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Biology (NCERT) - Class XI > XI Chap 11 Transport in Plants > Flashcards

XI Chap 11 Transport in Plants Flashcards

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1
Q

___________ won the Nobel Prize in 1961 for mapping of the pathway of carbon assimilation in photosynthesis

A

Melvin Calvin

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2
Q

Principles of photosynthesis as established by Melvin Calvin are being used in studies on ______________

A

renewable resources

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3
Q

Plants are much smaller than animals and hence do not need to move molecules over very long distances. T or F?

A

False, they have to move them over very long distances.

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4
Q

Plants have a circulatory system to transport nutrients and water. T or F?

A

False, They do not have circulatory system.

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5
Q

Photosynthates are ________

A

food synthesized by plant leaves

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6
Q

In a flowering plant, what substances need to be transported?

A

water
mineral nutrients
organic nutrients
plant growth regulators

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7
Q

Over small distances, substances in plants move by _______, ______ and _________

A

diffusion, cytoplasmic streaming and active transport

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8
Q

Over long distances, substances are transported through __________

A

vascular system (xylem and phloem)

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9
Q

What is translocation?

A

Bulk movement of substances
conducting/vascular tissues
long distances
in plants

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10
Q

In rooted plants, transport of ___________ is unidirectional and of ____________ is multidirectional

A

water and minerals - unidirectional

organic and mineral nutrients - multidirectional

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11
Q

How are hormones or growth regulators transported?

A

very small amounts,

sometimes in strictly polarised or unidirectional manner

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12
Q

Movement by diffusion is active or passive?
Slow or fast?
Energy requiring or not?

A

Passive, slow, no energy expenditure

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13
Q

Diffusion is dependent on living system. T or F?

A

False

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14
Q

Diffusion ___ solids is more likely rather than ___ solids

A

in solids more likely than of

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15
Q

_______ is the only means for gaseous movement within the plant body

A

Diffusion

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16
Q

A ________ must already be present for diffusion

A

gradient

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17
Q

Smaller substances diffuse fast or slow?

A

Fast

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18
Q

Diffusion across a membrane depends on _________

A

solubility in lipids, soluble => diffuse faster

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19
Q

Substances that have a ________ find it difficult to pass through membrane

A

hydrophilic moeity

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20
Q

What is facilitated diffusion

A

membrane proteins provide sites for hydrophilic molecules to cross the membrane

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21
Q

Facilitated diffusion occurs against the gradient. T or F?

A

False, occurs along the gradient, just at specific sites

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22
Q

Facilitated diffusion requires ATP. T or F?

A

False

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23
Q

When does transport rate reach maximum in facilitated diffusion?

A

When all of protein transporters are being used (saturation)

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24
Q

Facilitated diffusion is non-specific. T or F?

A

very specific, only allows select substances for uptake

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25
Q

Why is facilitated diffusion sensitive to inhibitors?

A

They react with protein side chains

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26
Q

Proteins form ____ in the membrane for molecules to pass through in facilitated diffusion

A

channels

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27
Q

Protein channels can be open or ______

A

controlled

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28
Q

A porin is ______

A

a protein that forms large pores in outer membrane of plastids, mitochondria and some bacteria allowing molecules up to the size of small proteins to pass through

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29
Q

Transport/carrier protein rotates to transport a molecule from the outside to the inside. T or F?

A

True

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30
Q

Water protein channels are made up of ___ different types of _______

A

8, aquaporins

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31
Q

What are the 3 types of transport proteins?

A
  1. Symport - 2 types of molecules move together (same direction)
  2. Antiport - 2 types of molecules move in opp. directions
  3. Uniport - one molecule moves across
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32
Q

What is active transport?

A

against a concentration gradient (low to high / uphill), requires energy

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33
Q

What are pumps?

A

Proteins that use energy to carry substances across membrane (uphill)

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34
Q

Like enzymes, carrier proteins are very specific. T or F?

A

True

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35
Q

What’s common and what’s different in

Simple vs Facilitated diffusion?

A

Common: along gradient so

  • downhill transport
  • does not require ATP

Simple diffusion - no proteins, not selective, no transport saturation (all true for facilitated)

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36
Q

What’s common and what’s different in

Active transport vs Facilitated diffusion?

