theme 4 plants Flashcards
1
Q
plants: components of nucleic acid
A
Nitrogen and Phosphours
2
Q
plants: components of amino acid
A
nitrogen and sulfur
3
Q
plants: function as enzyme cofactors
A
Ca2+
4
Q
plants: role in photosynthesis
A
Mg+2 Fe2+ Fe+3
5
Q
plants: regulation of osmotic potential
A
K+
6
Q
how many essential elements for plants
A
17
7
Q
macronutrients
A
essential in large quantities
8
Q
macronutrients from air and water (not mineral)
A
C H O
9
Q
Macronutrients from mineral nutrients through soil as dissolved ions in water
A
N P K S Ca Mg
10
Q
Micronutrients
A
trace amounts but essential
11
Q
examples of micronutrients imp
A
Cu2+ Cl- Ni2+ (nickle)
12
Q
Nitrogen
A
abundant in air, most limiting to plant, it has to be converted to a usable form.
triple bond requires a specific enzyme.
nitrogen cycle provides soil nitrogen
13
Q
Final:
nitrogen fixation incoperates
A
incorporates atmospheric N2 into plant-available compounds NH4+ with nitrogen fixing bacteria
14
Q
Bacteria ammonification
A
breaks decaying organic N compounds into NH4+, plants take up NH4+ but prefer NO3- (key term)
15
Q
bacterial nitrifcation
A
oxidizes NH4+ to NO3-
16
Q
why do plants convert NO3- to NH4+
A
to assimilate N into organic compounds
17
Q
explain nitrogen cycle fully
A
Nitrogen fixing bacteria converts N2 to NH3 which dissolves to form ammonium NH4+ then undergoes nitrification by nitrifying bacteria to make NO3- nitrate and then NO3- converted to NH4 which is moved via xylem to the shoot system
18
Q
legume root nodules are
A
symbiotic association with nitrogen-fixing bacteria, they fix atmospheric nitrogen, exclusively for legumes, legumes dont need more nitrogen
19
Q
plants grew way taller and posed lodging problems during green revolution
A
.
20
Q
lodging
A
occurs when the crop falls over and does not return to a standing position.
21
Q
1 q on final: eutrophication
A
it is enrichment of an ecosystem with chemical nutrients such as compounds containing N and P, mainly talks about how the cycle of animals start dying in lakes/pods due to usage of chemical nutrients that dissolve in ground water and increase nutrients absorbed by algae so fish begin to die as oxygen levels fall
22
Q
humus
A
decomposing organics, holds water and nutrients
23
Q
there are two relative amounts of soil particles determined properties
A
water and mineral availability
24
Q
water availability
A
soil solution available for plant uptake after gravity drainage, we have coats soil particules, partially fills pore spaces.
sandy soil looser holds less water than clay soils
25
humus relation to water availability
humus increases water availability
26
WILL BE ON FINAL: chlorosis
yellowing of plant tissues due to lack of chlorophyll
27
soil solution
a combination of water and dissolved substances that coats soil particles and partially fills pores spaces, available for plant uptake after gravity drainage(imp last part)
28
water molecules and soil solution
water molecules are attracted by negatively charged clay and humus particles
29
clay is
alkaline
30
mineral availabilty
dissolved in water
passively enter plant roots along with h2o
selectively absorbed by roots via ion-specific transport proteins
31
imp: mineral availability types available in soil solution but not equally available to plants
both cations (Na+, Ca+, Mg+) and anions (NO3-, SO4-2, PO4-3) are present in soil solution, but not equally available to plants
32
extensive root systems are
adaptations to limited mineral nutrients, make up 20-50% of total plant mass, roots grow as long as plants lives.
33
2 q coming: cation exchange
-mineral cations (Mg2+, Ca2+, K+) absorbed to negative soil particles
-cation exchange replaces minerals with H+ produced by roots as excreted H+ or carbonic acid produced by. respiring root cells.
34
2 mechanisms of cation exchange(imp from up)
1st mechanisms, constantly pumped H+ out and Ca2+/K+/Mg2+ taken by root hair.
2nd mechanism, co2 leaves, combines with h2o, forms carbonic acid in soil solution.
