Text C Biology 9.3 Water Transport In Plants

Question 1

What is the primary method of water transport from one individual plant cell to the next?

Answer 1

Osmosis

Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Question 2

How far can some trees transport water from root tips to the highest leaves?

Answer 2

100 m or more

This illustrates the efficiency of water transport systems in tall plants.

Question 3

What are the two main types of vessels in the plant vascular system?

Answer 3

Xylem and phloem

Xylem transports water and minerals, while phloem transports sugars.

Question 4

What is the role of xylem tissue in plants?

Answer 4

Transport water and dissolved minerals from the soil to the leaves

Xylem is essential for photosynthesis and plant hydration. Xylem is dead and forms tubes.

Question 5

What is the state of most xylem cells in a mature plant?

Answer 5

Dead

They form hollow tubes consisting of only the cell walls.

Question 6

What are xylem vessels?

Answer 6

Long continuous tubes formed by xylem cells linked end to end

They extend from near the tips of the roots into the rest of the plant.

Question 7

What function does water transported by xylem vessels serve in non-woody plants?

Answer 7

Prevents wilting

Water is crucial for maintaining turgor pressure in plant cells.

Question 8

What do phloem cells transport throughout the plant?

Answer 8

Sugars produced during photosynthesis

Phloem is vital for distributing energy resources within the plant.

Question 9

What distinguishes phloem cells from xylem cells?

Answer 9

Phloem cells are living cells

Their porous cell walls allow for material exchange with neighboring cells.

Question 10

How does sugary sap flow in phloem vessels?

Answer 10

By passing through porous cell walls

This allows for the flow of nutrients throughout the plant.

Question 11

What are vascular bundles in plants?

Answer 11

Strands of xylem and phloem grouped together

They are found in roots and stems, aiding in transport.

Question 12

True or False: Xylem vessels are made of living cells.

Answer 12

False

Xylem vessels consist of dead cells that form hollow tubes.

Question 13

Fill in the blank: The plant vascular system is made up of a series of interconnected _______.

Answer 13

Tubes

These tubes facilitate the transport of water, minerals, and sugars.

Question 14

What is the function of xylem?

Answer 14

Transports water and dissolved minerals from the roots to the leaves

Xylem is essential for water transport in plants.

Question 15

What does phloem carry?

Answer 15

Sugar-rich sap from the leaves throughout the plant

Phloem is responsible for the distribution of nutrients.

Question 16

What are the two types of structures found in xylem vessels?

Answer 16

• Tracheids
• Vessel elements

Both structures facilitate water transport.

Question 17

What happens to the contents of tracheids and vessel elements as they mature?

Answer 17

The contents die, leaving only the cell walls

This allows for efficient water movement.

Question 18

How do fluids move through the xylem?

Answer 18

Fluids pass from one tracheid or vessel element to the next

This movement is crucial for water transport.

Question 19

What connects tracheids in xylem?

Answer 19

Small pits in the end walls

These pits facilitate the flow of water.

Question 20

What connects vessel elements in xylem?

Answer 20

Perforations in the end walls

This connection is essential for water transport.

Question 21

What are the main components of phloem cells?

Answer 21

• Sieve tubes
• Companion cells

These components work together to transport nutrients.

Question 22

What structure separates the sieve tubes in phloem?

Answer 22

Sieve plates

Sieve plates are crucial for nutrient flow.

Question 23

How does water enter the root epidermis?

Answer 23

By osmosis

Osmosis is the primary method for water uptake.

Question 24

What increases the surface area for absorbing water in roots?

Answer 24

Root hairs

Root hairs are outgrowths that enhance water absorption.

Question 25

What is the role of the epidermal tissue in roots?

Answer 25

Covers the root and is permeable to water ## Footnote The epidermis plays a key role in water uptake.

Question 26

What prevents substances from moving between cells in the innermost layer of the root?

Answer 26

A waterproof seal around each cell ## Footnote This seal helps control water movement.

Question 27

Fill in the blank: Xylem transports water and dissolved minerals from the roots to the _______.

Answer 27

leaves ## Footnote Xylem is crucial for maintaining plant hydration.

Question 28

True or False: Phloem is responsible for transporting water from the roots to the leaves.

Answer 28

False ## Footnote Phloem transports nutrients, not water.

Question 29

What is a sieve plate?

Answer 29

A structure that separates sieve-tube elements in phloem

Question 30

What are tracheids?

