Deck 9: Water in Plants

Question 1

Pressure that develops within a living cell as a result of water entering the cell is called

A) turgor.
B) osmosis.
C) plasmolysis.
D) transpiration.
E) water potential.

Answer 1

A

Question 2

Molecules that, due to their symmetry, have slightly different electric charges at each end are said to be

A) polar.
B) colloidal.
C) unbalanced.
D) electrocharged.
E) covalent.

Answer 2

A

Question 3

The movement of molecules from a region of high concentration to a region of low concentration is

A) osmosis.
B) movement against the concentration gradient.
C) Brownian motion.
D) diffusion.
E) only common in gases such as oxygen.

Answer 3

D

Question 4

When starch and cellulose molecules are exposed to water, they develop electrical charges and form ________.

A) ionic bonds with water
B) an electric current
C) covalent bonds with water
D) static electricity charges
E) hydrogen bonds with water

Question 5

The pressure required to prevent osmosis from taking place is referred to as:

A) water potential
B) osmotic potential
C) pressure potential
D) turgor pressure
E) None of these answers are correct.

Question 6

When an entire plant wilts, it is due to ________.

A) the lack of mineral nutrients
B) the decrease in salt concentration
C) the loss of turgor pressure in leaf and stem cells similar to that of plasmolysis
D) excessive turgor pressure
E) a decrease in cellulose and lignin strengthening cell walls

Question 7

Active transport in plants apparently involves an enzyme complex that forms a/an ________.

A) channel through the cell membrane
B) passive transport system
C) energy-free transport system
D) proton pump
E) sodium/potassium pump

Question 8

If the concentration of solutes outside the plant cell is greater than the concentration on the inside, water will

A) move into the cell.
B) move in both directions equally.
C) move against a concentration gradient.
D) move out of the cell.
E) None of these answers are correct.

Question 9

Pressure sufficient to prevent the rise of fluid in an osmometer tube, when applied to the top of the tube, is called

A) pressure diffusion.
B) turgor pressure.
C) osmotic pressure.
D) pressure potential.
E) water potential.

Question 10

Substances are absorbed and retained against a concentration gradient, through the expenditure of energy, by ________.

A) active transport
B) passive transport
C) imbibition
D) osmosis
E) None of these answers are correct.

Question 11

Imbibition is responsible for ________.

A) plants wilting on sunny days
B) breaking open the seed coat of germinating seeds
C) osmosis
D) turgor pressure in cells
E) expansion of the vacuole inside the living cell

Question 12

When a solute is dissolved in water, the ________ of the water is lowered.

A) osmotic pressure.
B) pressure potential
C) turgor pressure
D) osmotic potential
E) gravity potential

Question 13

The cohesion of water molecules and their adhesion to the walls of narrow tubes that results in water rising in the tubes is called

A) imbibition.
B) capillarity.
C) active transport.
D) guttation.
E) transpiration pull.

Question 14

Water potential is calculated by ________.

A) subtracting turgor pressure from osmotic potential
B) calculating the rate of diffusion of water molecules in dry soil
C) combining osmotic potential and pressure potential of a plant cell
D) determining the rate of plasmolysis
E) None of these answers are correct.

Question 15

________ occurs when water forms hydrogen bonds with large organic molecules such as cellulose in living or dead tissues.

A) Imbibition
B) Turgor pressure
C) Plasmolysis
D) Active transport
E) Guttation

Question 16

Which of the following is NOT involved in guard cell regulation of stomata opening?

A) photosynthesis
B) active transport
C) osmosis
D) imbibition
E) accumulation of potassium ions

Question 17

Liquid water is forced out of the leaf when leaf pores are closed at night in a process called

A) transpiration.
B) translocation.
C) evaporation.
D) guttation.
E) diffusion.

Question 18

Which of the following plays a role in plasmolysis?

A) water potential.
B) vacuole.
C) plasma membrane.
D) protoplasm.
E) All of these answers are correct.

Question 19

Most of the water that enters a plant via the roots leaves the same plant by the process of

A) guttation.
B) plasmolysis.
C) osmosis.
D) root pressure.
E) transpiration.

Question 20

Osmosis is a special kind of diffusion in which water molecules

A) move across a selectively permeable membrane.
B) move from a region of lower concentration to a region of higher concentration.
C) exhibit random kinetic motion.
D) move through suberin.
E) Both move across a selectively permeable membrane and move from a region of lower concentration to a region of higher concentration are correct.

Question 21

Plants that have their stomata elevated above the surface include

A) a few tropical plants.
B) pines.
C) cacti.
D) water lilies.
E) most grasses.

Question 22

Many studies leading to our present knowledge of translocation of food in plants utilized radioactive tracers and

A) cane sugar (sucrose).
B) aphids.
C) osmometers.
D) fungi.
E) algae.

Question 23

At present the most widely accepted theory for movement of sugars in the phloem is called the

A) pressure-flow hypothesis.
B) cohesion-tension-transpiration theory.
C) translocation theory.
D) water-potential theory.
E) imbibition-guttation hypothesis.