35
mineral availability: anions
Anions such as NO3- SO42- PO4- are weakly bound to soil, move freely into root hairs, leach easily by excess water
36
which of the following situation is true for availability of minerals in soil rich in clay with a pH of 8?
a- anions tightly bound to clay while cations can leach out easily
b- anions and cations do not bind to clay and available easily
c- cations and anions are tightly bound to clay and available
d- cations are tightly bound while anions can leach out easily
e- cations and anions leach out easily and are unavailable
d
37
eutrophication is the process by which
a- plants eliminate excess nitrogen
b- plants take up more fertilizers
c- an ecosystem is enriched with excess nitrogen and phosphorous
d- an ecosystem is depleted on nutrients required for its maintenance
e- plants eliminate excess phosphours
c
38
soil usually alkaline with negatively charged clay particles bound to
cations such as ca+ and mg+, anoions are readily available but ca be leached out easily.
when soil turns acidic due to pollution such as acid rain, negative charges on the clay are occupied by h+ and the cations are leached out easily and become unavailable to plants
39
alkaline soils:
anions leach out easily
40
acidic soils
cations leach out easily
41
On final: passive transport
requires no metabolic energy, substances move down a conc or electrochemical gradient.
ex: simple diffusion like H2O, O2, CO2.
ex: transport proteins/facilitate diffusion like ion channels and carrier proteins.
42
on final: active transport:
require metabolic energy ATP.
substances move against gradient
ex: transport proteins using energy like H+/proton pump
43
mechanisms to increase uptake
-root hairs, greatly inc. root S.A, absorbs h2o and minerals
-mycorrhizae, symbiotic association between fungus and plant roots, 2 way exchange of nutrients, plant provides fungus with carbon, fungus increases plant's supply of soil nutrients.
-cuticle and stomata
-membrane transporters on root cell plasma membrane like K+ channel
-charged particules require a channel or transporter
44
charged particles require
a channel or transporter
45
plants concentrate CO2 and use ____ to produce all the food
trace minerals to produce all the food
46
two types of mechanisms plants use for moving water and solutes, both long distance and short distance transport
passive and active transport mechanisms
47
Short distance transport:
into and between cells
to and from vascular tissues
soil to roots
48
long-distance transport
move substance between roots and shoot parts
49
what movement in plants:
osmosis, passive movement of h2o across a selectively permeable membrane
50
aquaporin proteins allow
rapid movement of water through hydrohpbic membrane core
51
water potential
the potential energy of water
driving force, water moves from high h2o potential to low h2o potential
52
water potential of pure water is
0
53
presence of solutes affects water potential in what way
presence of solutes lowers water potential
54
pressure potential
the force required to stop h2o movement, positive pressure increases water potential
negative pressure reduces water potential
55
water potential =
negative water potential plus pressure potential
56
osmosis creates
turgor pressure
57
central vacuole is a ______ that maintains _________
central vacuole is a tonoplast membrane that maintains turgor pressure
58
wilting
when conditions and concentrations are so bad plant cells lose all it's waters
59
wilting occurs when
plants lose more water than they gain, plasmolysis basically.
low potential of dry soil
60
increase in solute inside the cell vacuole will result in
more negative solute potential and more positive turgor pressure inside the systems, so basically increase in solutes will increase pressure potential of the system
61
The water potential 4 in the xyler is suddenly reduced to - 0.5 MPa due to reduced water content in the soil resulting from drought conditions. The solute potential (Y.) inside a
mesophyll cell exposed to this condition = - 0.3 MPa and pressure potential is
(Y,) = 0.1 MPa. What would be the response of the plant cell to this situation to maintain is
turgidity?
A)The plant cell exhibits no net water movement
B)The xylem water potential does not influence the cell's water content
c) water will move from xylem into the plant cell, prior to solute movement into the cell
D)Water will move from the xylem into the plant cell after solute movement into the cell
E) The plant cell will lose all its solutes
D
62
water and solutes travel across the root to the root xylem by two pathways
apoplastic pathway, symplastic pathway
63
apoplastic pathway:
water moves across cortex to endodermis via cell walls and intercellular spaces until casparian stripe, nothing happens in the cell, nothing gets into the cell
64
symplastic pathway:
water flows from cytoplasm of one cell to the next via plasmodesmata, inside the cell.
65
which will be faster route between pathway? will be on final
apoplastic
66
endodermis with casparian strips
screens that filtered and what plants need, once this gets into symplastic no need for screening by endodermis
67
nutrients movement through both
apoplast (passively uptaken by roots) and symplast pathway (actively + passively uptaken)
68
endodermal cells act
as a selective barrier so ions are actively transported ATP into xylem
69
casparian strip in root endodermis forces
apoplastic water and nutrients into symplast, everything switches to symplastic.
