein in the leaf as RuBP carboxylase (rubisco).
The water in the leaf is a product of the C-4 cycle.
The major pigment you are ingesting absorbs mostly green light.
In one turn of the Calvin cycle, one molecule of CO2 generates…
6 ATP and 6 NADPH.
6 NADH.
One molecule of glucose.
One (CH2O) unit of carbohydrate.
6 ATP.
Most of the molecules removed by plants from the atmosphere are…
N2.
H20
O2
Sugar
CO2
What is accomplished by the separation of light reactions from the C-3 cycle in chloroplasts?
Increased resistance to the herbicide DCMU
Nothing
Rubisco is protected from light reactions that generate oxygen.
It allows so-called "light-reactions" to continue at night.
Increased sensitivity to 2,4-D
Which of these removes CO2 from our present-day atmosphere, and will keep that CO2 out of the atmosphere for the longest time going forward into the future?
Eating soybeans that were grown in 2014
Cutting down large 150-year old trees, then taking logs to Antarctica where they stay frozen
Eating products from soybeans grown in 2011
Allowing trees to grow 150 years old, die, then taking logs to tropical sites where they can decay
Growing young trees for wood, harvesting the wood every 10 years to make into fuel pellets
Water movement into plant cells that possess aquaporins …
All of the other answers are correct.
Can be slowed by aquaporins.
Requires hydraulic lift.
Can be prevented by aquaporins
Is not affected by aquaporins.
Which of the following would force stomata to open?
Stimulate water movement into guard cells.
Subject leaves to darkness.
Increase CO2 content of air.
Treat the plant with ABA (abscisic acid).
Disable the potassium pump in guard cell complexes.
Xylem cells (vessels) comprise more than 90% of a tree trunk. These xylem cells …
Contain water under pressure.
All of the answers are traits of xylem cells.
Are dead.
Are rich in aquaporins
Possess thin flexible walls.
In 2012, it was discovered that mild drought (a 25% decrease in rainfall) was enough to cause collapse of Classic Maya Civilization in southern Mexico, by causing societal disruption and abandonment of cities during critical water shortages in years 800 to 950 AD. The reduction in rainfall was enough for evaporation to become dominant over rainfall, thereby depleting water supplies. Modern-day climate change could repeat this problem in regions with high amounts of transpiration. The most vulnerable region(s) would be …
Deserts
African grasslands
Vast pine forests in Russia and Canada
Tropical forests
Irrigated agriculture
Leaf cuticle has a similar function to …
A condom to prevent fertilization.
Masking tape to hold things together.
Waterproof seal in cracks to prevent older bathtubs from leaking.
Coating on jellybeans to prevent them from drying out
Axle grease to lubricate a wheel.
Which statement about light is true?
An absorption spectrum is a plot of biological effectiveness versus wavelength
Light need not be absorbed to produce a biological effect
A given kind of molecule can occupy any energy level
A pigment loses energy as it absorbs a photon
An absorption spectrum may be a good means of identifying a pigment
The source of H2O in the light reactions of photosynthesis is …
Oxygen
Light
Rain
CO2
Carbohydrates
Stomata open when…
Water has moved out of the leaf by osmosis.
Outward flow of H+ sets up a concentration gradient that moves K+ into guard cells via symport.
Aquaporins protect against water passage across the cell membrane.
K+ flows out of guard cells.
Turgor pressure in the guard cells lessens.
Plants are important to people because
The Calvin cycle can run in the light
All of these
New species are discovered near deep sea thermal vents
The Calvin cycle runs at night
People subsist on plants (we eat them, or we eat organisms that eat plants)
Grasses growing under tree crowns are most likely to be…
C-3 species
Dicotyledons
C-4 species
Decreasing species richness and biodiversity compared to areas with bare ground under tree crowns.
Members of Solanaceae
A xylem cell is touching a leaf cell. For this xylem cell, Ψ = -6.0 MPa and Ψs = 0 MPa. For this leaf cell, Ψs = -10 MPa When these two cells are in equilibrium with each other, the Ψ of the leaf will be. . . .
