Unit 3 Practice Questions (Plants and Growth Models)

In a population of daffodils, a mutation arises that results in xylem vessels that are 3 times narrowerthan the wild-type variety. Compared to the wild-type, the mutants will have _______ water transport capacity, but will also be _______ susceptible to cavitation from freezing.

lower; less

Where is cellulose found?

plant cell walls

Xylem use _____ pressure and phloem use _____ pressure.

Negative (pull); positive (push)

Describe whether the phloem and xylem can act independently of each other.

Only the xylem can act independently of the phloem. The phloem requires water from the xylem to move sugar. Thus, if they phloem was cut, transpiration would occur normally. However, if the xylem was cut, the phloem was be affected in that there would be no water to move sugar within the phloem, thus sugar would accumulate and photosynthesis would be signaled to stop

Explain how you can collect drinkable water from trees and describe the path of water through the plant. Use the correct plant terminology.

Transpiration moves the water from the soil/groundwater through the roots, up into the xylem, and then the water vapor exits the plant through the stomata

when stomata are open, CO2 (1)_______ and water (2)_______

(1) enters (2) exits

Phloem sap moves carbohydrate/glucose/sugars from sources to sinks. Describe what the sources and sinks are in this context.

*Source* = Carbohydrates are *made* here and moved to other parts of the plant; or, carbohydrates are *stored* here and moved to other parts of the plant. *Sink* = Carbohydrates are *used* here or carbohydrates are moved here for storage (cellular respiration or sugar storage)

Phloem sap moves carbohydrate/glucose/sugars from sources to sinks. Identify each of the following as either a source or sink: leaves, roots, flowers, fruits, growing leaf buds, a potato (the tuber underground) growing in the summer, a seed potato (the tuber underground)sprouting in the spring.

*Source*: leaves, seed potato sprouting in the spring *Sink*: roots, flowers, fruits, growing leaf buds, potato growing in the summer

Carbon neutral means net zero carbon emissions. Why might biofuels be considered carbon neutral?

- Growing biofuels take CO2 out of the atmosphere - Burning biofuels produces CO2 (Depends on how much energy is used to grow, harvest, and process the fuel)

Some plants have special adaptations for waterlogged soils (which don't have enough oxygen). Give examples.

- Roots above the soil/water line in mangroves - Air spaces in roots of water lilies (connected to stems/leaves)

Why is it easier to make ethanol from starch than it is to make ethanol from cellulose?

- Starch is easier to break down than cellulose is - Enzymes that break down starch are easier to use in industrial settings and more abundant - Takes less work, energy, and technology to digest starch than cellulose

Decide whether each of the following would increase or decrease the movement of sap through phloem. 1. Increase photosynthesis in leaves. 2. Cover the sieve tube cells with a waxy cuticle. 3. Inhibit the transport proteins that load sucrose from mesophyll cells into sieve tube cells.

1. Increase 2. Decrease (waxy cuticle is impervious to water, meaning that it prevents water from going through) 3. Decrease

Density-dependent or density-independent? 1. During a drought, many plants die and this causes the insects that feed on these plants to also die. 2. A dangerous new flu strain that is transmitted among humans by sneezing. 3. The first hard frost of fall for a population of sun-loving shrubs in an abandoned field. 4. A tidal wave wipes out the entire population of mice living on an island causing death rates to increase. 5. Cheetahs stake out their territory using chemical communication to warn other cheetahs to stay away. 6. Birds compete for nesting sites in trees, if there are more birds than nesting sites then some birds will be unable to lay eggs. 7. The space of a habitat for large animals like elephants. 8. An environment has two square-miles of grass for cows to feed on.

1. Independent 2. Dependent 3. Independent 4. Independent 5. Dependent 6. Dependent 7. Dependent 8. Dependent

You plant potatoes in your garden starting with seed potatoes. Seed potatoes aren't seeds, they're pieces of potato tuber that you can use to grow new potato plants. You watch the above-ground development of each plant and categorize the growth into the following stages: spring, early summer, and late summer. For each stage, decide whether the main movement of carbohydrates is from roots to shoots, shoots to shoots, or from shoots to roots. Roots are the belowground parts of the plant and shoots are the aboveground parts of the plant. 1. Spring: the initial development of the stem and leaves. 2. Early summer: the development of flowers and growth of the aboveground plant parts. 3. Late summer: a vegetative period where not much aboveground growth seems to be happening, but new potatoes are forming underground.

