Chapter 36: Resource acquisition and transport in vascular plants

Question 1

What kind of molecules are plant primary cell walls composed of?

Answer 1

Cellulose

Question 2

What is the purpose of the central

vacuole?

Answer 2

Reservoir, waste dump, storage

Question 3

plasmodesmata

Answer 3

channels which traverse the cell walls of plant cells, enabling transport and communication between them

Question 4

Apoptosis

Answer 4

Programmed cell death

Question 5

Apoplastic route

Answer 5

through cell walls and extracellular spaces

Question 6

Symplastic route

Answer 6

through the cytosol

Question 7

Transmembrane route

Answer 7

across cell walls

Question 8

Apoplast

Answer 8

everything external to the plasma membrane (cell

walls, extracellular spaces, and the interior of vessel elements and tracheids)

Question 9

Symplast

Answer 9

the cytosol of living cells as well as the plasmodesmata

Question 10

Diffusion

Answer 10

passive movement across the cell membrane (e.g., oxygen)

Question 11

Osmosis

Answer 11

movement of water across the cell membrane

Question 12

Facilitated diffusion

Answer 12

uses transport proteins and is a primary way that glucose is moved across the cell membrane

Question 13

Active transport

Answer 13

moves atoms, ions, or molecules into or out of the cell (endocytosis and exocytosis are examples)

Question 14

Electrochemical gradient

Answer 14

H+ ions and active transport drive solutes across the

cell membrane and against the concentration (e.g., transport of sucrose by phloem)

Question 15

ATP-dependent proton pump moves solutes from…

Answer 15

Low to high concentrations

Question 16

Water potential

Answer 16

combined effects of solute concentration and physical pressure upon water movement in plants

Question 17

Turgor pressure

Answer 17

pressure exerted by the plasma membrane against the cell wall, and the cell wall against the protoplast

Question 18

Protoplast

Answer 18

living part of the plant cell including the plasma membrane

Question 19

What happens if you place a flaccid cell into a

sucrose solution?

Answer 19

Water moves out of the cell and the cell plasmolyzes aka loses water (thus, the water potential inside the cell is more negative)

Question 20

What happens if you place a flaccid cell into pure

water?

Answer 20

Water moves into the cell and the cell becomes turgid (thus, the water potential inside the cell is 0)

Question 21

Selective passage is directed by the…

Answer 21

Endodermis

Question 22

Endodermis

Answer 22

innermost layer of the cortex that surrounds the vascular cylinder

Question 23

The _____ blocks movement of water and solutes in the vascular tissue through the apoplastic route.

Answer 23

casparian strip

Question 24

Transpiration

Answer 24

loss of water from stems and leaves to the surrounding air vapor by diffusion and evaporation

Question 25

Transpirational pull

Answer 25

a force that works against the direction of gravity in plants

Question 26

Spongy mesophyll

Answer 26

increases surface area for gas exchange but also increases the surface area for water loss (This layer is analogous to the alveoli in lungs)

Question 27

Cohesion

Answer 27

linking together of like molecules due to hydrogen bonds

Question 28

Adhesion

Answer 28

the clinging of water molecules to cellulose molecules by means of hydrogen bonds

Question 29

Bulk flow

Answer 29

the process by which proteins with a sorting signal travel to and from different cellular compartments

Question 30

How is bulk flow different from diffusion?

Answer 30

Faster
Moves entire solution
Occurs in hollow dead cells
Driven by pressure potential not solute potential

Question 31

Cavitation

Answer 31

Water conduction can be interrupted when air bubbles form in the tracheids or vessel elements

Question 32

How do plants control water loss?

Answer 32

Guard cells

Question 33

Which is narrower: tracheids or vessel elements?

Answer 33

Tracheids

Question 34

Turgor pressure (opening and closing) is regulated by uptake and loss of _____ ions by the guard cells

Answer 34

Potassium

Question 35

Light ____ K+

Answer 35

Increases

Question 36

CO2 depletion _____ K+

Answer 36

Decreases

Question 37

Circadian rhythm

Answer 37

24 hour cycle (internal clock)

Question 38

Xerophyte

Answer 38

a plant that lives under arid conditions

Question 39

Adaptations for Water Conservation

Answer 39

1. small, thick leaves
2. very thick, waxy cuticle
3. hairs (trichomes) on leaves or recessed stomata
4. drought deciduousness
5. CAM photosynthesis
6. Well-defended against herbivores (e.g., spines, toxic chemicals)

Question 40

CAM photosynthesis

Answer 40

a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions that allows a plant to photosynthesize during the day, but only exchange gases at night

Question 41

Phloem is transported from a ______ to

a _______.

Answer 41

sugar source, sugar sink

Question 42

Sugar source

Answer 42

a plant organ that is a net producer of sugar by photosynthesis or by breakdown of starch

Question 43

Sugar sink

Answer 43

a plant organ that is a net consumer or depository of sugar

Question 44

Translocation

Answer 44

Phloem transports the products of photosynthesis

Question 45

Conduit cells for translocation

Answer 45

sieve-tube elements

Question 46

companion cells

Answer 46

located alongside sieve-tube elements but do not conduct phloem sap
can aid in loading and unloading of sugars from sieve-tube elements

Question 47

Xylem > transpiration >

Answer 47

Negative pressure

Question 48

Phloem > translocation >

Answer 48

Positive pressure

Question 49

What causes phloem to flow from the source to the sink?

Answer 49

Pressure flow