Question 24

When humidity is high

A) transpiration rates increase.
B) transpiration rates decrease.
C) transpiration ceases altogether.
D) leaves absorb moisture from the air.
E) stomata open wider.

Question 25

Relatively uniform loss of color in leaves, occurring first on the older ones, is usually a sign of deficiency of which of the following?

A) potassium
B) iron
C) nitrogen
D) magnesium
E) boron

Question 26

The process of loading and transport of food through the phloem tissue involves which of the following factors?

A) osmosis
B) active transport
C) mass flow
D) differences in water potential
E) All of these are involved in phloem transport.

Question 27

The early scientist who suggested that cells surrounding xylem vessels perform a pumping action that propels water through a plant was

A) Nehemiah Grew.
B) J. B. van Helmont.
C) Frits Went.
D) Joshua Doolittle.
E) Hans Krebs.

Question 28

The rise of water in plants is presently most satisfactorily explained by

A) the pressure-flow hypothesis.
B) active transport.
C) imbibition.
D) bulk flow.
E) the cohesion-tension theory.

Question 29

An area within a plant where food is utilized is called a

A) food-storage region.
B) translocation region.
C) sink.
D) sub-stomatal chamber.
E) tension column.

Question 30

Plants obtain most of their mineral nutrients ________.

A) from minerals dissolved in water entering the root system
B) from dust in the air
C) when they enter the plant through the stomata in the leaves
D) from fertilizer
E) as a solid

Question 31

Which is an essential trace element in plants?

A) iron
B) phosphorus
C) copper
D) sulfur
E) nitrogen

Question 32

All essential macro- and microelements exist as part of organic molecules in the plant except

A) potassium.
B) phosphorus.
C) nitrogen.
D) hydrogen.
E) carbon.

Question 33

Organic molecules produced in photosynthesis are mainly transported in the form of ________.

A) glucose
B) starch
C) carbon dioxide
D) cellulose
E) sucrose

Question 34

The direction of movement of food molecules in plants is ________.

A) only from the top of the plant to the root system
B) from the roots to the shoot system
C) from sink to source
D) from source to sink
E) None of these answers are correct.

Question 35

In which of the following situations will the rate of transpiration increase, assuming that no other variable changes?

A) an increase in the relative humidity
B) the plant is under water stress
C) the sun has just gone below the horizon (dusk)
D) the stomata are recessed below the surface of the leaf (stomatal crypts)
E) the air temperature increases

Question 36

Approximately how much water typically leaves the plant by transpiration?

A) 90% or more
B) 25% or less
C) 75%
D) 65%
E) 50%

Question 37

Hydathodes are involved directly in which of the following?

A) transpiration
B) imbibition
C) plasmolysis
D) respiration
E) guttation

Question 38

Changes in solute ion concentrations that are involved in the opening and closing of stomata pertain primarily to which of the following?

A) cobalt
B) calcium
C) magnesium
D) potassium
E) iron

Question 39

Which of the following is an essential micronutrient?

A) magnesium
B) sulphur
C) calcium
D) phosphorus
E) manganese

Question 40

Which of the following is NOT one of the nutrients that constitute about 99% of the nutrient total used by plants?

A) nitrogen
B) potassium
C) phosphorus
D) sodium
E) calcium

Question 41

If plasmolyzed cells are placed in fresh water before permanent damage is done, they can become turgid once more.

Question 42

A hydathode is normally located at the tips of a leaf vein.

Question 43

Active transport is the reverse of transpiration.

Question 44

Water and solute molecules never have to enter a cell because they can travel from the epidermis to the root xylem by moving through the cell walls and spaces between cell walls

Question 45

A differentially permeable membrane is one that permits anything up to the size of large molecules to pass through.

Question 46

Some sort of physiological pump is believed to be involved in active transport.

Question 47

Hydroponically grown tomatoes are those that are grown in

A) lakes and streams in arid regions.
B) soil that is watered daily with distilled water.
C) a nutrient solution containing all the essential elements.
D) soil that is watered daily with a macronutrient solution.
E) soil watered with only micronutrients.

Question 48

Most plants have their stomata closed during the day and open at night.

Question 49

All water that passes through a plant leaves the plant via stomata.

Question 50

A state of equilibrium is reached when molecules are evenly distributed in the space available to them.

Question 51

Guttation involves loss of water in liquid form from a leaf.

Question 52

The force created by imbibition of water by wooden structures can be used to split stones.

Question 53

Tension in the leaf xylem is due to the adhesive and cohesive properties of water as well as transpiration.

Question 54

The primary force that enables water to move to the top of very tall trees is root pressure.

Question 55

During plasmolysis water leaves a cell's central vacuole.

Question 56

More than 90% of the water entering most plants passes on through the plant.

Question 57

Osmotic potential is the amount of pressure needed to make water rise in a narrow tube.