1. Roots to shoots 2. Shoots to shoots 3. Shoots to roots

True or false regarding xylem and phloem? 1. Water exiting the phloem may enter the xylem and be transported to leaves. 2. In xylem, the plant's metabolic activity generates the energy that drives water transport. 3. Movement of phloem sap in phloem is largely driven by transpiration

1. T 2. F 3. F

True or false regarding why the presence of high concentrations of salts in soil poses a problem for plants. 1. Salts in soil can make it harder for the root to get water from the soil. 2. If the salts are not filtered from the transpiration stream, they can damage the plant. 3. Salts can form insoluble compounds with organic forms of nitrogen that are then unavailable to the plant. 4. If taken up by the shoot, salts make the plant more palatable to large herbivores

1. T 2. T 3. F 4. F

Angiosperms have *wider xylem vessels* than gymnosperms. Gymnosperms often dominate high- latitude boreal forests, whereas *angiosperms dominate rainforests* because gymnosperm xylem: A. are less susceptible to freezing-induced cavitation, but less efficient for moving large volumes of water. B. do not freeze as easily, maintaining flow to support photosynthesis at colder temperatures, which is not an advantage in the tropics. C. mature more quickly, allowing gymnosperms to make more efficient use of the shorter growing seasons of boreal forests. D. better withstand the large tensile forces required to extract water from frozen soils, but offer no advantage in warm tropical soils.

A

In C3 plants, you would expect to find high concentrations of the enzyme Rubisco in: A.Mesophyll cells B. Bundle sheath cells C.Guard cells D.Stomata E.Phloem cells

A

What crop is used to produce most of the ethanol in the US? A. Corn B. Soybeans C. Sugar cane D. Wheat

A

What will happen to rates of photorespiration at 1% compared to 21% O2 levels? A.Rates of photorespiration will be lower in 1% compared to 21% O2 levels. B. Rates of photorespiration will be higher in 1% compared to 21% O2 levels C. There will be no change in rates of photorespiration based on O2 levels.

A

Which of the following is an assumption of the logistic growth model? A. Carrying capacity is constant/unchanging. B. Population growth rate is constant/unchanging. C.Unlimited resources. D. Population size is constant/unchanging.

A

Which of the following statements are true? I. Xylem vessels are long hollow tubes. II. Water and carbohydrates can only move in one direction through phloem. III. The walls of xylem vessels repel water. A. I only B. I and II C. II only D. II and III E. I-III

A

A population 1000 of rabbits is subject to logistic growth. Under normal conditions, this population grows at a rate of 0.5 rabbits per individual per year; however, the maximum number of rabbits the ecosystem can hold is 5000. Because of this, only 400 rabbits were added to the population this year. What is K in this population? A. 5000 rabbits B. 400 rabbits C. 1000 rabbits D. 0.5 rabbits Identify all of the terms in the problem above.

A 5000 rabbits = K 400 rabbits/year = dN/dt 1000 rabbits = N 0.5 rabbits/rabbit/year = r

Grapes are C3 plants. You observe that grapes growing on a vine shrink during the day and only grow in size at night. Would the grape fruits be considered a source or sink for phloem sap? A. Source B. Sink C. Depends on the time of the growing season. D. Depends on the time of day.

B

What happens to population growth rate as N approaches K (point B)? A. Population growth rate increases. B. Population growth rate decreases. C. Population growth rate is equal to zero. D. Population growth rate is negative.

B

Which of the following statements about plant physiology are TRUE? I. Intact, functioning roots are required in order for transpiration to occur within a plant. II. Guard cells open when solutes, such as K+ and Cl-, are pumped into the cells. III. The CAM photosynthesis pathway differs from the C3 photosynthetic pathway in that CAM does not utilize the Calvin Cycle. A. I only B. II only C. I and II D. II and III E. I-III

B

Why is it harder to make ethanol from cellulose compared to starch? I. Starch is more structurally complex than cellulose. II. Starch is easier to break down than cellulose III. Because starch is made of glucose molecules linked together. IV. Enzymes that breakdown starch are easier to use in industrial settings and more abundant. A. II only B. II and IV C. II-IV D. I and IV E. I - IV

B

A graph shows that as the number of breeding females in a sparrow population increases, the number of young fledged per female decreases. What happens to sparrow birth rates as sparrow population size increases? A. Birth rates increase as population size increases B. Birth rates decrease as population size increases. C. Birth rate are not dependent on population size. Explain your answer.