Answer 30

Long hollow cells within xylem vessels that transport water

Question 31

What are vessel elements?

Answer 31

Types of xylem cells that also transport water and dissolved minerals

Question 32

What is xylem responsible for?

Answer 32

Transporting water and dissolved minerals from the roots to the leaves

Question 33

What does phloem carry?

Answer 33

Sugar-rich sap from the leaves throughout the plant

Question 34

What are the two main types of cells in phloem?

Answer 34

* Sieve tubes * Companion cells

Question 35

What connects tracheids in xylem?

Answer 35

Small pits in the end walls

Question 36

What connects vessel elements in xylem?

Answer 36

Perforations in the end walls

Question 37

What is the primary function of root hairs?

Answer 37

Increase surface area for absorbing water and dissolved minerals

Question 38

How does water enter the root epidermis?

Answer 38

By osmosis

Question 39

What is the core of the root composed of?

Answer 39

Xylem and phloem encircled by several layers of cells

Question 40

What covers the root?

Answer 40

Epidermal tissue

Question 41

Fill in the blank: Water and minerals enter a plant from the _______.

Answer 41

roots

Question 42

True or False: Both tracheids and vessel elements start as living cells.

Answer 42

True

Question 43

How do fluids move through the xylem?

Answer 43

From one tracheid or vessel element to the next

Question 44

What is the role of the waterproof seal around the cells in the root?

Answer 44

Prevents substances from moving between the cells

Question 45

What happens to the contents of tracheids and vessel elements as they mature?

Answer 45

They die, leaving only the cell walls

Question 46

What structure in phloem makes up the long tubes?

Answer 46

Sieve tubes and companion cells arranged end-to-end

Question 47

What type of diffusion do root cells use to move minerals across their membranes?

Answer 47

Facilitated diffusion or active transport ## Footnote Active transport is used when moving against a concentration gradient.

Question 48

What is the solution of water and minerals that accumulates in the root xylem called?

Answer 48

Xylem sap

Question 49

What do xylem vessels carry from the roots to the leaves?

Answer 49

Xylem sap

Question 50

What happens to xylem vessels as they enter the leaves?

Answer 50

They branch into many veins visible on the leaf surface.

Question 51

What do the cells at the end of each xylem vessel absorb?

Answer 51

Water and minerals

Question 52

True or False: Water readily diffuses across cell membranes.

Answer 52

True

Question 53

Fill in the blank: The process of moving minerals against a concentration gradient requires _______.

Answer 53

Active transport

Question 54

What is the primary function of xylem vessels?

Answer 54

To transport xylem sap upward from the roots

Question 55

What property of fluid in the xylem allows it to flow against gravity?

Answer 55

Investigated in the next Find Out Activity

Question 56

What is the force that allows water to rise in a continuous column within xylem vessels?

Answer 56

Cohesion ## Footnote Cohesion is the tendency of water molecules to stick to each other due to weak electrical forces.

Question 57

What happens if the column of water within a xylem vessel breaks?

Answer 57

Water above the break can be pulled upward, but the sap cannot rise past the break ## Footnote A break in the water column, such as a bubble, blocks the rising xylem sap.

Question 58

What is adhesion in the context of water properties?

Answer 58

The tendency of water molecules to stick to certain surfaces ## Footnote Adhesion helps water resist gravity by clinging to xylem walls.

Question 59

What role does root pressure play in plant water transport?

Answer 59

Pushes fluid upward in the xylem ## Footnote Root pressure is created by turgor pressure from water entering the root xylem due to osmosis.

Question 60

How does turgor pressure contribute to root pressure?

Answer 60

It builds up as water flows into the xylem due to increased mineral concentration ## Footnote Active transport of minerals into the xylem raises the osmotic pressure, drawing water in.

Question 61

What is the effect of adhesion on xylem sap movement?

Answer 61

It helps the sap climb upward in the xylem vessels ## Footnote The adhesion of xylem sap to the walls prevents it from falling back down.

Question 62

Fill in the blank: The upward movement of water in plants can occur through _______ and pulling mechanisms.

Answer 62

pushing ## Footnote Root pressure is an example of the pushing mechanism.

Question 63

True or False: A break in the xylem water column has no impact on water transport.

Answer 63

False ## Footnote A break in the column blocks the upward movement of xylem sap.

Question 64

What can cause bubbles to form in xylem sap?

Answer 64

Freezing in winter ## Footnote Bubbles disrupt the continuous column of water necessary for effective transport.

