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Biology - Module 3 > Chapter 9 - Transport In Plants > Flashcards

Chapter 9 - Transport In Plants Flashcards

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1
Q

Why do large organisms need transport systems

A

o Increasing transport distances
o Surface area: volume ratio
o Increasing levels of activity

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2
Q

Why do small organisms not need transport systems

A

o due to their large surface area: volume ratio
o diffusion or transport distance in these organisms are also very small so essential nutrients or molecules are able to reach the necessary parts of the cell efficiently
o Smaller organisms tend to have lower levels of activity and so smaller metabolic demands

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3
Q

Why do plants need specialised transport system

A

-to remove products of photosynthesis + water + oxygen

  • large organisms = huge distances to transport
  • SA:V ratio = small
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4
Q

Define vascular system

A

A system of transport vessels in plants or animals

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5
Q

Define herbaceous

A

Having fleshy / soft stem

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6
Q

What is the impact of large transport systems

A

makes simple diffusion a non-viable method for transporting substances all the way from the exchange site to the rest of the organism

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7
Q

If the organism is small

A

Large SA:V ratio

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8
Q

Define dicotyledonous

A

Plants that produce two seed leaves

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9
Q

Adaptations of plants to increase SA : V

A

• Plants have a branching body shape

Leaves are flat and thin

Roots have root hairs

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10
Q

How does increasing levels of activity effect oxygen demand

A

• Larger organisms are not only more physically active but they also contain more cells than smaller organisms
• A larger number of cells results in a higher level of metabolic activity
o As a result, the demand for oxygen and nutrients is greater and more waste is produced

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11
Q

What is mass flow

A

bulk movement of materials.

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12
Q

Advantages / functions of mass transport

A

o Bring substances quickly from one exchange site to another
o Maintain the diffusion gradients at exchange sites and between cells and their fluid surroundings
o Ensure effective cell activity by keeping the immediate fluid environment of cells within a suitable metabolic range

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13
Q

What does the xylem transport

A

water + mineral ions

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14
Q

What does the phloem transport

A

sucrose + other nutrients = assimilates

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15
Q

Do plants have specialised transport system for oxygen + carbon dioxide

A

NO

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16
Q

Why don’t they have a specialised transport system for oxygen and carbon dioxide

A

They don’t need one

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17
Q

Why don’t they need a specialised transport system for oxygen and carbon dioxide

A

o They have adaptations that give them a high SA: V ratio for the absorption and diffusion of gases

o The leaves and stems possess chloroplasts which produce oxygen and use up carbon dioxide

o There is a low demand for oxygen due to plant tissues having a low metabolic rate

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18
Q

Why do plants need water - 5

A
  • maintain turgidity of cells
  • transport nutrients around the plants
  • create an aqueous environment for reactions to occur
  • to cool plants by evaporation
  • for photosynthesis
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19
Q

From the inside to the outside what tissues are present in a root dissection

A

Xylem

Phloem

Pericycle

Endodermis

Cortex

Epidermis = root hair cells

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20
Q

Functions of the xylem

A

carries dissolved minerals and water up the plant
o Structural support
o Food storage

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21
Q

What type of tissue is the xylem

A

Vascular

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22
Q

Where is the xylem found

A

in vascular bundles with phloem

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23
Q

Where is the vascular bundle found in the roots

A

the centre and t he centre core of this is xylem tissue.

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24
Q

Advantages of the vascular bundle in the centre of the roots

A

helps the roots withstand the pulling strains they are subjected to as the plant transports water upwards and grows

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25
Q

Where is the vascular bundle found in the stem

A

located around the outside and the xylem tissue is found on the inside (closest to the centre of the stem)

= CONCENTRIC RINGS

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26
Q

Why is the vascular found in concentric rings at the stem

A

Help support the plant

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27
Q

Where is the vascular bundle found in the leaves

A

the midrib and veins and therefore spread from the centre of the leaf in a parallel line.

The xylem tissue is found on the upper side of the bundles (closest to the upper epidermis)

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28
Q

Function of the phloem

A

o Transport organic compounds, particularly sucrose, from the source (eg. leaf) to the sink (eg. roots).

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29
Q

Is the phloem two way

A

Yes

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30
Q

What is the phloem made of

A

Sieve tube elements

Companion cells

parenchyma

Sclerenchyma

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31
Q

Key difference in place of vascular bundles

A

In roots and stem, the xylem tissue is found on the inside – however, in leaves, xylem is found above phloem tissue.