+6.0 MPa
Zero
-6.0 MPa
-10 MPa
+4.0 MPa
Compared to a spinach leaf in darkness with closed stomata, a spinach leaf in darkness with open stomata will…
Decrease Ψ
Decrease water loss
Decrease Ψs
Conserve water
Increase photosynthesis
Leaf drop by trees in Fall is most important in climatic environments that have
Excess precipitation
Soils that lack nutrients for at least one season of the year
An annual stressful season (cold winters or dry seasons)
All of these
Long cold winters but hot and very wet summers
Some fungal pathogens recognize plants on the basis of plants’ stomatal pores. Which of the following would provide plants with protection against such fungal invasion?
Reinforcing the cell wall in guard cells.
Removing all stomata from the plant.
Changing the spacing between stomatal pores.
Changing the timing of stomatal opening.
Increasing the number of trichomes (leaf hairs).
Which leaf color would be the most efficient collector of visible light?
Black
Blue
Green
White
Red
A research student studied the influence of temperature and light intensity upon CO2 exchange of plants in a greenhouse. During the experiment cellular respiration is not influenced by light intensity and cellular respiration of glucose is completely aerobic. At each temperature CO2 uptake was measured during light exposure and loss of CO2 was measured during the dark period. The light intensity was constant during the light period and was not a limiting factor for photosynthesis. The data collected are presented in the following table. At which temperature does the plant release O2 (oxygen) when exposed to light? (http://tinypic.com/r/hv17x2/9)
At all temperatures
Only in the range of 5 – 20 C.
Only at temperatures over 25C
Only at temperatures over 20C.
Only in the range of 20 – 25 C.
Dr. Sarah Hart studies guard cells in Camellia (Tea). Her graph is given below. Guard cells were removed from leaves and incubated in a bathing solution (medium) with Ψ equal to that of the guard cells. After 30 min under saturating red light guard cells were irradiated with blue light for 30 sec. The pH of the medium was monitored during the experiment. What would be the most plausible conclusion based on the her results? (http://tinypic.com/r/167s48o/9)
Blue light may help guard cells to take up protons from outside into the cell.
Blue light may activate all of the guard cells to give away their energy.
Blue light may be a very effective wavelength of light for the respiration of the guard cells.
Blue light may enhance the ability of guard cells to pump protons out of the cell.
Not only blue light but also other wavelengths of light may help guard cells to transfer protons.
Bulk flow
Occurs in rabbit lungs and in plant stems.
Is regulated by aquaporins in plants.
Acts on cell membranes of guard cells in plant leaves.
Occurs when water crosses a cell membrane in plants.
All of these
Agricultural landscapes that are the most inefficient users of irrigation water are fields
Planted with crops timed to grow at the wettest time of year
Planted with different crops
With soil that encourages plant root development
Planted with one crop (monoculture)
With weeds removed
Shown in the attachment, a xylem cell is touching a leaf cell. For this xylem cell, Ψ = -6.0 MPa and Ψs = 0 MPa. For this leaf cell, Ψs = -10 MPa. At equilibrium, Ψp of the leaf cell is . .
0.0
+6.0 MPa
-6.0 MPa
-10 MPa
+4.0 MPa
Photorespiration
Includes reactions carried out in chloroplasts.
Is catalyzed by PEP carboxylase.
Increases the yield of photosynthesis.
Takes place only in C-4 plants.
Is independent of light intensity.
Most of the solar energy striking a green leaf is …
Reflected from the leaf surface
Converted to carbohydrates
Not absorbed at all
Radiated as heat
Transmitted through the leaf, to be used by leaves beneath
Which of the following accurately describes the relationship between photosynthesis and cellular respiration?
Photosynthesis uses solar energy to convert inorganics to energy-rich organics; respiration breaks down energy-rich organics to make ATP.
The primary function of photosynthesis is to use solar energy to make ATP; the primary function of respiration is to break down ATP and release energy.
Photosynthesis involves the oxidation of glucose; respiration involves the reduction of CO2.
Photosynthesis occurs only in organisms able to make their own food (autotrophs) ; respiration occurs only in organisms that must eat others.
Photosynthesis and respiration occur in separate organelles; the two processes cannot happen in the same cell at the same time.