Question 65

What is the primary mechanism by which water moves into root xylem?

Answer 65

Osmosis ## Footnote Water diffuses into the xylem due to the increased concentration of minerals.

Question 66

What is the maximum height that root pressure can move water upward?

Answer 66

A few meters at most

Question 67

Why is root pressure not sufficient for tall trees to raise water to significant heights?

Answer 67

Root pressure would need to be more than 10 times greater than atmospheric pressure, which has never been demonstrated

Question 68

What generates the pulling force for water transport in plants?

Answer 68

Transpiration from the leaves

Question 69

What is the beneficial effect of transpiration on plants?

Answer 69

It helps in water transport despite the risk of drying out

Question 70

How does the Sun contribute to transpiration?

Answer 70

It causes water to evaporate from the leaves

Question 71

What happens to the air within the leaf as water vapor exits?

Answer 71

It becomes slightly drier

Question 72

What causes more water to evaporate from the surface of leaf cells?

Answer 72

The diffusion of water out of the leaf cells into the fluid between the cells

Question 73

What role do cohesive forces between water molecules play in transpiration?

Answer 73

They cause more water to be pulled up the xylem vessels

Question 74

What is the pathway of water movement from the soil to the leaves?

Answer 74

Water travels upward through xylem vessels to the leaf cells

Question 75

What creates the unbroken chain of water in the xylem vessels?

Answer 75

Transpirational pull exerted throughout the xylem

Question 76

Fill in the blank: The energy for xylem transport comes from the _______.

Answer 76

[Sun]

Question 77

What is the maximum speed at which xylem sap can flow upward?

Answer 77

Faster than 15 m/h

Question 78

How long would it take for water to travel from the roots to the leaves in a tree 80 m tall with roots 20 m deep at a speed of 15 m/h?

Answer 78

Approximately 4 hours

Question 79

What keeps the water column in place within the xylem?

Answer 79

Adhesion

Question 80

What holds the water column together in the xylem?

Answer 80

Cohesion between water molecules

Question 81

What is the role of stomata in transpiration?

Answer 81

They allow water vapor to exit the leaf

Question 82

True or False: Many tall trees show measurable root pressure.

Answer 82

False

Question 83

What do scientists use to study phloem?

Answer 83

Insects called aphids ## Footnote Aphids drink the water and nutrients in phloem.

Question 84

What is the needle-like mouthpart of an aphid called?

Answer 84

Stylet ## Footnote The stylet pierces a single phloem cell.

Question 85

How do researchers collect phloem for analysis?

Answer 85

By anaesthetizing an aphid and cutting off its stylet ## Footnote The stylet is left in place to tap the phloem.

Question 86

What must happen to sugars before they can be used by cells in other parts of the plant?

Answer 86

They must be transported from the leaves to the stem, roots, and growing shoots and fruits.

Question 87

What transports sugars and other substances throughout the plant?

Answer 87

Phloem vessels

Question 88

How are sugars and nutrients pumped into the leaf phloem?

Answer 88

By active transport

Question 89

What causes water to move into the phloem by osmosis?

Answer 89

The increase in sugar concentration within the phloem cells.

Question 90

What is the mixture of sugar, nutrients, and water in phloem called?

Answer 90

Phloem sap

Question 91

What happens to the pressure in the phloem when sucrose enters the leaf?

Answer 91

It increases ## Footnote Water moves into the phloem by osmosis, causing this increase.

Question 92

What causes the concentration of sucrose solution to decrease in the phloem?

Answer 92

Removal of sucrose by the tissues of the plant stem and root.

Question 93

What happens to water when the concentration of sucrose in the phloem decreases?

Answer 93

Water moves out of the phloem by osmosis.

Question 94

What is the flow direction of phloem sap under normal conditions?

Answer 94

From leaf to root

Question 95

What does the pressure gradient between the leaf and root cause?

Answer 95

A flow of solution through the phloem

Question 96

What happens to some of the phloem sap as it travels down to the roots?

Answer 96

It leaves the phloem and nourishes the surrounding tissue.

Question 97

In which tissues does the pressure within the phloem remain low?

Answer 97

Growing shoots, roots, fruits, and other organs that store energy.

Question 98

True or False: The pressure in the roots is usually higher than in the leaves.

Answer 98

False

Question 99

What do scientists use to study phloem?

Answer 99

Insects called aphids ## Footnote Aphids drink the water and nutrients in phloem.