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32
Q

What is the xylem made of

A

Tracheids

Vessel elements

Xylem parenchyma

Sclerenchyma

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33
Q

What are tracheids

A

Long narrowed tapered cells with pits

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34
Q

What are vessel elements

A

Larger cells with thickened cell walls and no end plates ( when matured )

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35
Q

What is common about tracheids and vessel elements

A

both types of water-conducting cell

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36
Q

Function of lignified cell walls in xylem

A
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37
Q

Features of the xylem

A

Lignified cell walls

No end plates

No protoplasm

Pits

Small diameter of vessels

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38
Q

Function of no end plates in mature xylem cells

A
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39
Q

Function of no protoplasm in mature xylem cells

A
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40
Q

Function of pits

A
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41
Q

Function of small diameter of vessels

A
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42
Q

Components of the phloem

A

• Sieve tube elements
• Companion cells
• Parenchyma
• Sclerenchyma
• Living cells

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43
Q

Features of sieve tube elements

A

Sieve plates + sieve pores

Cellulose cell wall

No nucleus / vacuole / ribosomes

Thin cytoplasm

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44
Q

Function if seive plates + seive pores

A
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45
Q

Function of cellulose cell wall

A
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46
Q

Function of no nucleus / vacuole / ribosomes

A

Maximises space for translocation of the assimilates

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47
Q

What is sometimes present in seive tube elements

A

ER + mitochondria

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48
Q

Function of thin cytoplasm

A
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49
Q

Function of companion cells

A
  • control metabolism of seive tube elements
  • loading + unloading of sugars
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50
Q

Key features of companion cells

A
  • nucleus + other organelles present
  • transport proteins in plasma membrane
  • large numbers of mitochondria
  • plasmodesmata
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51
Q

Function of nucleus + other organelles present in companion cells

A
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52
Q

Function of transport proteins in plasma membrane of companion cells

A
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53
Q

Function of a lot of mitochondria in companion cells

A
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54
Q

Function of plasmodesmata in companion cells

A
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55
Q

Xylem vs phloem : living cells (mature)

A

Xylem - no living cells

Phloem - yes = companion cells

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56
Q

Xylem vs phloem : transported substances

A

Xylem - water + mineral ions

Phloem - organic compounds / assimilates

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57
Q

Xylem vs phloem : process of transportation

A

Xylem - transpiration

Phloem - translocation

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58
Q

Xylem vs phloem : direction of flow

A

Xylem - one way / roots to leaves

Phloem - two way = source to sink

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59
Q

Xylem vs phloem : presence of end walls

A

Xylem - no

Phloem = yes = sieve plates with sieve pores

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60
Q

Xylem vs phloem : cell wall material

A

Xylem = lignin + cellulose

Phloem = cellulose

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61
Q

Features of Dicotyledonous (dicots) plants

A

o Seeds that contain two cotyledons (seed leaves)
o Network of veins
o Leaves that typically have broad blades (leaf surface) and petioles (stalks)
o Tap root with lateral branches

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62
Q

Why do plants need transport systems

A
  • meet metabolic demands
  • move substances around the plant
  • compensate for small SA:V ratio
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63
Q

What does the palisade mesophyll contain

A

Parenchyma cells

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64
Q

From top to bottom of a leaf - name structures

A

Upper epidermis

Palisade mesophyll

Xylem

Phloem

Spongy mesophyll

Lower epidermis

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65
Q

Define transpiration

A

• he tloss of water vapour from a plant to its environment by evaporation and diffusion

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66
Q

What’s transpiration a consequence of

A

• gaseous exchange at the stomata

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67
Q

Advantages of transpiration

A

• provides a means of cooling the plant via evaporative cooling

• The transpiration stream is helpful in the uptake of mineral ions

• The turgor pressure of the cells (due to the presence of water as it moves up the plant) provides support to leaves (enabling an increased surface area of the leaf blade) and the stem of non-woody plants

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68
Q

Define transpiration stream

A

• the movement of water from the roots to the leaves

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69
Q

What causes the movement of water through a plants xylem

A

evaporation of water vapour from the leaves and the cohesive and adhesive properties exhibited by water molecules

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70
Q

Describe the transpiration stream = beginning of the stream at the leaves

A
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71
Q

Factors effecting rate of transpiration

A

• Air movement / light intensity / temperature / humidity

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72
Q

How does air movement effect rate of transpiration

A

• When the air is relatively still water molecules can accumulate near the leaf surface. This creates a local area of high humidity which lowers the concentration gradient and the rate of transpiration