In C4 plants, CO2
Will be removed from the atmosphere more efficiently at higher temperatures predicted for climate change
Binds to water during carbon fixation reactions
All of these
Is concentrated around RuBP carboxylase
Is sequestered from the atmosphere during night time
In the chloroplasts of C3 plants the light-dependent (energy capture) reactions
Are insensitive to herbicides
Enhance activity of RuBP carboxylase by supplying O2
All of these
Interfere with PEP carboxylase activity
Produce Oxygen
Holding a potted Basil plant upside-down without damaging roots, stems, or leaves will …
Still have xylem fluid moving from roots to leaves.
Reverse xylem flow so that water would move upward toward roots.
Force roots to absorb air from soil.
Force leaves to absorb water from soil.
Prevent light reactions in illuminated leaves.
A stable, equilibrated living plant cell has the following water relations: Ψ = -0.1MPa Ψs = -0.8MPa Ψp = 0.7MPa. After auxin acts upon the cell, the first change in water relations will be …
Ψs = 0.8 MPa
No net change in Ψ
Ψp = 0.4 MPa
Ψp = -0.4 MPa
Ψ = -0.05 MPa
Compared to modern-day species, plants 500 million years ago likely had. . .
Higher densities of guard cells on their leaves.
Chlorophyll with a very different absorption spectrum.
A greater percentage of C-4 species.
No requirement for light
Lower concentrations of rubisco.
Plants can resist drought by altering their behavior in response to environmental change. Which type of environmentally-induced changes in gene expression will best favor the possibility of hydraulic lift?
Enhanced root growth into moist layers.
Increasing cuticle thickness.
Dropping older leaves during drought.
Reducing leaf size during development.
Stomatal closure.
Bug lights” are yellow light bulbs that attract fewer insects in summer nights than do other colors of fluorescent or incandescent light bulbs. The absorption spectrum of insect eye pigment must be … (http://tinypic.com/r/oka15h/9) (http://tinypic.com/r/2d2drw5/9)
Graph E
Graph B
Graph A
Graph D
Graph C
Photosynthesis in green plants occurs only during the day. Respiration in plants occurs
Only at night
Only during the day
In chloroplasts after photosynthesis
All the time
Only when there is enough ATP
Compared to a normal (wild-type) plant, a mutant with leaves of smaller antenna (Photosystem I and Photosystem II) size will …
Show a broader absorption spectrum for chlorophyll.
Have entire plants with increased light harvesting capacity.
All of these
Show a broader action spectrum for photosynthesis.
Increase light harvesting capacity of individual leaves.
The fastest route to send messages from roots to leaves uses…
Auxin.
Stomatal complexes
Dead cells
Phloem
Trichomes
Which statement about aquaporins is not true?
They allow water to pass through a membrane without encountering a hydrophobic environment.
They vary in abundance depending on environmental conditions.
Water movement through aquaporins is active (requires ATP).
Permeability of some aquaporins is subject to regulation.
They are membrane transport proteins
For pollen to germinate on the stigma of a flower, water must rush into the pollen grain. If stigma Ψs = -1.0MPa and stigma Ψp = 0.2MPa, then the water relations of the pollen should be... (answers given in order of Ψ, Ψs, Ψp)
-1.8, +2.0, -3.8
+2.5, -0.5, +1.0
-1.5, -2.5, +1.0
-0.6, -0.8, +0.2
-5.0, -3.5, -1.5
Many plant genes are involved with signals sent by one part of the plant to another, as a way of communicating environmental conditions experienced by different areas of the plant. Roots are least likely to express genes that signal about…
Photoperiod.
Temperature.
Mineral supply (NO3-, PO4-2, K+).
Attack by bacteria, fungi, or nematodes.
Water supply
An improved version of Rubisco that would be a “key innovation” in a potential adaptive radiation of green plants would …
Fail to react with O2.
Break down in the presence of light
React more strongly with O2.
Present a smaller target for incoming photons of light.
Generate more CO2 from 5-carbon RUBP.
If the interior of a plant cell has Ψ of -0.3 MPa, and the cell is placed in a beaker of solution with Ψ of -0.5 MPa, then the cell will…
Equilibrate to Ψ of -0.3 MPa.
Lose water
Gain water
Equilibrate to Ψ of 0.5 MPa.
Equilibrate to Ψ of 0.3 MPa.