B *Resources* - competition for food, so decreased survival of baby birds *Habitat* - competition for nesting areas, pairs defend territories *Death rates* - disease is more likely to spread because offspring are closer together, possibly higher predation rates

Plants require a great deal of water because water is consumed in the process of photosynthesis. A. true B. false

B (Plants need water because they lose lots of water via transpiration when the stomata opens)

Root cells produce oxygen through photosynthesis. A. True B. False

B (Requires sunlight)

You are growing C3 and C4 plants in normal (21%) and low (1%) O2 air, under both warm well-lit conditions and cool shady conditions and you measure rates of photosynthesis. You find that, in general, the C3 plants have higher net rates energy production compared to C4 plants in: A. Warm-sunny conditions at 1% O2 and cool shade at 21% O2 B. Cool shade under 21% and 1% O2 , and in warm-sunny conditions at 1% O2 C. Cool shade at 21% O2 and warm-sunny conditions at 21% O2 D. Warm sunny conditions at 21% and 1% O2 , and cool shade at 21% O2

B (because there are more steps for C4 plants, photosynthesis for C4 plants requires more energy)

Songbirds in the tropics have an average clutch size of 2-3 eggs Songbirds at higher latitudes (like in North America) have an average clutch size of 4-10 eggs. Songbirds at higher latitudes have higher fitness that songbirds in the topics. A. True B. False

B - Can't make claims about fitness because fitness depends on environment: They may be maximizing fitness for their different environments (Warmer temps = more mating, lower temps = less mating)

C4 plants are ________ in shady habitats because C4 photosynthesis has ______________ than the C3 pathway. A.common; lower ATP requirements B.common; higher ATP requirements C.rare; lower ATP requirements D.rare; higher ATP requirements

D

Grapes growing on a vine shrink during the day and only grow in size at night. You decide to do an experiment where you freeze the stem supplying a cluster of grapes with a copper clamp cooled to just a few degrees below zero and then thaw it. Freezing the large-diameter xylem vessels of a vine leads to the formation of air bubbles (cavitation), but has no effect on phloem transport - so this treatment prevents xylem but not phloem transport. What would you expect to see in the experimental grape cluster after this treatment? A. Grape size continues to shrink during the day and increase at night. B. Grape size increases during the day and increases slightly or stays constant at night. C. The grapes dry out and shrivel due to freeze-thaw cavitation. D. Grape size decreases during the day and increases slightly or stays constant at night.

B - Grape shrunk during day due to transpiration in the xylem. However, phloem transport is still occurring, so they gain sugar (and some water due to sap). Because they're already increasing in size during day, they don't need to increase in size at night anymore which is why the grapes only increase slightly in size/stay constant

Will a population exhibiting exponential growth grow faster if there are 20 individuals initially in the population or 2000? Assume that the per capita growth rate is the same for both populations. A. A population with 20 individuals will grow faster. B. A population with 2000 individuals will grow faster. C. Both populations will grow at the same rate.

B - Per capita growth rate is r which is the same for both populations, so if more individuals are reproducing the population will grow faster

Corn is a C4 plant. Which of the following correctly describes a path that a carbon molecule could take that moves it from being in the atmosphere to become glucose in a leaf and the path includes all the relevant plant structures. A. CO2 in the atmosphere, through stomata, CO2 in mesophyll cell, 4-carbon sugar in mesophyll cells, CO2 released from 4-carbon sugar, photosynthesis, glucose. B. CO2 in the atmosphere, CO2 in mesophyll cell, 4-carbon sugar in mesophyll cells, transported to bundle sheath cells, CO2 released from 4-carbon sugar, photosynthesis, glucose. C. CO2 in the atmosphere, through stomata, CO2 in mesophyll cell, 4-carbon sugar in mesophyll cells, transported to bundle sheath cells, CO2 released from 4-carbon sugar, photosynthesis, glucose. D. CO2 in the atmosphere, through stomata, CO2 in mesophyll cell, 3-carbon sugar in mesophyll cells, transported to bundle sheath cells, CO2 released from 3-carbon sugar, photosynthesis, glucose. E. CO2 in the atmosphere, through stomata, CO2 in bundle sheath cell, 4-carbon sugar in, transported to mesophyll cell, CO2 released from 4-carbon sugar, photosynthesis, glucose.