A

Common: both use proteins hence

  • highly selective
  • transport saturates
  • respond to inhibitors
  • under hormonal regulation

Active transport - uphill transport, energy required

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37
Q

_______ is essential for all physiological activities of the plant

A

Water

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38
Q

______ provides the medium in which most substances in living organisms are dissolved.

A

Water

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39
Q

Protoplasm of the cells is nothing by _____

A

water

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40
Q

Watermelon has over _____% water

A

92%

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41
Q

Most herbaceous plants have only about _______ percent of its fresh weight as dry matter

A

10-15%

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42
Q

Woody parts have the most water in plants. T or F?

A

False, woody parts - very little water,

soft parts - water

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43
Q

Seed is dry i.e. it does not contain water. T or F?

A

False, it still has water even though dry

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44
Q

_________ plants take up a huge amount of water but most of it is lost to the air through process called ___________

A

Terrestrial plants, transpiration

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45
Q

In transpiration, plants lose water through evaporation from _______

A

the leaves

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46
Q

A mature corn plant absorbs _____ litres of water in a day

A

3 L

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47
Q

Mustard plant absorbs how much water?

A

equal to its own weight in 5 hours

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48
Q

__________ is often the limiting factor for plant growth and productivity in both agricultural and natural environments

A

Water

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49
Q

_______ and _______ are the two main components that determine water potential.

A

Solute potential and pressure potential

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50
Q

Water molecules possess _________ energy

A

Kinetic

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51
Q

In liquid and gaseous form, water molecules are in _________ motion that is both ______ and _______

A

random, rapid, constant

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52
Q

Greater the concentration of water in a system, the greater is its ________ or _________

A

kinetic energy or water potential

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53
Q

Pure water will have the lowest water potential. T or F?

A

False, highest

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54
Q

Water moves from system containing _____ water potential to _______. This is aka ________

A

higher; lower

diffusion

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55
Q

Water potential is denoted by the Greek symbol _____

A

Psi Ψ

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56
Q

Water potential is expressed in units such as _______

A

pascals (Pa)

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57
Q

Water potential of pure water at standard temperatures which is not under any pressure is taken to be _____

A

zero

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58
Q

How does solute reduce water potential?

A

Dissolved => solution has fewer free water molecules => free energy/concentration of water decreases

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59
Q

All solutions have higher water potential than lower water. T or F?

A

False, lower

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60
Q

Ψs (solute potential) is always ___________

A

negative

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61
Q

Solution at atmospheric pressure, what is the relation between Ψw and Ψs

A

Ψw = Ψs

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62
Q

At atmospheric pressure, Ψp is _____

A

0

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63
Q

If a pressure greater than atmospheric pressure is applied, Ψw decreases or increases?

A

increases

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64
Q

Pumping water from one place to another is an example of ___________

A

increasing pressure => water potential increases

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65
Q

When water enters a plant cell by diffusion, ________ is built up against the cell wall and makes the cell _________. One can say pressure potential in this cell has ________

A

pressure, turgid;

increased

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66
Q

Pressure potential is positive or negative?

Solute potential is positive of negative?

A

Pressure - usually positive (can be negative in plant xylem)

solute - negative

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67
Q

Relationship between Ψs Ψw Ψp

A

Ψw = Ψs + Ψp

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68
Q

Cell wall is freely permeable to water and substances in solution. T or F?

A

True

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69
Q

In plant cells, ____________ contributes to the solute potential of the cell

A

vacuolar sap

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70
Q

Which two membranes determine movement of molecules in or out of the cell?

A

Cell membrane

Vacuole membrane i.e. tonoplast

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71
Q

Osmosis specifically refers to the diffusion of ________

A

water

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72
Q

Osmosis occurs spontaneously in response to a ______________

A

driving force

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73
Q

The net direction and rate of osmosis depends on both _____ gradient and ______ gradient

A

pressure and concentration

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74
Q

Water moves from region of ______ chemical potential to _____ chemical potential

A

higher to lower

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75
Q

_________ is the pressure required to prevent water from diffusion into a solution.

A

Osmotic pressure

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76
Q

The more the solute concentration, the _______ the osmotic pressure has to be

A

greater

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77
Q

Osmotic pressure is equal to osmotic potential. T or F?