70
casparian strips ensures that
all water and solutes pass through a plasma membrane in order to enter a vasculature, allowing plants to regulate the ions that pass into the vascular tissue (imp)
71
casparian strips in roots prevent
water from moving through cells
72
casprian strips are in
endoderm
73
casprian strips act as a
selective barrier for ions
74
casprian strips restricts
solutes from flowing back
75
leaf anatomy contributes to
cohesion-tension forces, tallest trees have cohesion-tension mechanism may reach its physical limit
76
root pressure contributes
to upward water movement in some plants
77
stomatal movements regulate
the loss of water by transpiration
78
mechanical properties of water
transpiration and cohesion-tension mechanisms
79
transpiration
evaporation of water out of plants, greater than water used in growth and metabolism
80
cohesion-tension mechanism
evaporation from mesophyll walls, replacement by cohesion H-bonded water in xylem, tension, negative pressure gradient, adhesion of water to xylem walls adds to tension
81
cohesion tension mechanism is driven by
transpiration
82
effects of negative pressure on the column: what helps resist this?
lignin secondary cell wall
weight of the column
adhesive forces in xylem
83
leaf anatomy key to processes
moving water upward in plants
84
leaves facilitate
transpiration as:
-large volume of air space provides SA for evaporation
-stomata: thousands to millions of stomata
-short cell distances to xylem: each square cm contains thousands of xylem veins
memorize the thousands of the last two
85
root pressure
positive pressure in roots that force xylem sap upward, occurs in high humidity or low light and moves water up short distances
86
guttation (in final)
when root pressure is strong enough to force water out of leaf openings, water is pushed up and out of veins
87
Transolaction might be in short free resoponse
how plants move sugars.
long-distance transport of substances via phloem
multi-directional (xylem is unidirectional and only up stream)
88
might be in short free resoponse
phloem sap (water and organic compounds) flow through
sieve tubes, phloem sap contains more than just sugars.
amino acids, organic acids, organic nitrogen compounds, hormones, and other signal molecules.
89
might be in short free resoponse
differences in pressure between source and sink regions drive
the flow
90
source
any region of plant where organic substances are loaded into phloem, ex: mature leaves
91
sink
any region of plant where organic substances are unloaded from phloem, ex: growing tissues and storage regions
92
roots can act as
source or as sinks
93
in spring, roots are
the source and leaves are sinks, in winter all nutrients are stored in sink
94
phloem made out of
sieve tubes + companion cells
95
sieve tubes are
alive at maturity but undergo partial programmed cell death
96
sieve plates are
modified cell walls with plasma membrane lined pores
97
sieve tubes are
connected to companion cells that play a life-supporting role
98
features of mature sieve elements present (know for exam)
plasma membrane, plastids, mitochondria, Smooth ER
99
mechanisms of sugar loading
both apoplastic and symplastic
100
unloading of sugar is mostly
symplastic
101
loading at a source
in leaves, surcose is actively loaded into phloem (into sieve tubes)
102
more surcose loaded into the sieve tubes means
low water potential
103
watch slide 58 animation
104
pressure flow mechanism moves
substances by bulk flow under pressure from sources to sinks based on water potential gradients.
load from source -> transport in sieve tube -> unload into sinks
105
bulk flow from source to sink
more sucrose in the sieve tubes, low water potential, so influx of water increases pressure in the sieve tubes, sap flows in bulk toward the sink (lower pressure), so sucrose is unloaded into sink cells.
106
like animals, gas exchange by
simple diffusion
107
to maximize the rate of diffusion,
short distance between cells and external environment, thin layered leaf, gas-filled space within leaves,
large leave area
108
stomata
an aperture on epidermis of a leaf, mostly lower epidermis
109
stomata consist of two specialized cells
guard cells that surround a tiny pore called a stoma
110
co2 uptake results in
water loss, co2 enters and o2 exit leaf through opening stomata.
water vapor will exit the leaf along a diffusive gradient
111
K+ is mostly in guard cell during
open stomata
112
K+ is mostly in epidermal cells during
closed stomata
113
stoma is open,
water and solute have moved in
114
stoma is closed,
water and solutes have moved out. ABA signal shuts down stoma
115
turgid stomata is
open
116
flaccid stomata is
closed
117
2 quesitons coming at least: closed stomata has 0 um of stomatal aperture, 1MPa guard cell turgor, K+ content 0.3 pmol vs open stomata with 8 um stomatal aperture, 4.5 MPa guard cell turgor, 2.5 pmol guard cell turgor