C

When the forces pulling water through the xylem are large, the risk of vessel collapse is _______ and the chance that an air bubble will be spread from one vessel to another is _____. A. increased; decreased B. decreased; increased C. increased; increased D. decreased; decreased

C

Which of the following is a difference you would expect to see between roots and leaves? A. Only leaves have phloem and only roots have xylem. B. Roots cells have cell walls, while leaf cells lack cells walls. C. A waxy cuticle covers leaves, but there is no waxy cuticle in roots. D. Leaves have vasculature tissue, but roots do not. E. More than one of the above it correct.

C

Which of the following processes moves water xylem vessels from the roots to the tree tops? A. Active transport of ions into vascular tissue. B. Active transport of sucrose into phloem sieve tubes. C. Evaporation of water through stomata. D.Water pressure building up in roots. E. Osmosis in roots.

C

You are growing C3 and C4 plants in normal (21%) and low (1%) O2 air, under both warm sunny conditions and cool shady conditions and you measure rates of photosynthesis. *Which treatment/s will have the highest rates of photosynthesis for the C4 plant?* I. Sunny/warm - low oxygen II. Sunny warm - normal oxygen III. Cool/shady - low oxygen IV. Cool/shady - normal oxygen A. I only B. II only C. I and II D. I and III E. III and IV

C

You are studying the turgor pressure (water pressure) at two different ends of a phloem sieve tube. One end of the sieve tube is located within a mature leaf, and the other end is located within the roots. When comparing the turgor pressure within the sieve tube at these two locations, what would you expect to find? A. The turgor pressure will be the same at the leaf and root ends. B.The turgor pressure will be greater at the root end. C. The turgor pressure will be greater at the leaf end. D. Turgor pressure will not exist at either location.

C

Grapes are C3 plants. You observe that grapes growing on a vine shrink during the day and only grow in size at night. Which of the following explains the changes in grape size? I. Grapes are a sugar sink at night, but a sugar source during the day. II. Transpiration during the day. III. Phloem transport during the day and night. IV. Stomata are closed during the day. A. II only B. III and IV C. II and III D. I, II, III E. I and II

C I: Leaves are the source II: We know that the grapes shrink during the day, meaning that transpiration is occurring in the xylem during the day III: Phloem transport occurs both during the day and night IV: Stomata are open during the day

Which of the following would inhibit the movement of sap through phloem in a C3 plant? I. Prevent photosynthesis in source cells II. Make the walls of phloem cells elastic III. Nighttime A. I B. II C. I, II D.II, III E. I-III

C I: nothing to move into cell if photosynthesis doesn't occur II: Elastic = makes cells expand when water flows in and cells get bigger; water will push against the cell wall III: plants are still active at night, still moving stuff around (needs ATP from cellular respiration to load sugar into phloem)

Measurements of the diameter of a plant stem during a long drought show a gradual decrease in diameter over time and then a sudden return to almost its original diameter, even as the drought continues. Which of the following hypotheses is the most likely explanation for the increase in stem diameter? A. Water flow from the soil increased due to the use of ATP to drive the selective uptake of nutrients, leading to water uptake by osmosis. B. Water flow from the soil increased due to greater stomatal opening. C. Air entry and cavitation released the tension in the stem xylem. D. Redistribution of water from the leaves swelled the stem xylem.

C (Air bubble causes the tension to release, and thus the stem snaps back into place)

C4 plants have a __________ rate of photosynthesis in sunny, warm/low oxygen conditions compared to sunny, warm/normal oxygen conditions. Explain your answer. A. Higher B. Lower C. The same

C (C4 plants have adaptations (bundle sheath cells→ increase CO2 around rubisco) to prevent photorespiration, so oxygen levels don't have much effect on C4 plants rates of photosynthesis.)

In all of the following conditions, except one, C3 plants have higher rates of photosynthesis than C4 plants. Which of the following is the exception, where C3 plants have lower rates of photosynthesis than C4? A. Cool shade, normal oxygen B. Cool shade, low oxygen C. Warm sunny, normal oxygen D. Warm sunny, low oxygen

C (Cool shade is a disadvantage for C4 plants because they are using extra energy (ATP) that they don't need to be using)

You are examine phloem transport in plants in Massachusetts. When would phloem transport rates be highest? A. From 1960-1990. B. From 2000-2010. C. In all years from April-September. D. In all years from October-March. E. April-September in the years 1960-1990.