A

False, numerically equivalent but signs are opposite

positive osmotic pressure => osmotic potential is negative

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78
Q

Isotonic vs. hypotonic vs. hypertonic?

A

Isotonic - external solution balances osmotic pressure of cytoplasm

Hypotonic - external solution dilute

Hypertonic - external solution more concentrated

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79
Q

How do cells react in hypotonic vs hypertonic solutions?

A

Hypotonic - water enters, cell swells, cytoplasm builds pressure against wall, turgid

Hypertonic - water leaves (cytoplasm then vacuole), protoplast shrinks away from walls, “plasmolysed”

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80
Q

How do cells react in isotonic solution?

A

no net flow of water, cells are flaccid

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81
Q

Process of plasmolysis is irreversible. T or F?

A

False, reversible

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82
Q

What is turgor pressure?

A

When cytoplasm builds up pressure against cell wall due to water diffusing into the cell (hypotonic solution)

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83
Q

Why does cell not rupture in a hypotonic solution?

A

due to rigidity of cell wall

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84
Q

Pressure exerted by the protoplasts against rigid cell walls due to entry of water is called _______________

A

pressure potential Ψp

85
Q

___________ is ultimately responsible for enlargement and extension growth of cells

A

Turgor pressure

86
Q

___________ is a special type of diffusion where water is absorbed by solids / colloids

A

Imbibition

87
Q

What are the classical examples of imbibition?

A

Seeds and dry wood

88
Q

Pressure produced by swelling of wood due to water has been used by prehistoric man to ____________

A

split rocks and boulders

89
Q

Imbibition is also diffusion. True or False? Explain.

A

True, since water movement is along a concentration gradient

90
Q

In imbibition, in addition to water potential gradient, affinity between _____ and _____ is a pre-requisite.

A

adsorbant and liquid

91
Q

Typical plant cell size

A

50μm

92
Q

Movement of a molecule across a typical plant cell (50 μm) takes how long?

A

2.5 seconds

93
Q

At typical rate of movement of molecule in plant cell, how long would it take for movement of molecules over distance of 1m by diffusion along?

A

2 years

94
Q

Water and minerals, and food are generally moved in plants by a _______ system

A

mass / bulk flow system

95
Q

_________ is the movement of substances in bulk or en masse as a result of ________ differences between 2 points

A

Mass flow, pressure differences

96
Q

In mass flow, different substances are swept along at different paces like in diffusion. T or F?

A

False,

like flowing river - same pace for all substances in mass flow;
in diffusion, different paces depending on gradients

97
Q

Bulk flow can be achieved through _______ or ________ gradients. Give examples.

A

positive hydrostatic pressure gradient (garden hose) or

negative hydrostatic pressure gradient (suction through straw)

98
Q

_____ plants have highly specialized vascular tissues

A

Higher plants

99
Q

Xylem is associated with the translocation of ________________ from roots to the aerial parts of plants.

A

mainly water, mineral salts;

some organic nitrogen and hormones

100
Q

Phloem translocates a variety of organic solutes (but not inorganic) mainly from the leaves to other parts of the plant. T or F?

A

False, organic and inorganic solutes

101
Q

Responsibility of absorption of water and minerals is the function of ________

A

root hairs

102
Q

How many root hairs typically in root tips of plant?

A

Millions

103
Q

What are root hairs?

A

Thin-walled slender extensions of root epidermal cells

104
Q

Root hairs increase ______________ for absorption

A

surface area

105
Q

Water + mineral solutes are absorbed by root hairs by process of ________

A

diffusion

106
Q

Two pathways for water in roots?

A

Apoplast and symplast

107
Q

Apoplast is a system of __________ while symplast is a system of __________

A

apoplast - adjacent cell walls

symplast - interconnected protoplasts

108
Q

Continuous layer of cell walls throughout the plant is broken by _______

A

casparian strips of endodermis

109
Q

Movement across apoplast involves intercellular spaces, walls of the cells, and across the cell membrane. T or F?