Drought affects cell expansion differently in root cells than in leaf cells. Natural selection would favor this difference during a drought because . . .
Roots grow faster, while leaves grow slower.
Root growth slows as leaf growth accelerates.
All of these processes operate to affect cell expansion during drought.
Hydraulic lift becomes less important.
Root system increases the plant’s demand for water.
The molecules that link the light reactions and the Calvin cycle are…
Cytochromes and water
ATP and NADPH
RuBP and CO2
Chlorophyll and carotenoids
Plastoquinone (PQ) and cytochromes
An indoor gardener leaving for vacation completely wraps a potted plant with clear plastic. Temperature and light are left at low intensities. The effect of this strategy is to …
All of these
Destroy cohesion of water molecules in the xylem.
Stop photosynthesis
Cause guard cells to shrink and stomatal pores to open.
Reduce transpiration
Which of the following will lead to lower rates of transpiration?
Bright sunlight
Increased atmospheric CO2
Brisk wind
High soil moisture
Hydraulic lift
In daylight hours, the air spaces inside of a leaf contain…
Less O2 than at night.
PEP carboxylase.
Less CO2 than at night
More CO2 than at night.
More Rubisco than at night
The concentration of CO2 that dissolves in water is much less than that in air. This helps explain why …
Global warming promotes a rise in sea level.
Fewer plants grow under water than on land.
All of these answers are results of the difference between solubility of carbon dioxide in water versus air.
Transpiration cannot occur under water.
Climate change correlates with stronger storm events.
Short day plants such as Morning Glory…
Require short periods of light to flower.
Require short dark periods to flower.
All of these
Photosynthesize during the dark hours.
Photosynthesize during daylight hours.
During hydraulic lift, water is released …
All of these observations/predictions are accurate.
Through stomata on root surfaces.
Mostly from leaves at night.
From roots that absorb water during the day.
Directly into the atmosphere by roots at night.
The driving force for transpiration comes from ...
Conditions outside the plant.
Active metabolism only at the source and at the sink.
Active metabolism throughout the path of water and mineral flow.
Active metabolism throughout the path of carbohydrate flow.
Positive Ψp at the source, combined with lower Ψp at the sink.
This graph shows results of removing leaf hairs by shaving leaves of a plant. For this species of plant, the data indicate... (http://tinypic.com/r/280inuw/9)
All of these answers are supported by the evidence in the graph.
Leaf hairs interfere with water escaping through guard cell complexes.
Leaf hairs absorb and retain water.
Leaf hairs cool the leaf.
Leaf hairs produce defensive compounds.
Compared to that of C3 plants, carbon uptake in C4 plants …
Responds strongly to changes in temperature.
Is rarely expressed in plants of the Pacific Northwest (e.g. Washington state, Oregon, Vancouver, Canada)
Uses a more ancient pathway.
All of these answers are accurate about the comparison between C3 and C4 plants.
Is consistently higher
The herbicide (weedkiller) DCMU binds to…
All of the above
High energy electrons.
Protein in chloroplast thylakoids (grana).
Protein in chloroplast stroma.
Membrane-bound ATP-ase.
People are important to plants because
Domesticated plants (corn) require people to spread the seeds
The Calvin cycle can run in the light
The Calvin cycle can run in the light
All of these
The Calvin cycle is light-independent
If xylem fluid is truly under negative Ψp, then drilling into wood of an actively transpiring tree should produce …
A gradual bleeding out of water.
A spurt of water
A drop in temperature.
An inrush of air
Faster uptake of water by roots.
In the C-3 cycle, carbon dioxide is combined with …
PEP (#-C)
Oxalacetate (4-C)
PGA (3-C)
RuBP
Acetyl CoA (2-C)
Water potential
Is the difference between the solute potential and the pressure potential.
Is defined as 1.0 MPa for pure water under no applied pressure.
Is analogous to the air pressure in an automobile tire.
Is the movement of water through a membrane.
Determines the direction of water movement between cells.
If you work for a bio-prospecting company seeking new sources of plant waxes abundantly produced by individual plants, the most reasonable source to investigate is …
Molten lava from volcanoes.
Plants in dark caves.
Trees in tropical dry forests.
Rainforest trees.
