Chapter 39: Transportation of Flowering Plants

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1

What does the root system absorb?

Water and minerals

2

What does a shoot system take up?

CO2 from the atmosphere

3

What do photosynthetic cells produce?

Organic compounds

4

What are the two main long-distance transport with conducting tissues?

Xylem and Phloem

5

What are xylem?

Transports water and dissolved minerals

6

What is phloem?

Transports organic substances in a water sap

7

What is simple diffusion?

Movement of molecules through a phospholipid bilayer down a concentrated

8

What is facilitated diffusion?

Transport of molecules across plasma membranes down a concentration gradient with the aid of movement transport proteins

9

What are two types of membrane transport proteins?

Channels and Transporters

10

What are channels?

Membrane pores formed by proteins

11

What are transporters?

Bind to molecules on one side of the membrane in response to differences in solute concentrations

12

What is osmosis?

Diffusion of water across a selectively permeable membrane in response to differences in solute concentrations

13

Which way does osmosis ALWAYS occur?

From high to low concentrations

14

What are aquaporins?

Protein channels that allow facilitated diffusion of water

15

What is active transport?

Membrane transporter proteins use energy to move substances against their concentration gradients

16

What is a H+-ATPase proton pump?

Use of ATP to pump protons against a gradient

17

What is a symporter?

A protein that transports two substances in the same direction across a membrane

18

When is energy released in the H+-ATPase proton pump?

when protons pass down their gradient used to power active transport

19

What is a symporter used in?

The uptake of sugars, amino. acids, and nucleotide bases

20

Where are active transport cells abundant?

In root cell membranes

21

What does the water content of plants depend on?

Osmosis

22

What 2 things does osmosis depend on?

1. Solute. concentration

2. Turgor pressure

23

What is turgor pressure?

Hydrostatic pressure that increases as water enters plant cells

24

Why does turgor pressure increase?

Because cell walls restrict how much cells can swell

25

What are the two concepts to understand water potential?

1. To understand the movement of. water in and out of cells

2. To understand the movement of water between entire plants and their environment

26

What is the equation for. calculating cellular water potential?

Yw=Ys+Yp

27

What is the solute potential (Ys)

Presence of solutes:

- Pure water = 0

- What with solutes has a negative solute potential

28

What is the pressure potential (Yp)?

Hydrostatic Pressure:

- Turgid cells = positive Yw

- Flaccid and plasmolyze cells have a pressure potential of zero

29

What are the three forms of tissue-level transport?

1. Transmembrane transport

2. Symplastic transport

3. Apoplastic transport

30

What is transmembrane transport?

Export of material via membrane proteins, followed by import of the same substance by an adjacent cell

31

What is an example of transmembrane transport?

Auxin transport aided by carrier proteins

32

What is symplastic transport?

Movement from cytosol. of one cell to cytosol of another through plasmodesmat

33

What does symplastic transport allow transport of?

proteins, nucleic acids, and smaller molecules

34

What is apoplastic transport?

Movement along cell walls and intercellular spaces

35

What is an example of apoplastic movement?

Water and dissolved materials

36

In symplastic and apoplastic transport, where do nutrients enter through?

Outer tissues of roots

37

What substances does apoplastic transport move?

Soil water and dissolved minerals through root epidermal and cortex tissues

38

Where does apoplastic transport stop?

At root epidermis (barrier to central core of vascular tissue

39

What prevents apoplastic transport into root vascular tissues?

Casparian strips

40

What kind of flow is used for long-distance transport?

Bulk or mass flow

41

What is bulk or mass flow?

Mass movement of liquid caused by pressure, gravity, or both

42

What happens when water is abundant?

What pressure is higher in root xylem and shoot xylem

43

Where does pressure build up as organic solutes are produced by photosynthesis?

In phloem sap of leaves

44

Can the transport functions of xylem and phloem be reversed at times?

Yes

45

What are tracheary elements?

Tracheids and vessel elements

46

What are tracheary elements specialized in?