A

False, first two correct. does NOT cross cell membrane

110
Q

Apoplast movement is dependent on _________

A

gradient

111
Q

Apoplast does not provide any barrier to water movement and movement is through mass flow. T or F?

A

True

112
Q

Why does mass flow of water occur in apoplast pathway?

A

Adhesive and cohesive properties of water, and tension developed in continuous stream of water as water evaporates into intercellular spaces or atmosphere

113
Q

In symplast pathway, neighboring cells are connected through ____________ that extend through the _________

A

cytoplasmic strands, plasmodesmata

114
Q

In symplastic movement, water travels within cells through _______ and across cells through ________

A

cytoplasm, plasmodesmata

115
Q

Water movement is faster or slower in symplastic system? Why?

A

Slower, because it has to enter through cell membrane

116
Q

Water movement in apoplast and symplast pathways are along a gradient. T or F?

A

True

117
Q

Symplastic movement is aided by ____________

A

cytoplasmic streaming

118
Q

Movement of chloroplast in cells of Hydrilla leaf is an example of?

A

Cytoplasmic streaming

119
Q

Most of water flow in roots occurs via _________

A

apoplast

120
Q

Most of water flow in roots occurs through apoplast since …?

A

cortical cells are loosely packed and hence no resistance to water movement

121
Q

The inner boundary of the cortex called the _________ is impervious to water because of ____________

A

endodermis, casparian strip (band of suberised matrix)

122
Q

At the endodermis, water moves through ______ (apoplast/symplast) and crosses a membrane again to reach ______

A

symplast, xylem

123
Q

Water movement in the root layers in the epidermis is ultimately ________

A

symplastic

124
Q

Once inside the xylem, water is free to move apoplastically or symplastically?

A

Both

125
Q

In young roots, water enters directly into _______, which are non-living conduits and so are part of the _________

A

xylem vessels and/or tracheids, apoplast

126
Q

________ is a symbiotic association between fungus and root system

A

Mycorrhiza

127
Q

Fungal filaments in mycorrhiza form a ______ around the young root or they ________

A

network; penetrate root cells

128
Q

Hypae have a very large ________ in mycorrhiza that absorb ______ and _____ from soil, much better than roots can

A

surface area, water and mineral ions

129
Q

In mycorrhiza, plants provide _______ and ______ to fungus.

A

sugars, N-containing compounds

130
Q

Some plants have an obligate association with the mycorrhizae. T or F?

A

True

131
Q

Pinus seeds cannot germinate and establish without the presence of __________

A

mycorrhizae

132
Q

Water movement into roots is active or passive?

A

Passive

133
Q

What is root pressure?

A

Water follows pressure gradient and increases pressure inside the xylem

134
Q

__________ is responsible for pushing up water to small heights in the stem

A

Root pressure

135
Q

Effects of root pressure are observable at night and early morning when _______ is low; excess water collects in form of droplets around ___________ near tips of leaves / grass blades.

A

evaporation; special openings of veins

136
Q

What is guttation?

A

Water loss in liquid phase due to root pressure, visible at night / early morning when evaporation is low

137
Q

Root pressure places a major role in upwards water movement in tall trees as evidenced by guttation. T or F?

A

False, only modest role, transpiratory pull required for major upwards movement

138
Q

Greatest contribution of root pressure is ________

A

re-establish continuous chains of water molecules in xylem which break due to transpiration

139
Q

Upwards movement of water in plants can go as fast as _________

A

15 meters per hour

140
Q

Water is mainly ‘pulled’ through plant, driving force being transpiration from leaves. What is this model of water transport called?

A

Cohesion-tension-transpiration pull model

141
Q

Less than ______ of the water reaching leaves is used in photosynthesis. Most of it is lost through ____ in the leaves

A

1%

stomata

142
Q

What is transpiration?