Underwater marine plants.
In underground roots. . .
Stomata allow water to enter the plant.
Stomatal opening is activated by light.
Stomata close in response to darkness.
Stomata close in response to high CO2.
Stomata are absent.
The main advantage to the lack of endwalls in xylem vessel elements is that absence of endwalls …
Allows rapid water movement, with little or no resistance from endwalls
Provides strength to xylem cells by preventing cell collapse.
Provides strength to xylem cells by preventing cell explosion.
Provides a foundation for slime plug formation.
Reduces flexibility of wood.
Photosynthesis by green plants over the past 200 million years has changed the earth’s atmosphere by …
Making it easier for Rubisco to function.
Increasing CO2 levels.
Increasing O2 levels.
Decreasing the fitness of C4 plants.
All of the answers offered here are reasons that photosynthsios by green plant has changed the earth's atmosphere.
Increases in the number or opening of aquaporins …
Release protons into the cell wall.
Increase cell membrane permeability to water.
Are most pronounced in xylem vessels.
Alter water potential outside the cell.
Are most pronounced in ripening fruit.
A research student puts a piece of mango weighing 0.3 gram with a Ψ of -1.0 MPa into a beaker of Coca cola. After twenty minutes, she removes the mango slice and it now weighs 0.25 gram. Therefore…
Coca cola has no Ψp, so nothing can be concluded about the Ψ of Coca cola
The Ψ of Coca cola is less than -1.0 MPa.
The mango piece underwent plasmolysis.
Coca cola has a Ψ greater than -1.0 MPa.
Coca cola has a Ψ of zero, as does distilled water.
Like cells of the proximal tubule of human kidneys, leaf cells in plants…
Burst when Ψp is positive.
Have a cell wall.
Develop positive Ψp.
All of these
Have chloroplasts
Plant adaptations to drought include
All of these
Shallow roots
Leaf drop
Permanently open guard cells
Thin leaves
In the tropics, which of the following puts the greatest limit on plant growth and the type of vegetation?
Precipitation
Wind
PH
Sunlight
Temperature
DCMU is a chemical herbicide. The increase in DCMU-resistant super-weeds in agriculture is most likely due to enzymes or proteins that ...
Are the most abundant protein on earth.
Are convergent evolutionary trends in numerous plant lineages.
Increase fitness of the weeds where DCMU is used as a herbicide.
Increase or intensify competition between weeds and crops.
Are synapomorphic traits in the super-weeds and their relatives.
C-4 photosynthesis (as seen in Corn and Sugar Cane) evolved at a time when the Earth’s atmosphere was …
Six times higher in CO2 than it is today.
Missing
Higher in CO2 than ever before.
Generally more humid than it is today.
higher in O2 than it is today
George Washington completely removed the bark from around a cherry tree but was stopped by his father before cutting the tree down. It was noticed that the leaves retained their normal appearance for several weeks, but that the tree eventually died. The tissue(s) that George left functional was (were) the
Bark
All of these
Phloem
Xylem
Companion and sieve cells
Recently, bacteria and viruses have been seen passing through sieve plates in living phloem. This demonstrates that…
Slime plugs protect wounded phloem from releasing sugar.
Phloem blocks the spread of pathogens.
Pathogens can spread throughout a plant through the phloem.
Slime plugs protect wounded phloem from inrush of air.
Plant defense compounds can prevent microbial infections.
Phloem cells (sieve tube members) are less vulnerable than are animal cells to bursting in water because...
phloem cell Ψp is usually <0.
Phloem is rich in sucrose.
Phloem cells lack a cell membrane.
Phloem cells have cell walls.
Sieve plate pores are unplugged.
Which functional plant cells lack a nucleus?
Companion cells only
Xylem only
Both companion and parenchyma cells
Both xylem and sieve tube cells
Sieve tube cells only
Girdling the branch of a tree …
Commonly is caused by rodents under snow.
Is lethal to the tree.
Provides its greatest benefit to root systems.
Is the removal of xylem from that tree branch
Can happen in winter as well as in summer.
Maple syrup is produced from fluid taken from sugar maple trees in the late winter or very early spring. Why are these trees tapped only during this time of the year?
Sapwood requires cold temperatures to transport fluids.
