Plants Flashcards
1
Q
what do plants produce
A
*Food
*Natural Products (O2, ozone, coal, oil, gas, wood, paper, medicine, limestone etc.)
*Ecosystem services (ex. protection from erosions or environmental disasters)
2
Q
what two influential scientific inquiries were made using plant models?
A
Genetics: Mendel pea plants
Transposons: McClintock corn plants
3
Q
when did aquatic plants invade land
A
475 million years ago (Ma)
4
Q
what made it difficult for aquatic plants to go on land
A
*cells drying out
*physical support on land (air less dense than water)
* harder for sperm to swim-> sexual fertilization/ reproduction
5
Q
land advantage over water for plants
A
less competition for light on land
6
Q
green algae and land plant shared traits
A
- cellulose cell wall
- chlorophyl a and b
-sperm with 2 anterior (front) flagella
*shared common ancestor
7
Q
preadaptations
A
trait already present that allowed for major ecological transition
*aquatic plants to land plants
8
Q
preadaptations of chlorophytes
A
- fresh water habitat; live on edges of pond so as water level fluxuates -> half aquatic and half land
-life cycle that allows dispersal by wind using spores
9
Q
zygotic meiosis
A
Life cycle of Chlorophylls: multicellular algae (haploid) produces diploid zygote which undergoes meiosis and produces 4 haploid spores
10
Q
sporopollenin
A
(most stable) biopolymer that covers spores; uv protectant, dehydration resistant, decay resistant
11
Q
how did first land plants get nutrients with no soil
A
associated with mycorrhizal fungi to help get nutrients from the bedrock
12
Q
4 main adaptations of land plants
A
cuticle, pores, stomata, embryo
13
Q
cuticle
A
upper layer on plants that reduces water loss and gas exchange
14
Q
Pores
A
hole in cuticle to help with gas exchange; water loss
15
Q
Stomata
A
mechanism that helps pores open and close to control gas and water exchange based on environment/needs
16
Q
Embryo
A
young sporophyte that is nourished by maternal tissue
17
Q
Gametophyte
A
-haploid
-makes gametes by mitosis
18
Q
Sporophyte
A
- diploid
-makes spores (haploid) by meiosis
19
Q
Bryophytes
A
-includes liverworts, mosses and hornworts
-live in moist understories of forest
-very short (no vascular system)
-gametophytes are dominant life stage
20
Q
Liverworts
A
-pores (NO STOMATA)
-look like earlies land plants
21
Q
Mosses
A
-have stomata
-economically important for florist trade and making Peat (fuel and alcohol flavoring)
22
Q
Hornwart
A
long living
23
Q
Where are the sporophytes on Bryophytes
A
saprophytes stem up from the gametophyte base and perform meiosis to make spores
24
Q
why did plants get taller/ develop vascular systems
A
to be taller than competitors
25
vascular system transfers
water from root -> leaves
sugars from leaves -> root and stems
26
do saprophytes, gametophytes or both have vascular systems?
ONLY sporophytes evolved vascular systems; sporophyte dominance
27
Ferns
-dominant life stage: sporophytes (diploid)
-gametophyte and sporophyte grow independently; do their own photosynthesis
28
what are ferns categorization
seedless vascular plants
29
vascular plants with seeds
gymnosperms and angiosperms
30
4 divisions of gymnosperms
ginkgoinae, cycads, gnetidae, conifers
31
Gymnosperms: ginkgoinae
stinky coding on seeds
32
Gymnosperms: cycads
-look like palm tree
-very endangered due to climate
33
Cycad conservation efforts
use oxygen isotope that i geographically distinct to see if tree is native to area or was poached and bought
34
Gymnosperms: Gnetidae
-only grows 2 leaves from middle stem
- leaves fray as plant grows old
35
Gymnosperms: Carnifers/ pinidae
- pine and fur trees
-largest by volume plant
36
Angiosperms
-most diverse and successful group of land plants
-produce fruit and flowers
-double fertilization
-seeds enclosed in sporophyll
37
sporophyll
leaf modified for reproduction
ex. flower petals are leaves that evolved for reproductive function
38
types of seed plants
gymnosperms and angiosperms
39
order of trait evolution for land plants
1. alternating generation (gametophyte and sporophyte)
2. stomata
3. long lived sporophyte (dominant life form)
4. vascular system
5. seeds
6. flowers
40
evolution of land plants: dominant life stage
started with gametophytes as dominant life stage (bryophytes) -> gametophytes and sporophytes being independent (ferns and seedless land plants) -> dominant sporophyte (seed plants)
41
how do seed plants reproduce
Spores are NOT DISPERSED; spores held onto by female gametophyte and fertilized by male gametophyte (pollen grain)
42
pollination
male gametophyte moves to female gametophyte -> fertilization
43
gymnosperm seeds
naked seed (no sporophyll coding); pollen delivers directly to ovule
44
ovule
structure of sporophyte in which female gametophyte + egg develops
45
angiosperm seed
hidden seed; ovule encased in sporophyll called carpal where pollen is delivered to
46
why are seeds more beneficial than spores
- can remain dormant and disperse when favorable by environmental conditions
-build in food for seeds in embryo
-targeted dispersal by animals; not just dispersed by wind
-invest more in fertilized ovules -> more resources for next generation of sporophytes
47
spores in seed plants
spores are not dispersed and become gametophytes while still on sporophyte
48
what are fruits