C (Higher photosynthesis rates)

How would subjecting a CAM plant at night to normal daytime temperatures affect its water use efficiency (CO2 captured /H2O lost)? A.CO2 capture would increase, due to a temperature-induced increase in PEP carboxylase activity, which is enough to increase water use efficiency. B. CO2 capture would decrease due to temperature inhibition of rubisco, which would decrease water use efficiency. C. Water use efficiency would decrease due to an increasing concentration gradient for diffusion of water out of the leaf at night. D.Water use efficiency would increase due to more rapid diffusion of CO2 in warmer temperatures.

C - Hot at night = more water evaporation OUT of the plate because stomata are open

Which of the following conditions will make cavitation more likely? I. Wider xylem vessels II. Narrower xylem vessels III. Dry conditions IV. Windy conditions A. I and III B. II and III C. I, III, and IV D. II, III, and IV

C - Windy day = moving water molecules away from plant faster, dries out plant leading to cavitation

You are working for the New England Fishery Management Council which works to conserve and manage fishery resources from three to 200 miles off the coasts of Maine, New Hampshire, Massachusetts, Rhode Island, and Connecticut. You need to develop a management plan for monkfish (aka goosefish) that includes sustainable harvesting (fishing) for monkfish. Observations show that the monkfish population is exhibiting logistic growth. Which of the following harvesting recommendations would best balance conservation and commercial fishing interests? A. Allow the population to reach carrying capacity with minimal harvesting. B. Only harvest monkfish when the population exceeds its carrying capacity. C. Allow harvesting until the population reaches the populations size that is half its carrying capacity. D. Allow harvesting until the population is very small so that it can then have "exponential-like" population growth rate and recovery quickly.

C -Half of K: there is still a large enough population of fish where the fish population can still grow rapidly.

Compare and contrast these 3 photosynthetic pathways.

C3: All steps of carbon fixation in mesophyll cells. No adaptations to avoid photorespiration or water loss. C4: Initial carbon fixation (to C4 sugar) in mesophyll and then Calvin Cycle in bundle sheath cells. Avoids photorespiration CAM: Stomata open at night (bring in CO2 at night) and store carbon as a 4 carbon sugar. Calvin cycle during the day. Increase water use efficiency. Avoid photorespiration.

_____ plants are able to reduce photorespiration by creating a _____ concentration of _____ in bundle sheath cells where the Calvin cycle occurs.

C4; high; CO2

At sunset, the researchers sever (cut) the phloem sieve tubes, but not the xylem, in the vascular bundles leading to one section of a Hylocereus undatus plant (CAM). How will cutting the phloem affect CO2 uptake and transpiration in the section of the leaf indicated below for the next 24 hours? Describe any changes to CO2 uptake and transpiration that occur, indicate time of day.

CO2 uptake and transpiration will still occur throughout the first night. CO2 uptake and transpiration will stop at sunrise and not occur during the day, since this is a CAM plant. - The stomata will open during the first night even though the phloem are cut because this is a CAM plant. - Glucose will not be made by the Calvin cycle until daytime -- so this CO2 will be stored in a vacuole as a C4 sugar. - Because the stomata re open during the second night, transpiration will occur still - The stomata will close during the second night (CAM plant and transpiration and CO2 uptake will stop) since there is an accumulation of glucose in the mesophyll cell (no where to unload that sugar; plant is signaled to stop photosynthesis).

How will low (1%) O2 levels impact *C4 plants*? A. Low O2 levels will reduce rates of photosynthesis because photosynthesis requires oxygen. B. Low O2 levels will increase rates of photosynthesis because rates of photorespiration will decrease. C. Low O2 levels will increase rates of photosynthesis because rubisco will have a higher affinity for CO2. D. Low O2 levels will not have much of an impact on rates of photosynthesis because C4 plants increase concentrations of CO2 around rubisco.

