Chapter 36

Question 1

A plant organ in which sugar is being produced by either photosynthesis or the breakdown of starch. Mature leaves are the primary sugar sources of plants.

Answer 1

sugar source

Question 2

A mutualistic association of plant roots and fungus.

Answer 2

mycorrhiza

Question 3

The leading explanation of the ascent of xylem sap. It states that transpiration exerts pull on xylem sap, putting the sap under negative pressure, or tension, and that the cohesion of water molecules transmits this pull along the entire length of the xylem from shoots to roots.

Answer 3

cohesion-tension hypothesis

Question 4

The exudation of water droplets from leaves, caused by root pressure in certain plants.

Answer 4

guttation

Question 5

A plant organ that is a net consumer or storer of sugar. Growing roots, shoot tips, stems, and fruits are examples of sugar sinks supplied by phloem.

Answer 5

sugar sink

Question 6

A component of water potential that is proportional to the molarity of a solution and that measures the effect of solutes on the direction of water movement; also called osmotic potential, it can be either zero or negative.

Answer 6

solute potential

Question 7

The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure.

Answer 7

water potential

Question 8

(1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle, when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants.

Answer 8

translocation

Question 9

Swollen or distended, as in plant cells. (A walled cell becomes turgid if it has a lower water potential than its surroundings, resulting in entry of water.)

Answer 9

turgid

Question 10

The evaporative loss of water from a plant.

Answer 10

transpiration

Question 11

Vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from the roots to the rest of the plant.

Answer 11

xylem

Question 12

The pattern of leaf attachment to the stem of a plant.

Answer 12

phyllotaxy

Question 13

Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant.

Answer 13

phloem

Question 14

A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment.

Answer 14

plasmolysis

Question 15

A water-impermeable ring of wax in the endodermal cells of plants that blocks the passive flow of water and solutes into the stele by way of cell walls.

Answer 15

Casparian strip

Question 16

A component of water potential that consists of the physical pressure on a solution, which can be positive, zero, or negative.

Answer 16

pressure potential

Question 17

The drooping of leaves and stems as a result of plant cells becoming flaccid.

Answer 17

wilting

Question 18

The living part of a plant cell, which also includes the plasma membrane.

Answer 18

protoplast

Question 19

In plants, the continuum of cytoplasm connected by plasmodesmata between cells.

Answer 19

symplast

Question 20

A plant hormone that slows growth, often antagonizing the actions of growth hormones. Two of its many effects are to promote seed dormancy and facilitate drought tolerance.

Answer 20

abscisic acid (ABA)

Question 21

A plant adapted to an arid climate.

Answer 21

xerophyte

Question 22

Limp. Lacking turgor (stiffness or firmness), as in a plant cell in surroundings where there is a tendency for water to leave the cell. (A walled cell becomes flaccid if it has a higher water potential than its surroundings, resulting in the loss of water.)

Answer 22

flaccid

Question 23

Pressure exerted in the roots of plants as the result of osmosis, causing exudation from cut stems and guttation of water from leaves.

Answer 23

root pressure

Question 24

The force directed against a plant cell wall after the influx of water and swelling of the cell due to osmosis.

Answer 24

turgor pressure

Question 25

A physiological cycle of about 24 hours that persists even in the absence of external cues.

Answer 25

circadian rhythm

Question 26

The diffusion of free water across a selectively permeable membrane.

Answer 26

osmosis

Question 27

The movement of a fluid due to a difference in pressure between two locations.

Answer 27

bulk flow

Question 28

The dilute solution of water and minerals carried through vessels and tracheids.

Answer 28

xylem sap

Question 29

A unit of pressure equivalent to about 10 atmospheres of pressure.

Answer 29

megapascal (MPa)

Question 30

The uppermost layer of vegetation in a terrestrial biome.

Answer 30

canopy

Question 31

A channel protein in a cellular membrane that specifically facilitates osmosis, the diffusion of free water across the membrane.

Answer 31

aquaporin

Question 32

The sugar-rich solution carried through a plant’s sieve tubes

Answer 32

phloem sap