A

evaporative loss of water through stomata

143
Q

Besides transpiration, exchange of _____ and ______ in leaf also occurs through stomata

A

oxygen and carbon dioxide

144
Q

Normally stomata are open in the ______ and closed in the ______

A

day; night

145
Q

Immediate cause of opening or closing of stomata is a change in __________

A

turgidity of the guard cells

146
Q

Inner wall of each guard cell, towards the pore, is _____ and ______

A

thick and elastic

147
Q

When turgidity (increases / decreases) in flanking guard cells, think outer walls _______ and force the _______ into a crescent shape

A

increases,
bulge out,
inner walls

148
Q

How many guard cells flank stomata?

A

2

149
Q

Opening of stomata is aided due to the orientation of ____________ in the cell walls of the guard cells. Cellulose microfibrils are oriented ________ rather than ________.

A

microfibrils,

radially rather than longitudinally

150
Q

When turgidity (increases / decreases) in flanking guard cells due to _________, elastic inner walls regain original shape, guard cells become _____ and stoma closes.

A

decreases,
water stress / loss,
flaccid

151
Q

Lower surface of a monocot leaf has greater number of stomata. T or F?

A

False, dicot leaf

152
Q

Dorsiventral leaf has greater number of stomata in ______ while isobilateral leaf has ________

A

lower surface, equal on both surfaces

153
Q

Transpiration is affected by what internal (plant) factors

A

number and distribution of stomata,
percent of open stomata,
water status of plant,
canopy structure

154
Q

Transpiration is affected by what external factors

A

temperature,
light,
humidity,
wind speed

155
Q

Transpiration driven ascent of xylem sap depends mainly on what properties of water?

A

Cohesion, Adhesion and Surface tension

156
Q

What is cohesion property of water?

A

mutual attraction between water molecules

157
Q

What is adhesion property of water?

A

attraction of water molecules to polar surfaces

158
Q

What is surface tension property of water?

A

water molecules are attracted to each other in the liquid phase more than gas phase

159
Q

Cohesion, Adhesion and Surface tension give water high __________ and high ______

A

tensile strength, capillarity

160
Q

Tensile strength and Capillarity are?

A

tensile strength - ability to resist a pulling force,

capillarity - ability to rise in tubes

161
Q

In plants, _______ is aided by the small diameter of tracheids and vessel elements,

capillary or tensile strength?

A

Capillary

162
Q

Forces generated by transpiration can create pressures sufficient to lift a xylem sized column of water over _______ meters high

A

130

163
Q

Five functions of transpiration?

A
  1. creates pull for absorption and transport
  2. supplies water for photosynthesis
  3. transports minerals from soil to all parts of plant
  4. cools leaf surfaces
  5. maintains the shape an structure of plants (cells kept turgid)
164
Q

Evaporative cooling due to transpiration cools leaf surfaces by how many degrees?

A

10-15 degrees

165
Q

Evolution of ___ photosynthetic system is a strategy to maximize the availability of ____ while minimizing loss of _____

A

C4, CO2, water

166
Q

C4 plants are _____ as efficient as C3 in fixing CO2 and loses only ______ as much water as C3 plant for same amount of CO2 fixed.

A

twice as efficient,

halve as much water

167
Q

Plants obtain their carbon and most of their oxygen from _____ in the atmosphere

A

CO2

168
Q

All minerals can be passively absorbed by roots. T or F? Explain.

A

False, not all

  • charged ions cannot move across cell membranes
  • concentration in soil is lower than in roots
169
Q

Most minerals enter the root through what process? Does it require energy?

A

Active absorption. Yes.

170
Q

Active uptake of ions is partly responsible for the _______ gradient in roots, and therefore also responsible for ______

A

water potential gradient,

osmosis

171
Q

Mineral ions are absorbed from soil by both passive and active transport. T or F?

A

True

172
Q

Unlike all cells, endodermal cells have many transport proteins embedded in plasma membrane. T or F?

A

False, LIKE all cells, rest is correct

173
Q

Transport proteins of endodermal cells are ________ where a plant adjusts the quantity and types of solutes that reach xylem.

A

control points

174
Q

Root endodermis because of the layer of _____ has the ability to actively transport ions in _____ direction(s) (how many?)

A

suberin, one direction only

175
Q

Chief sinks for the mineral elements are _________

A

growing regions of plant - apical and lateral meristems, young leaves, developing fruits/flowers/seeds and storage organs

176
Q

Unloading of mineral ions at sinks occurs at the ________ through ____ and ____ processes

A

fine vein endings;

through diffusion and active transport

177
Q

Mineral ions are frequently remobilized from older to younger parts of the plants. T or F?