D

On a hot summer day, a large oak tree might move around 200 liters of water from the roots to the leaves, 30 meters above the forest floor. This process is called _________________. A. Cavitation B. Photorespiration C. Osmosis D. Transpiration

D

R Pearcy studied the ability of A. lentiformis, a desert shrub found in Death Valley. They grew multiple genetically identical A. lentiformis seedlings from cuttings. Half of the seedlings were grown in hot conditions (43°C daytime temperature) and half were grown in cold conditions (23° C daytime temperature) for two weeks. They then measured the photosynthetic rates of the two sets of plants across a range of temperatures. If A. lentiformis exhibits adaptive phenotypic plasticity in regards to photosynthetic rates then you would expect: A) That the temperature that the plants were grown in would have no impact on photosynthetic rates. B) The plants grown in hot conditions to have higher rates of photosynthesis in hot conditions. C) The plants grown in hot conditions to have higher rates of photosynthesis in cold conditions. D) The plants grown in hot and cold conditions both have higher rates of photosynthesis in hot conditions

D

What happens to population growth rate when N is equal to K? A. dN/dt will be negative B. dN/dt will be positive, but very small. C. The population is extinct. D. dN/dt=0

D

What happens to population growth rate when N is greater than K? A. Population growth rate increases. B. Population growth rate decreases. C. Population growth rate is equal to zero. D. Population growth rate is negative.

D

Which of the following are classified as land plants, but not as vascular plants? A. Gymnosperms B. Angiosperms C. Ferns D. Mosses E. Algae

D

Which of the following best describes phloem transport from actively photosynthetic leaves? A. Leaves are sugar sinks, sugar is loaded into the phloem in leaves and water them enters the phloem via osmosis. B. Leaves are sugar sinks, sugar is loaded into the phloem in leaves and water them exits the phloem via osmosis. C. Leaves are sugar sources, sugar is loaded into the phloem in leaves and water them exits the phloem via osmosis. D. Leaves are sugar sources, sugar is loaded into the phloem in leaves and water them enters the phloem via osmosis.

D

Which of the following best explains why rates of photosynthesis decline when leaves wilt? A. Wilted mesophyll cells are incapable of photosynthesis. B. CO2 accumulated in the leaves and inhibits photosynthesis. C. There is not enough water for the light reactions of photosynthesis. D. Stomata close.

D

You are growing C3 and C4 plants in normal (21%) and low (1%) O2 air, under both warm sunny conditions and cool shady conditions and you measure rates of photosynthesis. *Which treatments will have the highest rates of photosynthesis for the C3 plant?* I. Sunny/warm - low oxygen II. Sunny warm - normal oxygen III. Cool/shady - low oxygen IV. Cool/shady - normal oxygen A. I only B. II only C. I and II D. I and III E. III and IV

D

Which of the following adaptation would help a plant *AVOID* the loss of water transport by cavitation: I. Many xylem vessels in parallel. II. Plants actively pump air in xylem vessels. III. Wide xylem vessels. IV. Narrower xylem vessels. A. I only B. III only C. I and III D.I and IV E. II and IV

D *I: If one has cavitation, another can continue its job* II: This would lead to cavitation III: Wider = more space for air bubbles, even though more water being brought in *IV: Water molecules have better opportunity to stick to sides, even though less water is being brought in*

Sugar is loaded into the phloem at the source and taken out at the sink. When sugar goes into the phloem, it draws more water into the phloem, which has rigid walls. Which of the following best explains the movement of water and sugar from leaf to growing root? A.The sugar water is heavier and so sinks to the roots B. The sugar diffuses so that there is an even concentration C. The walls of the phloem expand then contract, forcing the sugar water down. D. The sugar loaded into the phloem draws in more water which creates pressure, forcing the sugar water towards the sinks. E.The sink adds sugar to the phloem effectively sucking more water towards it.

D (Osmosis!)

You are a marine biologist studying crustose coralline algae, which makes a calcium carbon crust. What would be the likely impact of ocean acidification on this organism? A. Increase K and increase population growth rates. B. Increase K and decrease population growth rates. C. Decrease population growth rates, no change in K. D. Decrease K and decrease population growth rates. E. Decrease K, but increase population growth rates.