Question 100

What is the needle-like mouthpart of an aphid called?

Answer 100

Stylet ## Footnote The stylet pierces a single phloem cell.

Question 101

How do researchers collect phloem for analysis?

Answer 101

By anaesthetizing an aphid and cutting off its stylet ## Footnote The stylet is left in place to tap the phloem.

Question 102

What must happen to sugars before they can be used by cells in other parts of the plant?

Answer 102

They must be transported from the leaves to the stem, roots, and growing shoots and fruits.

Question 103

What transports sugars and other substances throughout the plant?

Answer 103

Phloem vessels

Question 104

How are sugars and nutrients pumped into the leaf phloem?

Answer 104

By active transport

Question 105

What causes water to move into the phloem by osmosis?

Answer 105

The increase in sugar concentration within the phloem cells.

Question 106

What is the mixture of sugar, nutrients, and water in phloem called?

Answer 106

Phloem sap

Question 107

What happens to the pressure in the phloem when sucrose enters the leaf?

Answer 107

It increases ## Footnote Water moves into the phloem by osmosis, causing this increase.

Question 108

What causes the concentration of sucrose solution to decrease in the phloem?

Answer 108

Removal of sucrose by the tissues of the plant stem and root.

Question 109

What happens to water when the concentration of sucrose in the phloem decreases?

Answer 109

Water moves out of the phloem by osmosis.

Question 110

What is the flow direction of phloem sap under normal conditions?

Answer 110

From leaf to root

Question 111

What does the pressure gradient between the leaf and root cause?

Answer 111

A flow of solution through the phloem

Question 112

What happens to some of the phloem sap as it travels down to the roots?

Answer 112

It leaves the phloem and nourishes the surrounding tissue.

Question 113

In which tissues does the pressure within the phloem remain low?

Answer 113

Growing shoots, roots, fruits, and other organs that store energy.

Question 114

True or False: The pressure in the roots is usually higher than in the leaves.

Answer 114

False

Question 115

Who is Dr. Malcolm King?

Answer 115

A professor of the pulmonary division at the University of Alberta specializing in traditional Aboriginal remedies

Question 116

What is the primary focus of Dr. King's research?

Answer 116

Exploring herbal medicine for treating respiratory illnesses

Question 117

Name two diseases Dr. King researches.

Answer 117

* Asthma * Bronchitis * Cystic fibrosis

Question 118

What has Dr. King patented?

Answer 118

Two therapies for chronic respiratory disease

Question 119

What role do diffusion and active transport play in plants?

Answer 119

They are important for water transport

Question 120

What do xylem vessels transport?

Answer 120

Water and dissolved minerals from the soil to the leaves

Question 121

What are the components of xylem vessels?

Answer 121

* Tracheids * Vessel elements

Question 122

What do phloem vessels transport?

Answer 122

Sugars produced during photosynthesis throughout the plant

Question 123

What type of cells make up phloem tissue?

Answer 123

Living cells

Question 124

How does water first enter plant roots?

Answer 124

By osmosis

Question 125

How do root hairs contribute to water absorption?

Answer 125

They increase the surface area for osmosis

Question 126

How are minerals moved into the root?

Answer 126

By facilitated diffusion or active transport

Question 127

What properties of water allow fluid to flow through xylem against gravity?

Answer 127

* Cohesion * Adhesion

Question 128

What creates the pushing pressure in the root xylem?

Answer 128

Turgor pressure

Question 129

What facilitates the pulling force of water movement through plants?

Answer 129

Transpiration through the leaves

Question 130

Fill in the blank: Xylem vessels are made of long, hollow, _______ cells.

Answer 130

dead

Question 131

True or False: Phloem vessels are made of dead cells.

Answer 131

False

Question 132

Which root extract worked well to clear mucus in Dr. King's experiments?

Answer 132

Licorice root

Question 133

What is the reason Dr. King believes licorice root is effective for mucus clearance?

Answer 133

The complex sugars that give licorice its distinctive sweetness

Question 134

Describe the structure of the cells that make up phloem tissue.

Answer 134

Phloem cells are living cells

Question 135

Will a daisy plant transpire more in a humid environment or in a dry environment? Explain.

Answer 135

In a dry environment due to higher evaporation rates

Question 136

Explain why root pressure alone cannot transport water from the roots.

Answer 136

It is insufficient to overcome gravity without additional forces like transpiration