structures derived from carpal tissues; derived from ovary that encloses seeds
*only in angiosperms
49
what is the female gametophyte called
pistil
(includes ovary + style + stigma/landing pad for pollon)
50
pistil structure
*8 nuclei; 7 cells
*large center cell with 2 polar nuclei
51
what is the male gametophyte called
stamen
52
male gametophyte structure
anther (sporophyte where pollen grains produced) held out by fillimants
53
what does a spore turn into
a gametophyte through mitosis
54
what does an egg turn into
a zygote by fertlization
55
what does an ovule turn into
a seed by fertilization
56
what do ovaries/ carpal tissue turn into
fruit through fertilization
57
Pollination
mechanism that promotes transfer of pollen from antlers to the stigma; animals and wind pollinate
58
how does the pollen find the ovule to make a seed
the ovule produces chemical attractants that the pollen tube (growing out of the pollen grain) goes towards
59
double fertilization
2 polar nuclei in ovule fuse with 1 sperm to make a triploid endosperm
60
endosperm
nutritive tissue that supports the embryo
61
germination: digot vs monogot
2 vs 1 cotyledon (an embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed)
62
Apical Buds
bud on branch or root tip
63
Axillary Bud
bud at node/intersection of 2 plances
64
meristem tissue
tissue that can differentiate into other types of tissue; produces primary growth
65
primary growth
elongates shoots and roots; enables plants to grow in length and branch
66
repeating units of shoots
nodes and internodes
67
how is plant growth different than animal growth
plant growth is indeterminate(no end)
68
3 zones for root primary growth
root cap: zone of cell divison -> zone of elongation -> zone of differentiation: top of soil
69
as roots grow, how do the zones shift
the zones shift down towards the root cap; all of the new cell formation and development is happening at the bottom of the root
70
primary growth: 3 tissue types
-dermal (outside layer of cell)
-vascular (transport tissue)
-ground (all other tissues)
71
what dermal tissue surrounds primary roots and shoots
epidermis
72
primary root ground tissue
cortex and endodermis
73
vascular bundle
in the center of the root; transports water and nutrients through plant; made of xylem and phloem.
74
difference between dicots and monocots
dicots undergo secondary growth and monocots do not
75
difference between dicots and monocots shoot structures
dicots: vascular bundles form ring around edge; separate pith(middle) and cortex(outer)
monocots: have no differentiation of ground tissue and have vascular bundles spread all around
76
bundle-sheath cells
ring of ground tissue around the vascular tissue (xylem and phloem -> vascular bundle)
77
how is the cuticles made
produced by the epidermis
78
secondary growth
growth in plant diameter; only after elongation is complete
79
what cells allow for secondary growth
lateral meristems; vascular cambium and cork cambium
80
what cells allow for primary growth
apical meristems
81
vascular cambium
source of new xylem and phloem (inner layer)
82
what is wood
xylem produced by secondary growth
83
cork cambium
outer layer; protection of plant
84
what produced bark
cork cambium; all material outside of vascular cambium
85
what causes increase of girth in trees/plants
increased production of xylem; secondary phloem pushed outward by formation of new xylem
86
why might branches have less growth rings than the trunk of a tree
branches newer than trunk of the tree -> less growth rings
87
Tropism
growth response that results in curvature of the whole plant organism
88
positive tropism
curvature towards the stimulant
89
negative trpism
curvature away from the stimulant
90
chemotropism
Stimulus is a chemical in the environment; ex. chemical ovule produces so pollen tube goes to it
91
gravotropism
direction of growth based on gravity
shoots: negative gravitropism (up)
roots: positive gravitropism (down)
92
Heliotropism
bud tracks sun; ex. sunflowers
93
Thigmotropism
sense structure and wrap around/ grow on it; ex. vines on a building
94
phototropism
growth towards or away from light
95
what protein is stimulated by sunlight -> signal transduction pathway
phototropin
96
when is phototropin inactive
in the shade
97
where is phototropin located
in the tip of a growing plant
98
differential activation
some phototropins active (in sun) and some not (in shade)
* when sunlight comes from side/ angle
99
what plant hormone is constantly made while the tip is activity growing; shoot -> root
auxin; normally distributed equally down stem -> root
100
what happens to axuin when light comes from the side
auxin only travels down dark side of the stem causing only that side to elongate
101
what is auxins function
cell elongation
102
Acid growth hypothesis
auxin binds to receptor and triggers signal transduction cascade -> loosening cell walls -> osmosis draws water in -> cell elongation
103
how does the cell wall loosen
auxin binds to receptor that activated proton pumps
-> cell wall becomes more acidic
-> activates expansions
-> loosening enzymes cleave polysaccharides from microfibrils
104
Components of the cell wall
- cross linking polysaccharides
- cellulose microfibrils
- cell wall loosening enzymes
- expansions
105
leaf abscission
process of leaves changing color in fall due to respond to changes in light and temperature.