D - pH is lower, environment cannot support as many algae as it did before so K decreases as well

Which of the following is not a correct combination of plant tissue and function in a leaf? A.epidermis: covering of leaf surface B. mesophyll: photosynthetic cells C. veins: vascular tissue D.epidermis: protection E.mesophyll: leaf surface

E

Which of the following statements is true regarding ATP use in plant transport? I. Water movement in xylem does not require ATP. II. Loading sugar into phloem requires ATP. III. Movement of mineral nutrients from the soil into plant roots requires ATP. A. I only B. II only C. I and III D. II and III E. I, II and III

E

Soybeans utilizes C3 photosynthesis. Researchers sever (cut) the phloem sieve tubes, but not the xylem, in the vascular bundles leading to one section of the plant. Which of the following statements are true about the soybean leaves in the section of the plant affected by the phloem cut? I. Transpiration and CO2 uptake happen concurrently in the soybean leaves. II. If a mesophyll cell has no place to upload sugar, then this will signal for the stomata to close. III. The leaves are initially a source for sugar/glucose. A. I only B. II only C. I and II D. II and III E. I, II, and III

E I: Stomata is entry way for CO2 and exit way for water II: Too much sugar in the phloem can cause a backlog, signaling the plant to stop photosynthesis in that particular area III. This is true

Which of the following statements are true? I. All plants contain xylem and phloem. II. There are some species of vascular plants than can survive without xylem. III. If a plant part is a sink for sucrose, than that part will be a sucrose sink for the plant's entire lifetime. IV. Transpiration occurs in C3 and C4 plants, but not CAM because their stomata are only open at night. A. I only B. II and IV C. I-III D. III and IV E. All the statements are false.

E I: Remember, bryophytes aren't vascular and don't contain xylem or phloem! II: All vascular plants require xylem and phloem III: It changes IV: CAM plants also undergo transpiration

True or false? Having multiple, wide xylem running in parallel reduces the risk of cavitation.

False - need *narrow* xylem so that water molecules adhere to the sides of the xylem better and keeps the chain of water molecule together

Which of the following will allow guard cells to change from closed to open? Select all that apply. I. Pump solutes, like ions or glucose, into the cytosol of guard cells. II. Pump solutes, like ions or glucose, out of the cytosol of guard cells. III. Increase guard cell internal sugar concentration. IV. Decrease guard cell internal sugar concentration.

I and III

If the transpiration rate increases, then water absorption by the root ________.

Increases

How has irrigation water affected soil fertility?

Irrigation water often contains dissolved salts. - Plants exclude salts (Na+, Cl-, Mg2+, etc). - So salt concentrations build up in the soil. - Eventually reducing soil fertility.

Why will C3 plants will have the highest rates of photosynthesis under the sunny-warm, low oxygen conditions?

Photosynthesis requires sunlight

Predict the outcome of an experiment: You grow one plant in nutrient-rich soil. You grow another plant in nutrient-poor soil. How might you expect their root hairs to be different?

Plants in nutrient-poor soil will have more root hairs because it needs to increase surface area in multiple directions

When water is scarce/roots are damaged, the plant needs to __________ their transpiration rate by...

Reduce; closing some of its stomata

Explain why there is a latitudinal gradient in the percentage of C4 grasses - your answer should include connections to C4 plant physiology and temperature.

There are more C4 grasses at lower latitudes because it is warmer at lower latitudes. Photorespiration increase as temperature increases. C4 plants increase CO2 concentration in bundle sheath cells and this avoids photorespiration.

Where is pressure the greatest in xylem and phloem?

Xylem - at the top of the plant because water is being pulled up and out of the plant through the stomata Phloem - where high sugar concentration is, allowing the sugar to be pushed into the correct direction (toward sink)

Rubisco is the most abundant protein on the planet, but it is not a "perfect" enzyme (remember natural selection does not lead to perfect). During photosynthesis, rubisco uses _____________ as a substrate, but during photorespiration, rubisco uses _____________ . A.CO2, O2 B. O2, CO2 C.H2O, O2 D.H2O, CO2 E.CO2, H2O

a

The status of a tissue as source or sink may change depending on the growth and development of that tissue, as well as tissues located elsewhere in the plant. a. true b. false

a

Which of the following best explains why flooding is harmful to many plant species? Select one: a. Water-logged soils have little O2. b. Flooding reduces soil pH. c. Water-logged soils have little CO2. d. Flooding impairs the function of symbiotic bacteria.

a

describe what happens to population growth when ( 1 - N/K ) is the following values: a. 0.9 b. 0.02 c. 0 d. -0.1

a. close to 1, so growth wouldn't change much b. multiplying by 0.02 would shrink exponential growth c. this is at carrying capacity, so births = deaths d. beyond carrying capacity, so population growth is negative

