Chapter 30: Transport in Plants

Question 1

Plant roots take up _____ and _________ from the soil

Answer 1

water; minerals

Question 2

Mineral uptake requires transport ___________

Answer 2

proteins

Question 3

Some minerals enter the plant by ____________; others by _____________

Answer 3

facilitated diffusion; active transport

Question 4

Water moves through biological membranes by _________, toward cells with more negative water potential

Answer 4

osmosis

Question 5

Water moves toward solutions with higher __________ concentrations

Answer 5

solute

Question 6

What causes the turgor pressure?

Answer 6

Plant cell walls resist pressure of water moving in

Question 7

Water travels through ______________ layers to reach vascular tissue

Answer 7

several tissue

Question 8

Vascular tissue in a central cylinder called the _________

Answer 8

stele

Question 9

What is the Apoplast?

Answer 9

intercellular spaces and cell walls

Question 10

What is the Symplast?

Answer 10

intracellular spaces (enclosed by membranes)

Question 11

What is the Casparian strip?

Answer 11

waterproof layer between cells of the endodermis

Question 12

In the The casparion strip; Water cannot pass ________ endodermal cells; must go ________

Answer 12

between; through

Question 13

The casparion strip; Allows plant to control which _____________ cross

Answer 13

mineral ions

Question 14

Water and minerals pass from the soil to the xylem via the _______ and _________

Answer 14

apoplast; symplast

Question 15

In the root, water and minerals may pass from the cortex into the stele only via the symplast, because the ______________ blocks the apoplast route at the endodermis

Answer 15

Casparian strip

Question 16

Once water enters stele:
Uptake of water/minerals into ____________

Answer 16

xylem cells

Question 17

In plants, are the xylem cells dead and hollow?

Answer 17

yes

Question 18

Xylem transport is the result of combined effects of ___________, __________, and __________

Answer 18

transpiration, cohesion, and tension

Question 19

What is Transpiration?

Answer 19

evaporation of water from plant parts (especially leaves)

Question 20

What is Cohesion?

Answer 20

tendency of water molecules to “stick” together (hydrogen bonding)

Question 21

What is Tension?

Answer 21

negative pressure (pulls water upward from roots)

Question 22

Evaporation from the leaf (= transpiration) produces _________ in the surface film of water on the mesophyll cells, pulling water and dissolved minerals up the xylem from the root

Answer 22

tension

Question 23

Water evaporation _________ leaves, but a plant cannot afford to lose too much water

Answer 23

cools

Question 24

Transpirational water loss is minimized by the leaves’ ___________

Answer 24

waxy cuticles

Question 25

Stomata open and close via regulated changes in _____________

Answer 25

guard cell pressure

Question 26

Process balances photosynthesis (CO2 uptake) and water loss via __________

Answer 26

transpiration

Question 27

Organic solutes (e.g. sugars, photosynthetic products) are transported in the ________

Answer 27

phloem

Question 28

Products of photosynthesis, and some minerals, are translocated through _________ in the phloem via living sieve tube members

Answer 28

sieve tubes

Question 29

____________ proceeds in any direction in the stem, although in a single sieve tube it goes only one way

Answer 29

Translocation

Question 30

What causes the phloem transport?

Answer 30

translocation

Question 31

Translocation requires a ______________

Answer 31

supply of ATP

Question 32

Translocation in the phloem proceeds in accordance with the _________________

Answer 32

pressure flow model

Question 33

Difference in solute concentration between _________ and __________ allows a difference in pressure potential along sieve tubes, resulting in bulk flow

Answer 33

sources; sinks

Question 34

Companion cells load _________ into sieve-tube members at _________

Answer 34

sucrose; source

Question 35

__________ from xylem follows automatically, due to ________; increases _________ at source

Answer 35

Water; osmosis; turgor pressure

Question 36

Companion cells ________ into sink cells

Answer 36

unload sucrose

Question 37

Water exits sieve tube (back into xylem) via osmosis; __________ at sink

Answer 37

reduces turgor pressure

Question 38

The pressure flow model succeeds because sieve plates are normally open, __________________, and because neighboring cells _____________________________________ in source regions and ________________ regions

Answer 38

allowing bulk flow; load organic solutes into sieve tube members; unload them in sink