Water-conducting cells and are dead and empty of cytosol when mature

47

What element are treachery elements abundant in?

Lignin

48

Which treachery element (vessel element or tracheids) have a larger diameter and greater capacity for bulk flow?

Vessel elements

49

What is transpiration?

Evaporation of water from plant surfaces

50

What allows for pulling water up by bulk flow?

Transpiration

51

What is the primary form of long distance water transport in plants?

Transpiration

52

Is there energy needed for bulk flow?

No

53

What (indirect) form of energy powers transpiration?

Light Energy from the Sun

54

What is a characteristic of water is important for transpiration?

Cohesiveness

55

What is the cohesion-tension theory?

Cohesion and tension exerted on water by evaporation at plant's surface pulls a continuous stream of water from the soil

56

What does surface tension increase?

The intercellular spaces of cells, pulling on the water stream in xylem

57

What do plants produce to prevent water loss?

A waxy cuticle

58

What plant structure facilitates gas exchange?

Stomata

59

When stomata are open...?

O2 and water vapor are released and CO2 is taken up

60

What are guard. cells?

Cells that close to conserve water

61

What kind of light stimulates guard cell ion uptake, water flows in, cell expands and stomata opens?

Blue light

62

In the stomata, what happens at night?

Ions are pumped out, and the cell deflates

63

What substance can also close the stomata during the day?

Abscisic acid

64

For what plants is leaf abscission a valuable adaptation?

For desert plants and angiosperm trees of seasonally cold habitats

65

What is the purpose of leaf abscission?

Allows the plants avoid very low leaf water potentials and the consequent danger of xylem embolism

66

What kind of leaves are efficient for light capture but vulnerable to cold stress?

Broad and thin leaves

67

What kind of leaves reduces leaf surface evaporation?

Needle or scale-shaped leaves

68

What does ethylene stimulate from?

Abscission zone

69

What happens after. water supply is cut off to leaf and chlorophyll breaks down?

Revealing carotenoid and xanthophyll pigments (fall colors)

70

What do enzymes do?

breaks down cell-wall components of separation layer, causing petiole to break off

71

What is primary phloem?

Occurs in the. vascular. bundles of herbaceous plants

72

What is secondary phloem?

Occurs as the inner bark. of woody plants

73

What kind of phloem tissues remain live and retain at. lease some cytoplasmic components?

Mature

74

What are sieve-tube elements?

Arranged at the end to end, together with companion cells from a system to transport. soluble organic substances

75

Where does phloem sap pass through?

Sieve plate pores

76

What does a companion cell supply?

mRNA and proteins to sieve tube elements via plasmodesmata because lost its nucleus

77

How do the sieve-tube elements reduce obstruction to bulk flow?

By losing its nucleus and reduction of most of the cytoplasm

78

Which structure plays a role in conveying sugars to sieve-tube elements for long-distance transport?

Companion cells

79

What is used for most long distance transport?

Sucrose

80

What are the 2 types of phloem loading?

Symplastic

Partly apoplastic

81

What is symplastic?

Transportation of sucrose form sugar-producing cells of the leaf mesophyll to companion cells and then to sieve-tube elements via plasmodesmata

82

Does symplastic require energy?

No ATP, because sugar does not cross plasma membranes

83

Where does symplastic mostly occur, what plants?

Most woody plants

84

What is partly apoplastic and partly. transmembrane transport?

Loading of. sugar into sieve-tube elements or companion cells from intercellular spaces

85

Is ATP used for partly apoplastic and partly. transmembrane transport?

Yes, because sugar is moved across the plasma membrane

86

What kind of plants does partly apoplastic and partly. transmembrane transport occur in?

Herbaceous plants

87

What is the sugar source?

Leaf mesophyll

88

What is the sugar. sink?

Roots, developing leaves, seeds, fruits

89

What is phloem transport driven by?

Differences in turgor pressure between cells of a sugar source and sugar sink

90

Which way can. directions go?

Horizontal or vertical