• Air currents can sweep water molecules away from the leaf surface, maintaining the concentration gradient and increasing the rate of transpiration

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73
Q

How does temperature effect rate of transpiration

A

= increase temp = increase KE = rate of transportation will increase

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74
Q

What happens if the temp gets too high in relation to transpiration

A

• the stomata close to prevent excess water loss.

dramatically reduces the rate of transpiration

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75
Q

How does light intensity effect rate of transpiration

A

• Stomata close in the dark, their closure greatly reduces the rate of transpiration
• When the light is sufficient for the stomata to open, the rate of transpiration increases

• Once the stomata are open any increase in light intensity has no effect on the rate of transpiration
• Stomata will remain open at relatively low light intensities

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76
Q

How does humidity effect rate of transpiration

A

• If the humidity is high that means there is a large concentration of water molecules in the airsurrounding the leaf surface

• This reduces the concentration gradient between inside the leaf and the outside air which causes the rate of transpiration to decrease

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77
Q

What happens at a certain level of humidity

A

• an equilibrium is reached; there is no concentration gradient and so there is no net loss of water vapour from the leaves

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78
Q

Draw graph for rate of transportation against temp

A
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79
Q

Draw graph for rate of transportation against humidity

A
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80
Q

Draw graph for rate of transportation against air movement

A
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81
Q

Draw graph for rate of transportation against light intensity

A
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82
Q

What occurs via osmosis in transpiration

A

Uptake of water to the roots

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83
Q

What occurs by active transport in transportation

A

Uptake of mineral ions in the roots

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84
Q

How does the plant ensure that the water potential of the root is more negative than the soil

A

Ions from the soil are ACTIVELY pumped into the root

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85
Q

What does active pumping mean

A

Energy required for movement

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86
Q

What pathway is taken by the water to go from the soil to the xylem

A

Root hair cell

Cortex

Endodermis

Pericycle

Xylem

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87
Q

What are the two different routes the water can take to the xylem

A

Apoplast + symplast

88
Q

What’s the function of the pericycle

A

It is meristematic + produces the lateral roots

89
Q

What is the function of the endodermis

A

Contains a ring of Suberin which is impermeable to water

90
Q

What is the function of the cortex

A

Stores a large amount of starch

91
Q

What path does most water travel through

A

Apoplastic

92
Q

What is the apoplast pathway

A

Water travels through cellulose cell walls

93
Q

How does the water move in the apolast pathway

A
  • moved by diffusion = as it is not crossing partially permeable membrane
94
Q

What’s the problem with the apoplast pathway

A

• When the water reaches the endodermis the presence of a thick, waterproof, waxy band of suberin within the cell wall blocks the apoplastic pathway

95
Q

What is the band of Suberin called

A

the Casparian strip

96
Q

Key property of the casparian strop

A

Impermeable to water

97
Q

What happens to the water when it reaches the casparian strip

A
  • they must take the symplast pathway
98
Q

Advantages of apoplast pathway

A
  • much quicker
  • offers path of least resistance
99
Q

What is the function of the Casparian strip

A

• help the plant control which mineral ions reach the xylem and generate root pressure

100
Q

As the plant ages, what happens to the casparian strip

A

Thickens

101
Q

How does water enter the xylem from the endodermis

A
  • endoderm cells actively pump salts into the xylem
  • makes water potential of the xylem more negative than the endodermal cells
  • this means water enters the xylem via osmosis
  • ensures water potential gradient is maintained
102
Q

Where is the casparian strip located

A

In the endodermal cells

103
Q

How do endodermal cells move ions into the xylem

A

Active transport

104
Q

Once water has entered the xylem how does it move

A

As a continuous stream

105
Q

What force is created by the bonds between water molecules

A

Cohesion

106
Q

What force is created by the interaction between water molecules + vessel

A

Adhesion

107
Q

How is the continuous streak created

A

Cohesion + adhesion

108
Q

What’s another way water can enter to the xylem

A

Symplast

109
Q

What is symplast

A

Water travels through the cytoplasm + from cell to cell via the plasmodesmata

110
Q

What three processes are involved in the movement of water up the stem + through the leaves

A
  • root pressure
  • capillarity
  • cohesion - tension theory
111
Q

What causes root pressure

A
  • endodermal cells actively pump ions into the xylem vessel
  • water potential gradient formed + water enters the xylem
  • pressure in the xylem increases = forcing water upwards
112
Q