This is the only time when sugars are transported.
This is the time of year roots are a sink.
All of these
This is when roots serves as a source, and young buds are the sink.
Suppose a vandal damages a historic Beech tree on Tufts’ campus by girdling it with a chainsaw. If the tree dies, it will die because…
Oxygen could not reach the roots.
The roots could not get food.
It was cut down.
The roots could not absorb water.
The leaves could not get CO2.
While visiting your aunt in Ipswich MA, one morning you find a beaver gnawing on a birch tree. You scare it off but not before it has removed a strip of bark all the way around the tree. Despite building a fence around the tree to prevent additional damage, the tree dies after a few months. The first event that would occur in this tree's death would be …
death of the leaves of the tree, because they stopped receiving water from the soil
Death of the leaves of the tree, because they could no longer produce sugars by photosynthesis
Death from loss of transpiration
Death of the roots of the tree, because they would no longer be able to absorb water from the soil
Death of the roots of the tree, because they would no longer be able to receive carbohydrates from the leaves
Sucrose enters a phloem sieve tube…
Because of osmosis.
By ATP-driven active transport.
Because of water potential (Ψ).
By all the mechanisms included in these 5 answers.
Because it is unloaded at the sink.
According to the pressure-flow hypothesis of phloem transport,
The combination of a high turgor pressure in the "source" and transpiration water loss from the "sink" moves solutes through phloem conduits.
Water is actively transported into the "source" region of the phloem to create the turgor pressure needed.
The formation of starch from sugar in the "sink" increases the osmotic concentration.
Solute moves from a high concentration in the source to a lower concentration in the sink.
The pressure in the phloem of a root is normally greater than the pressure in the phloem of a leaf.
Which tissue in the aboveground portion of a plant body contains the least densely packed cells? What is the function of these air spac
Spongy and palisade parenchyma; serves as a source of carbon dioxide for photosynthesis and oxygen for cellular respiration.
Xylem; allows pressure for transport
Collenchyma; serves as a source of oxygen for photosynthesis
Pith; helps with support
Plant tissues that sink when dropped into fresh water.
The table below shows the destination (sink) of translocated carbohydrates in a mature tomato plant. The data indicate that the function of most of the atmospheric CO2 captured by tomato plants is used by the plant to … (http://tinypic.com/r/2wgeo0g/9)
Travel from leaves, to stems, to roots.
Produce deeper roots.
Travel from roots, to stems, to leaves.
Double the rate of leaf production.
Attract animals.
Arrange the following five events in an order that explains the mass flow of materials in the phloem. 1. Water diffuses into the sieve elements. 2. Leaf cells produce sugar by photosynthesis. 3. Solutes are actively transported into sieve elements. 4. Sugar is transported from cell to cell in the leaf. 5. Sugar moves down the stem.
2, 1, 4, 3, 5
1, 2, 3, 4, 5
2, 4, 1, 3, 5
4, 2, 1, 3, 5
2, 4, 3, 1, 5
Which of the following foods is a fruit?
Green beans
Maple syrup
Asparagus
Sugar cane
Artichokes
You are on an expedition through a Costa Rican rain forest and find a plant that has woody growth, parallel leaf venation, and flower parts in multiples of four. Why is the botanist of the group incredulous?
It represents a hybrid between monocot and dicot plants.
It is native to Massachusetts.
It is a newly discovered monocot.
It doesn't fit either of the major categories for flowering plants and may represent a lost link in evolution.
It is a newly discovered dicot.
Suppose you could turn a potted plant upside-down without affecting the function of roots, stems, and leaves. What would be the most probable direction of transport in phloem for the upside-down plant?
Phloem contents diffuse through stomata.
Phloem contents move downward by mass flow (bulk flow).
All of these predictions are accurate.
Phloem contents move upward from source to sink.
Water is released by roots to the soil.
Suppose you could connect an active xylem vessel from a stem to an active phloem sieve tube member from a leaf using a ‘micropipe’. Suppose that connection does not wound the plant. Which way would the solution flow between the two?
Flow of the solution would be prevented by influx of air.
The solution would flow back and forth from one to another.
The solution would flow from phloem to xylem.
The solution would flow from xylem to phloem.
