Biology 1040 Ch 32 Mastering Biology

A fertilizer with which of the following nitrogen-phosphorous-potassium ratios would most likely solve the problem of yellowed leaves and stunted growth?

20:0:0

For which continents is land degradation having the least impact on global grain production?

Africa and South America

Which continent likely represents the largest absolute land area experiencing degradation?

Asia

_____ is responsible for the movement of sugars from leaves to taproots; _____ is responsible for the movements of sugar from taproots to leaves.

Bulk flow ... bulk flow

Which of the following is true?

Canker and citrus greening are both caused by bacteria.

What is the physical barrier in the root that regulates the flow of water to xylem via cell walls?

Casparian strip

In roots the _____ forces water and solutes to pass through the plasma membranes of _____ cells before entering the _____.

Casparian strip ... endodermis ... xylem

Which of the following would be the best way to determine if aphids must actively draw phloem sap into their digestive tract or if hydrostatic pressure in the phloem tube could force the sap into them?

Insert mouth parts removed from an aphid, without including the digestive tract, into phloem sap and see if sap keeps flowing through them.

Which of the following options best describes the mechanism that causes a stoma to open?

K+ enters the guard cells and water follows passively, making the cells turgid.

You conduct an experiment to learn more about how water moves within the plant body. You take a common houseplant and cut the stem off about one inch above the soil surface. Water begins collecting at the cut--in the stem stump--as if some force is pushing the water up through the roots and remaining stem. How could you best explain this observation?

Minerals, unable to move up to the leaves, are accumulating in the root, which causes water to rush in due to osmosis.

What are the macronutrients present in most commercial fertilizers?

N, P, and K

Which of the following essential nutrients is most likely to leach from the soil?

NO3-

Root pressure is positive pressure that helps to push water up out of the roots and into the aboveground plant. How is it formed?

Root cells bring mineral nutrients into the root using active transport. This sets up a concentration gradient that draws water into the root by osmosis.

Which of the following describes the correct order in which water moves through a plant and into the atmosphere?

Root, xylem, leaf cells, air space inside leaves, outside air.

Which of the following is a question you should ask Acme about conclusions to be drawn from these data?

Since even the control plots lost metals, do I really need to remediate?

A gardener planted large, healthy flower bulbs in her garden. When spring arrived, green shoots emerged from the bulbs, and some of them, but not all, produced flowers. She decided to dig up a few bulbs that flowered and a few that didn't to see if she could see what the difference was. She was stunned to find that none of the bulbs looked healthy; they all appeared much smaller. What had happened?

The bulbs were a sugar source; sugars from them traveled up the phloem to the aboveground sugar sink.

What is implied by this figure?

The clay particle has a negative charge at its surface.

What is true of the guard cells shown in the right-hand panel of this figure?

These cells are hypotonic to their immediate surroundings.

How do mineral ions get into the xylem cells of a plant root by way of the intracellular route?

They are taken up by root hair cells and transferred from cell to cell via plasmodesmata.

Xylem tissues create a system of very thin pipes that connect plant roots and leaves. Which option best describes the nature and function of xylem tissue?

Xylem is dead tissue. The pipes convey xylem sap from the roots to the leaves. Active transport is not important in moving xylem sap.

Under what circumstances would guard cells look like those in the right panel?

a hot dry day

At a sugar sink, sugar is removed from phloem by _____.

active transport

The sugar "sink" in roots is the result of

active transport of sugars from phloem to root cells.

If you examine the soil profile revealed by a fresh road cut through a grassy rise, which of the following features will you probably find in the B horizon?

an abundance of fine clay but not much organic material

A root hair is _____.

an extension of an individual cell that absorbs water from soil

The water pressure that pushes water and sugar from sugar source to sugar sink is referred to as _____.

bulk flow

How do sugars move from one sieve-tube cell to the next?

by flowing along with water through perforations in the sieve plate

A hot, dry summer will reduce crop yields in part because

carbon dioxide uptake is reduced by the stomata closing to prevent excessive water loss.

Which of the following lists the set of plant macronutrients that make up about 98% of a plant's dry weight?

carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus

Which of these ions is most likely to be leached from the soil?

chlorine ions

You visit a grapefruit tree farm in Florida and see virtually every fruit laying on the ground. Which of the following is the most likely problem?

citrus greening

Micronutrients function in plants mainly as

cofactors in chemical reactions.

Which of the following terms describes water molecules sticking to other water molecules?

cohesion

What keeps the force of gravity from overcoming transpirational pull?

cohesion and adhesion of water molecules

The CEO of Acme Remediation Company is always trying to improve the company's effectiveness by keeping up with current research. Which of the following research topics should have the highest priority for that research?

comparison of plant species' bioaccumulation of metal ions

Mineral nutrients _____.

contribute little to the weight of a plant

Which would provide the best evidence that Acme's phytoremediation really works?

data on heavy metal content of plants grown in normal soil versus soil contaminated with heavy metals

How do cations enter root hairs?

diffusion

The binding of H+ ions to soil particles _____.

displaces mineral cations

Which of the following correctly lists the sequence of structures through which water passes into a root?

epidermis, cortex, endodermis, xylem

What is the main source of energy that moves water upward in the trunk of a tree?

evaporation of water by the sun

The continuum of spaces between cell walls of neighboring cells is the _____ route of water and solute transport from root hairs to xylem.

extracellular

Where do plants get most of their mass?

from carbon dioxide in the atmosphere

The release of CO2 into the soil results in the formation of _____.

hydrogen ions and carbonate ions

As turgor pressure increases in guard cells, the transpiration rate would be expected to _____.

increase

The cytoplasmic continuum connecting neighboring cells is the _____ route of water and solute transport from root hairs to xylem.

intracellular

Soil could be deficient in any of the following nutrients. If you had to supply one of them, which would be needed in the smallest amount?

iron

If a plant's leaves are yellowing, it may be that the plant is deficient in the elements needed to make chlorophyll, which include _____.

magnesium

When you add "plant food" to your potted geraniums, you are actually providing the plant with _____.

minerals

Soil can easily become deficient in _____, because these ions are negatively charged and do not stick to negatively charged soil particles.

nitrate

Water moves into phloem by _____.

osmosis

Which of the following is NOT an essential plant micronutrient?

potassium

Generally speaking, fluids in plants are

pushed through phloem and pulled through xylem.

What process is the source of the CO2 that root hairs release into the soil?

respiration

Sugar moves from leaves into the _____ of _____ by _____.

sieve-tube members ... phloem ... active transport

A student is performing a chemical analysis of xylem sap. This student should not expect to find much _____.

sugar

Which of the following conditions would be most likely to cause stomata to open?

sunrise on a clear morning

When referring to phloem transport, the "sink" in roots is created by _____.

the active transport of sugars from phloem to root cells

The existence of a hydrostatic pressure gradient in phloem tubes can be accounted for by

the loading of sugars into phloem at sources and removal of sugars at sinks.

If a plant is kept in the dark,

the stomata continue their daily rhythm of opening and closing.

Stomata open during the day in response to _____.

the uptake of K+ by guard cells

When considering the source-to-sink model of phloem transport, what plant structures can act as either a source or a sink depending on the season?

tubers and bulbs

The rate of transpiration is expected to be greatest on a _____ day.

warm and dry

In the water relations of vascular plants, the cohesive property of water is most important in the

xylem.