What is the evidence for root pressure

A
  • if cyanide is added to the root = sap is no longer exuded
  • root pressure replies on the active pumping of ions which requires ATP
  • if there is no ATP = no pumping = no water potential gradient
  • therefore no water entering xylem
  • no root pressure
113
Q

What causes capillarity

A
  • adhesive forces between xylem vessels + water molecules
  • pulls water molecule up
  • due to cohesive forces = other molecules are pulled up with it
114
Q

Why is the xylem a bundle of very narrow vessels rather than one wide vessels

A
  • greater heights of liquid are achieved in thinner tubes due to capillarity
  • with smaller tubes = greater contact with vessel wall compared with the volume of water at the Center
  • so greater cohesive + adhesive forces
115
Q

What is transpiration = Howard definition

A

Loss of WATER VAPOUR from leaves + stem as a result of evaporation from cell surfaces inside the leaf and diffusion down a conc gradient out through stomata

116
Q

Why is transpiration pull referred to as the cohesion - tension theory

A
  • cohesive force between water molecules pulls other molecules up = continuous stream
  • puts pressure on the column of water
  • inward pressure is called tension
117
Q

What effect does tension have on the column of water

A

Produces narrower column of water

118
Q

Water happens if a xylem vessel is broken

A

The continuous stream of water is broken so no water can be taken up

119
Q

If a xylem vessel becomes blocked can water still reach the leaves

A

Yes

120
Q

Why can water still reach the leaves if a xylem vessel becomes blocked

A

The pits in the xylem allows for the movement of water

121
Q

How does the water move through leaves

A
122
Q

What is the role of the stomata in transpiration

A

• Transpiration is mainly controlled by the pairs of guard cells that surround stomata (plural, stoma is singular)

123
Q

Label the parts of the leaf

A
124
Q

Method to investigate rate of transpiration

A

• Cut a shoot underwater
• Place the shoot in the tube
• Set up the apparatus
• Make sure it is airtight, using vaseline to seal any gaps
• Dry the leaves of the shoot
• Remove the capillary tube from the beaker of water to allow a single air bubble to form and place the tube back into the water
• Set up the environmental factor you are investigating
• Allow the plant to adapt to the new environment for 5 minutes
• Record the starting location of the air bubble
• Leave for a set period of time
• Record the end location of the air bubble
• Change the light intensity or wind speed or level of humidity or temperature
• Reset the bubble by opening the tap below the reservoir
• Repeat the experiment

125
Q

How to analyse result from transpiration experiment

A

The further the bubble travels in the same time period, the faster transpiration is occurring and vice versa

126
Q

Apparatus for transpiration experiment

A
127
Q

Why do we cut the shoot underwater

A

o prevent air from entering the xylem

128
Q

Why do we make sure it is airtight

A

o If air enters the apparatus the readings will be affected

129
Q

Why do we dry the leaves

A

o Any moisture present on the leaves will affect the rate of transpiration

130
Q

How to investigate airflow

A

Hairdryer / fan

131
Q

How to investigate humidity

A

Spray water in a plastic bag + wrap around the plant

132
Q

How to investigate light intensity

A

Change the distance of a light source from the plant

133
Q

How to investigate temperature

A

Temp of room

134
Q

What makes up the vascular bundle

A

Xylem

Cambium

Phloem

Sclerenchyma

135
Q

What is the function of the cambium

A

It is meristematic + differentiates to form xylem + phloem as the plant grows

136
Q

What is the advantage of xylem vessels not being fully lignified

A

Allows stem to flex + move = Pits

137
Q

Example for what is glucose used for

A

Aerobic respiration

138
Q

Example of what plants use lipids for

A

Cell membrane

139
Q

Example of what plant uses proteins for

A

Enzymes

140
Q

Example of what plants use nucleic acids for

A

DNA replication

141
Q

Define assimilates

A

Products of photosynthesis/ respiration

142
Q

What is translocation

A

• transport of assimilates from source to sink and requires the input of metabolic energy (ATP)

143
Q

What is the liquid called that’s being transported in translocation

A

Phloem sap

144
Q

Direction of translocation

A

Source to sink

145
Q

Examples of sources

A

• Green leaves and green stem (photosynthesis produces glucose which is transported as sucrose, as sucrose has less of an osmotic effect than glucose)

• Storage organs eg. tubers and tap roots (unloading their stored substances at the beginning of a growth period)

• Food stores in seeds (which are germinating)