The solution would not flow between the two.
A tree will have the largest fruit when
There are many sinks on the tree
There is a low ratio of source to sink
There is a high ratio of source to sink
There are many sources on the tree
Fruit drop is minimal
In Massachusetts, the unusual cold weather in April 2014 will force a 2-week delay in flowering for apple trees whose fruits normally ripen in October. Therefore the 2014 Massachusetts apple crop …
May ripen during short days.
Cannot get pollinated.
May ripen before flowering.
Will ripen in August.
Cannot produce full-size apples
What mechanism explains the movement of sucrose from source to sink?
Osmotic movement of water into the sucrose-loaded sieve-tube members, creating a higher pressure in the source than in the sink.
Starch breakdown into sucrose in leaf cells that raises leaf cell water potential and drives the bulk flow of sap to the sink.
Evaporation of water and active transport of sucrose from the sink.
Active transport of sucrose through sieve-tube members driven by proton pumps.
Tension created by the differences in pressure in the source and sink.
Stamens (pollen sacks) were removed from Brassica which was then treated with NAA. Fruit development was then measured over time. In this experiment, NAA was used to replace auxin normally produced by …
Pollen cell walls.
Seeds.
The ovary wall.
2,4-D.
The stigma.
In coleoptile tissue, auxin…
Can be transported toward either the tip or base depending on the orientation of the coleoptile with respect to gravity.
Is transported from tip to base.
Is not transported, since auxin is used at its site of synthesis.
Is transported by diffusion, with no preferred direction.
Is transported from base to tip.
This action spectrum of phototropism (plant bending toward light--data points with green curve)) for Sunflower shows (http://tinypic.com/r/14sjvig/9)
Only blue light at 450 nm will cause bending.
The plants will not bend toward sunlight
Blue light will cause the most bending.
Yellow light will cause the most bending.
Sunflower bending responds mostly to the same two colors as does photosynthesis.
The most immediate effect of auxin on a plant cell is to…
Decrease Ψs
Increase Ψs
Increase Ψp
Decrease Ψp
Remove protons (H+) from the cell wall.
Compared to domesticated honeybees, native bees…
Are transported from California (almonds) to Florida (citrus).
All of these
Are immune to pesticides.
Depend more heavily on commercial crops for pollen
Can certainly pollinate commercial crops
Flowering in most plants depends upon…
Competition from other flowering species.
Length of uninterrupted darkness.
Competition from non-flowering species.
Average daily temperatures.
Amount of daily rainfall.
Interrupting a night-period with light will
Inhibit flowering
Inhibit photosynthesis
Increase photosynthesis
Promote flowering
Enhance Pfr concentration
Which is the most accurate statement?
Vegetables grow larger after pollination.
Flowers develop from fruits.
Fruits develop from vegetables.
Vegetables develop from fruits.
Fruits develop from flowers.
Colony collapse disorder (CCD) and the “pollination crisis” will most directly affect production of …
Methane.
Livestock.
Fruits
Vegetables.
Pine forests
Storing fruit in controlled atmosphere storage is similar to testing phloem transport between sources and sinks. Both involve…
Suppressing respiration rates by lowering temperature.
Increased oxygen flow to the sink.
All of these
Using cyanide to suppress ripening.
Using ethylene to begin ripening.
The growth regulator that promotes root formation in plant cuttings is…
IAA
Ethylene
2,4-D
TIBA
All of these
Auxin is produced mostly by . . .
Stem tips.
Flowers in full bloom.
The underside of leaves.
Ethylene.
phloem.
The widely-used herbicide (weedkiller) 2,4-D…
All of these
Causes shoots to bend toward gravity.
Causes curvature when placed on the side of a growing coleoptile.
Has two photoconvertible forms
Promotes flowering in short-day plants.
Which of the following statements is not true about what is occurring in the experiment pictured in the attachment? (http://tinypic.com/r/jsiys6/9)
When tips are removed, application of IAA will trigger plant growth.
When tips are exposed to light, auxin induces plant growth through increased cell division.
When tips are lit from one side only, auxin accumulates on the shaded side causing it to grow more than the illuminated side.
When tips are removed, no auxin is made, so the stems do not grow.