A

True

178
Q

Mineral ions, like calcium, are frequently remobilized from older to younger parts of the plants. T or F?

A

False, structural components like calcium are not remobilised

179
Q

Before leaf fall in deciduous plants, minerals like ____________ (4) are moved to other parts.

A

phosphorus, sulphur, nitrogen and potassium

180
Q

Some of the nitrogen travels as ____, most of it is carried in form of ______

A

some - inorganic ions,

most - organic form, amino acids and related compounds

181
Q

Small amounts of ____ and ____ are carried as organic compounds

A

phosphorus and sulphur

182
Q

No exchange of materials takes places between xylem and phloem as they are two separate transport systems. T or F?

A

False, small exchange does take place

183
Q

Xylem only transports inorganic nutrients while phloem transports only organic. T or F?

A

False, small exchange takes place.

184
Q

Food in plants is transported by phloem from _____ to ______

A

source to sink

185
Q

Source and sink may be reversed depending on season or plants needs. T or F?

A

True

186
Q

In early spring, ___ acts as sink and ___ as a source.

A

buds of trees - sink

roots - source

187
Q

Direction of movement in the phloem and xylem?

A

Phloem - can be upwards or downwards i.e. bidirectional

Xylem - upwards only i.e. unidirectional

188
Q

Phloem sap mainly constitutes _____ and _____, but other substances like _____, _____ and ______ are also translocated

A

water and sucrose;

sugars, hormones, amino acids

189
Q

What is the pressure flow hypothesis?

A

Accepted mechanism for translocation of sugars.
Sugar (sucrose) prepared at source -> moved into companion cells -> living phloem sieve tube cells (active transport) -> hypertonic condition in the phloem -> osmosis from adjacent xylem into phloem -> osmotic/hydrostatic pressure pressure builds up in the phloem -> sap moves up and into the cells that use the sugar

190
Q

Sugars are converted in to ____ by plant cells that use it

A

energy, starch or cellulose

191
Q

As sugar is unloaded from phloem, the osmotic pressure _______ (increases/decreases) and water moves ______ (into/out of) phloem

A

decreases, out of

192
Q

Food is actively transported in the phloem. T or F?

A

True

193
Q

Loading of phloem sets up a _______ potential gradient that facilitates mass movement in phloem

A

water

194
Q

Phloem tissue is composed of _____ which form long columns with holes in their end walls called ______

A

sieve tubes, sieve plates

195
Q

_________ pass through the holes in the sieve plates forming continuous filaments

A

Cytoplasmic strands

196
Q

Incoming sugars are ________ (actively/passively) transported out of the phloem and removed as __________

A

actively, complex carbohydrates

197
Q

When sugars leave sieve tubes at sinks, water follows by ________

A

osmosis

198
Q

When sugar enters sieve tubes at source, water follows by osmosis and creates high _______ pressure

A

turgor

199
Q

Sugar solution in phloem flows from regions of ______ turgor pressure to _______ turgor pressure

A

high to low

200
Q

In the root, sugars leave sieve tube for _____ and ______

A

metabolism and storage

201
Q

A simple experiment called _______ was used to identify the tissue through which food is transported and to show that transport takes place only in one direction.

A

girdling

202
Q

Explain girdling

A

On tree trunk, remove ring up bark up to a depth of phloem layer. Downward movement of food cannot happen beyond that point, stem above ring becomes swollen after few weeks.

203
Q

Plants obtain a variety of inorganic elements and salt from _____ and ______

A

water and soil

204
Q

Passive transport is always entropy driven. T or F?

A

True

205
Q

Diffusion of substances depends on two factors

A
  1. size

2. solubility in water / organic solvents

206
Q

Osmosis depends on ____ and _____ gradient

A

pressure and concentration

207
Q

Excess water is removed through tips of leaves of plants by ________

A

guttation

208
Q

The source-sink relationship is variable. T or F?

A

True

Biology (NCERT) - Class XI (23 decks)

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