146
Q

Examples of sinks

A

• Meristems (apical or lateral) that are actively dividing

• Roots that are growing and / or actively absorbing mineral ions

• Any part of the plant where the assimilates are being stored (eg. developing seeds, fruits or storage organs)

147
Q

Can loading + unloading be stopped

A

Yes

148
Q

How can loading + unloading be stopped

A

• can be slowed down or even stopped at high temperatures or by respiratory inhibitors

149
Q

Evidence for translocation

A

• Collecting and studying the sap from plants with ‘clotting’ sap (eg. castor oil plants)

• Using aphids to collect the sap – after the aphid inserts its stylet (tubular mouthpart) scientists remove the aphids head and collect the sap that continues to flow

• Using radioactively labelled metabolites (eg. Carbon-14 labelled sugars) which can be traced during translocation

• Advances in microscopes enabling the adaptations of companion cells to be seen

150
Q

How is carbohydrates transported

A

In the form of sucrose

151
Q

Why is carbohydrates transported in the form of sucrose

A

o allows for efficient energy transfer and increased energy storage (sucrose is a disaccharide and therefore contains more energy)

o It is less reactive than glucose as it is a non-reducing sugar and therefore no intermediate reactions occur as it is being transported

152
Q

How are assimilates loaded

A

• modified companion cells pump hydrogen ions out of the cytoplasm via a proton pump and into their cell walls / source = active

• The large concentration of hydrogen ions in the cell wall of the companion cell / source results in the hydrogen ions moving down the concentration gradient back to the cytoplasm of the companion cell

• But cant diffuse back due to phospholipid bilayer = polar crap = Therefore moves through cotransporter protein.

• While transporting the hydrogen ions = also carries sucrose molecules into the companion cell against the concentration gradient for sucrose

• The sucrose molecules then move into the sieve tubes via the plasmodesmata from the companion cells

153
Q

How does sucrose move down the phloem

A

• now sucrose in sieve tube elements

• Decreases water potential

• As xylem vessels right next to phloem = water moves into phloem down water potential gradient = pits

• Now very high hydrostatic pressure in sieve tube

  • sink = very low hydrostatic pressure = down conc gradient
154
Q

Unloading at sink

A

• When sucrose goes into sink = converted into starch = to maintain concentration gradient

• Low concentration of sucrose in sink

• Therefore starch goes from sieve tube elements to companion cells to sink = through plasmodesmata

• All down concentration gradient = passive

• Therefore this increases water potential in sieve tube elements as sucrose in sink now

• Now low hydrostatic pressure = ultimately assimilates gone from high to low hydrostatic pressure

• Water goes from phloem back to xylem = follows water potential gradient

155
Q

What do plant cells use sucrose for

A
  • convert into starch for storage
  • respiration
156
Q

Advantage of the mass flow hypothesis

A

• moves the organic solutes faster than diffusion

157
Q

How is the pressure difference created in the mass flow of assimilates

A

• by actively loading sucrose into the sieve elements at the source(usually a photosynthesising leaf or storage organ) which lowers the water potential in the sap

• This results in water moving into the sieve elements as it travels down the water potential gradient by osmosis

158
Q

What actually causes mass flow

A

Hydrostatic pressure differences

159
Q

Summaries translocation = steps

A
160
Q

How do guard cells differ from the lower epidermal cells

A
  • they contain chloroplasts
  • have extra cellulose thickening on the inner side of cell
161
Q

Outline how guard cells open

A
  • cells surrounding guard cells actively pump K+ ions into the guard cells, making their water potential more negative
  • water enters by osmosis as water potential of guard cells more negative than surrounding p

-guard cells swell but because inner wall thicker than outer wall = as cell swells a pore opens

162
Q

What is crucial about the cell walls of guard cells

A

The inner wall is thicker than the outer wall

163
Q

Outline how guard cells close

A

K+ ions diffuse out of the guard cells + back into epidermal cells

No longer more negative water potential

Guard cells become flaccid

164
Q

Give 4 ways plants generally conserve water

A
  • waxy cuticle
  • stomata on underside of leaf
  • closable stomata
  • roots that grow down to the water in the soil
165
Q

What is a xerophyte

A

• plants that are adapted to dry and arid conditions

166
Q

Give two examples of xerophytes

A

Conifers + marram grass

167
Q

Examples of xerophyte adaptations

A
  • fleshy succulent leaves
  • hinge cells shrink when flaccid
  • spines / needles
  • sunken stomata