When tips are covered, auxin moves to all parts of the stem causing all parts to grow.
Compared to sepals, the yellow petals at the edge of a sunflower are…
Small and inconspicuous
Essential to wind pollination
Carbohydrate sinks
All of these
Green
The plant part least often defended against herbivory is the
Young leaf
Ovary wall of ripe fruit
Seed in ripe fruit
Root
Mature leaf
Most of the edible flesh of a durian, mango, or apple is
Ovary
3N (triploid)
4N (tetraploid)
1N (haploid)
Egg
Compared to an apple tree dropping young fruits, trees that retain all their apples until harvest season will have …
All of the other answers are correct.
A smaller source : sink ratio (source/sink).
Larger and more numerous apples.
A larger source : sink ratio (source/sink).
Smaller but fewer apples.
The graph below shows an action spectrum of phototropism Iplant bending toward light) for Sunflower. The action spectrum supports the prediction that the pigment used by the plant to perceive the direction of light for bending is … (http://tinypic.com/r/14sjvig/9)
Violet-blue
Blue
Chlorophyll
Yellow
Auxin
To force a short-day plant to flower, you must…
Allow fruits to develop.
Provide short periods of light
All of these
Allow pollination to take place.
Provide long periods of darkness.
A plant axis that has flowered…
Will always produce vegetables.
Might return to leaf production after flowering.
All of these
Will always produce fruit.
Will never produce leaves again.
Red tomatoes are kept in a refrigerator at home. Adding a compound that absorbs ethylene from inside the refrigerator will …
Induce flowering.
Delay rotting of the tomatoes.
Accelerate ripening in tomatoes.
Delay the tomatoes from ripening.
Delay the tomatoes from turning green.
Self pollination
All of these
Increases outcrossing
Is most common in wild species
Does not occur in crop plants
Reduces genetic diversity
Membrane-bound auxin transport (efflux) proteins CANNOT be found in …
Stems
Leaves
Phloem
Xylem
Roots
Honeybees do best when supplied with
one staple crop, such as orange blossoms.
Large amounts of pollen for their diet.
Parasitic mites.
Large varieties of pollen for their diet.
one staple crop, such as wheat.
The dramatic reduction in honeybee numbers from CCD (colony collapse disorder) will most strongly impact …
Agricultural C-3 grasses such as rice and wheat.
Vegetable farmers.
Agricultural C-4 grasses such as corn and sugar cane.
Pumpkin farmers
Grasses in the wild
In Bio 14 lab, fruit development in Brassica was blocked by preventing pollination. After pollination was blocked, plants were able to make large fruits only if …
Their pollen produced auxin.
Their seeds produced auxin.
They were insensitive to 2,4-D.
Their ovary wall failed to respond to auxin.
Plants were rescued by externally applied auxin
A treatment will render plants short and stocky when that treatment…
Decreases cell division
All of these
Bleaches chlorophyll
Shortens internodes
Confines roots (Bonsai)
The suppression of lateral bud outgrowth by the terminal bud (shoot tip). . .
Is called ‘dominant-recessive’.
All of these answers are correct.
Increases during flowering.
Allows plants to branch.
Stops when insects consume the shoot tip.
For a Short-Day-Plant, interrupting a day-period with 30 minutes of darkness before returning to light will …
E. increase Pfar red concentration over 24 hours.
Decrease photosynthesis.
Promote flowering.
Increase photosynthesis.
Inhibit flowering.
Crops that require bees or other insects to pollinate them are…
Rice
Seedless watermelons
Corn
Self-pollinating beans, tomatoes, and eggplants
Wheat
Cross pollination is enhanced by flowers
Expressing self incompatibility
With styles much shorter than stamens
All of these
With pollen and eggs maturing at the same time
With stigmas that touch stamens
The role of PIN proteins in auxin function in intact plants is to …
Convert plants to a pin-like shape when present.
Label IAA for auxin-degrading enzymes.
Move auxin from one cell to another
All of these processes are part of the role of PIN proteins.
Selectively bind to synthetic auxins 2,4-D and NAA.
The difference between fruits and vegetables is that fruits …
Develop after pollination.
All answers are correct.
Require auxin for cell expansion
Are sweet.
Are not bitter at any stage of development.
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