Assuming the stomata are open to the same degree, the rate of transpiration should _____ on a rainy day compared with a sunny day, because the relative size of the H2O concentration gradient from the inside to the outside of the leaf would _____. a. decline; increase b. decline; decrease c. remain the same; not change d. increase; decrease e. increase; increase

b

Under what circumstances can leaves be sinks for carbohydrates delivered by phloem? a. when they are very old b. when they are very young c. when the roots contain more carbohydrates than they need d. when there are no reproductive organs that have first priority for carbohydrates

b

Which of the following statements about exponential growth is TRUE? a. In the exponential growth model, the per capita growth rate (r) gradually increases over time. b. In the exponential growth model, the per capita growth rate doesn't change over time. c. In the exponential growth model, population growth rate is constant. d. In the exponential growth model, a population that initially has a small population size will grow at the same rate as a population that initially has a large population size.

b

A population of 20 squirrels, with 10 males and 10 females, colonizes a new area with no predators and enough plant species to support a squirrel population of 200 individuals. Each year, a female produces 2 offspring, one male and one female, that survive to reproduce. Within the first 2 years in the new area, the growth curve for this squirrel population will show: a. logistic growth because the squirrel population will reach maximum population size immediately after colonization. b. logistic growth because there is a carrying capacity in the newly colonized area. c. exponential growth because the colonizing population size is far below the carrying capacity. d. exponential growth because only a few individuals will have offspring.

c

If having large numbers of offspring results in high fitness, then which of the following best explains why all species don't produce a very large numbers of offspring? a. In some species, the number of eggs a female will have in her lifetime is finite, developing before she reaches reproductive age. b. A parent, regardless of species, would die before they could raise all of the offspring they could produce. c. Reproduction is limited by the amount of energy that can be devoted to reproduction in any one season. d. For most species, mating is limited to a specific time of the year and this limits the number of offspring.

c

In all of the following conditions, except one, C3 plants have higher rates of photosynthesis than C4 plants. Which of the following is the exception, where C3 plants have lower rates of photosynthesis than C4? a. Cool shade, normal oxygen b. Cool shade, low oxygen c. Warm sunny, normal oxygen d. Warm sunny, low oxygen

c - C3 plants would undergo photorespiration

In vascular plants, water transport works only if: a. xylem and phloem are in close proximity. b. roots are able to generate turgor pressure. c. the xylem has access to a constant source of ATP. d. the water column is continuous between leaves and soil

d

Which of the statements is true of transport in phloem? a. It occurs from sink to source. b. It only occurs from leaves to roots. c. It moves materials down the plant body. d. It is driven by turgor pressure. e. It is usually a passive process.

d

Soybeans, Glycine max, utilizes C3 photosynthesis. Researchers sever (cut) the phloem sieve tubes, but not the xylem, in the vascular bundles leading to one section of the plant (see the diagram below). Which of the following best describes how cutting the phloem will affect CO2 uptake and transpiration in that section of the plant for the next 12 hours? Assume the experiment began at noon, the plant is well watered and it is growing in a sunny location. a. Transpiration would immediately stop, CO2 uptake would continue until sunset and then it would stop. b. CO2 uptake would immediately stop, transpiration would continue until sunset and then it would stop. c. There would be no CO2 uptake or transpiration until sunset, and then both would occur. d. Both CO2 uptake and transpiration would continue for 1-2 hours and then both would stop e. Both CO2 uptake and transpiration would continue until sunset and then both would stop.

d Transpiration and CO2 uptake occur simultaneously - when the stomata are open (*so you can't separate transpiration and CO2 uptake!*). If the phloem are cut, then the leaves that are in that section of the plant will not be able to load much more sugar into the phloem sieve tubes (since phloem sap cannot be transported out of the leaves). This will disrupt the source-sink relationship in the leaves. The accumulation of sugar in the leaves will signal for the stomata to close.

Guard cells can actively increase their volume, and thus size, by: Select one: a. increasing the amount of CO2 in the cells. b. reducing the amount of solutes such as K+ and Cl-. c. increasing the amount of water in the cells without changing solute concentration. d. decreasing the amount of water in the cells without changing solute concentration. e. increasing the amount of solutes such as K+ and Cl-.

e