-less stomata

  • thick waxy cuticle
168
Q

Effect of fleshy succulent leaves

A

Water stores for times of low availability

169
Q

Effect of hinge cels shrinking when flaccid

A

Causes leaves to roll = exposing thick waterproof cuticle to air + creates a humid space in the middle of the rolled leaves

170
Q

Effects of spines / needles

A

Reduces transpiration rate due to reduces surface area

171
Q

Effect of sunken stomata

A

Water loss is minimised by trapping moist air close to the area of water loss = reducing diffusion gradient

172
Q

Effect of less stomata

A

Less water loss due to fewer pores

173
Q

Effect of thick waxy cuticle

A

Water loss reduced via the cuticle

174
Q

How do sunken stomata help to adapt a plant to hot + dry conditions

A
  • reduce air movement
  • create microclimate of still, humid air
  • reduces gradient = reduces transpiration rate
175
Q

What is a downside of reduced number of stomata

A

Reduces gas exchange capillaries

176
Q

How do hairy leaves adapt xerophytes

A
  • create microclimate of still, humid air
  • reduces water vapour potential gradient
177
Q

How do curled leaves adapt xerophytes

A
  • confine all stomata within a microenvironment of still, humid air
  • reduce diffusion gradient
178
Q

How are succulents adapted to their environment

A
  • contain specialist parenchyma tissue in stems + roots
  • stores water there - used in times of draught
179
Q

How can losing leaves adapt a xerophyte

A
  • leaves lost when water is not available
  • reduces water loss by transpiration
  • trunk + branches turn green + photosynthesis
180
Q

How do xerophytes have roots adapted for their environment

A
  • long tap roots grow deep into the ground below surface
  • mass widespread shallow roots with large surface area are able to absorb water before a rain shower evaporates
181
Q

Why is a hydrophyte

A

Plants that are adapted to living in freshwater

182
Q

State two examples of hydrophytes

A

Water lilies + water cress

183
Q

Problems faced by hydrophytes

A
  • water logging = air spaces of plants need to be full or air not water
  • Important that leaves float on the water to enable photosynthesis
  • receiving enough carbon dioxide during the day + neigh oxygen during the night = water contains less oxygen + carbon dioxide then air
184
Q

Adaptations of hydrophytes

A
  • floating leaves
  • air sacs
  • wide flat leaves
  • think waterproof waxy cuticle
  • stomata on upper surface of the leaves
  • reduced root system
  • reduced veins in the leaves
  • permentantly open stomata
185
Q

Why is excess water uptake not a major concern for hydrophytes

A

Cell wall prevents too much water being absorbed

186
Q

How does having thin / no waxy cuticle adapt hydrophytes

A

Allows water to be lost via transpiration

187
Q

How does having many stomata /permanently open adapt hydrophytes

A

Maximises gas exchange

188
Q

Why do hydrophytes have reduced structural support

A

Water supports leaves + flowers

189
Q

How does having wide flat leaves adapt hydrophytes

A

Spread across surface of water = maximise light absorption

190
Q

Why do hydrophytes have small roots

A

Water + nutrients can diffuse directly into stem + leaf tissue = less need for uptake via roots

191
Q

How do air sacs adapt hydrophytes

A

Enable leaves to float

192
Q

How does floating leaves adapt hydrophytes

A

Keeps them close to surface of water = maximise light

193
Q

How does stomata located on upper surface of leaves in hydrophytes adapt

A

Allows gas exchange with air not water

194
Q

Effect of reduced veins in the leaves of hydrophytes

A

Xylem is significantly reduces = less / no need to transport water

195
Q

What are aerenchyma

A

Specialised parenchyma tissue which has many large air spaces

196
Q

How do aerenchyma adapt hydrophytes

A
  • makes leaves + stems more Buoyant
  • form low resistance pathway for the movement of substances = e.g oxygen = to tissues below water
  • help plant cope with extreme low oxygen conditions
197
Q

Differnces between tracheids + vessel elements

A
198
Q
A
199
Q
A
200
Q
A

DNA

201
Q
A
202
Q
A
203
Q
A
204
Q
A
205
Q
A
206
Q
A
207
Q
A
208
Q
A
209
Q
A
210
Q
A
211
Q

Describe how a potometer can be used to calculate a more accurate rate of transpiration.

A
212
Q
A
213
Q
A

B

214
Q
A
215
Q
A
216
Q
A

Less uncertainty

Biology - Module 3 (3 decks)

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