106
why does leaf abscission occur (3)
- chlorophyll production stops
-nutrience pulled from leaf -> roots and stems to store for winter
-abscission zone cells divide BUT stop elongating
107
abscission zone
where leaf falls off of tree; elongation stops -> tiny cells -> cell walls break down -> leaves fall off
108
chlorophyll pathway
stimulated by light -> vibrations -> mechanical energy -> chemical energy; reason why leaves are green
109
cartenoids
yellow and orange pigments that aid in light absorption during photosynthesis; present all year round
110
Anthocyanins
red pigment in leaves produced after abscission layer forms
*first yellow or orange -> some can change to red
111
how are Anthocyanins impacted by photosynthesis
Anthocyanins product of photosynthesis; more photosynthesis plant does -> redder leaves
112
Anthocyanins vs Carotenoids pigment year to year
Carotenoids: consistent color year to year
Anthocyanins: dependent on photosynthesis
*more moisture and sun -> redder leaves
113
leaf function
absorption of light and CO2 for photosynthesis
114
Types of mesophyll cells; ground tissue in leaf
palisade (closer to top) and spongy (closer to bottom)
115
cells that control stomas in the epidermis
guard cells (dermal cells)
116
what mesophyll cells do more photosynthesis
palisade mesophyll; more chloroplast and less air
117
where are the stoma in the leaf
lower epidermis (my spongy mesophyll)
118
function of spongy mesophyll
**allows airspace for CO2 to diffuse into the leaf
**backscatter to limit loss of photons
*also does some photosynthesis
119
what wavelengths of light have fastest rate of photosynthesis
purple, blue and red
120
air water interface
when light hits where air and water meet and some gets reflected back; backscatter
121
backscatter and the spongy mesophyll
lots of air water interfaces -> lots of backscatter -> photos back to palisade mesophyll for increased absorption
122
effect on photosynthesis when a leaf is upside down
lower synthetic rate because light enters spongy mesophyll first-> increased backscatter -> reflection of light out of the leaf
123
plant growth under experimental conditions light+water, only light and only water
light+water: grows and undergoes photosynthesis
only light: does not change in mass
only water (dark): cannot make more energy so undergoes respiration -> loses mass
124
calvin cycle
converts CO2 gas into sugars and low energy molecules for light reaction reactants
125
enzyme for calvin cycle
RuBisCo: initiated by binding Co2 to RuBP
*C3 photosynthesis
126
what multiple ways can RuBisCo react?
Calvin Cycle: Co2 -> sugars
Photorespiration: O2 -> CO2
127
when does RuBisCo undergo photorespiration
under high stress environments;
*stomata close to control water loss and CO2 concentration around RubisCO decreases -> takes in O2 more often
128
why did RuBisCO evolve to react with both O2 and CO2 even though O2 (photorespiration) is less favorable
at the time it evolved the atmosphere was mostly CO2 so no selective pressure for CO2 over O2
129
C4 photosynthesis
concentrates CO2 around RubisCO enzyme
*Kenz anatomy
130
when did C4 photosynthesis increase
when CO2 conc in the atmosphere decreased over time
131
krans anatomy
chloroplast concentrated in the bundle sheath cells (green ring around vascular tissues) / only in RuBisCO in BS cells (CO2 conc around it)
132
how does C4 photosynthesis pathway differ from C3
* 2 fixations of CO2
* 2 processes physically separated
*eliminates possibility for photorespiration
133
C4: first carbon fixation
PEP-C -> 4 carbon organic acid in mesophyll cell
134
C4 second carbon fixation
RuBisCO -> C sugar through calvin cycle in bundle sheath cells
135
where are the chloroplast conc in C3 vs C4 photosynthesis
C3: mesophyll cells
C4: cundle sheath cells
136
what is the cost of photorespiration
3 mol O2 -> 1 mol CO2 released; 2 mol ATP and 2 mol other high energy molecules used up
137
under what environmental conditions is C3 photosynthesis favored
Less stressful (cooler, less intense sunlight
138
under what environmental conditions is C4 photosynthesis favored
stressful conditions (hot, intense sunlight, hard to retain moisture)
139
pros of C4 photosynthesis
high photosynthetic capacity (high yield, fast growth) and high water use efficiency
140
cons of c4 photosynthesis
CO2 pump costs energy (ATP)
141
how does CAM photosynthesis differ from C3 and C4
*CO2 is taken in and stored at night (C4 cycle) and used to make energy during the day (calvin cycle)
* happens in the same cells but at different times
142
what types of plants do CAM photosynthesis
-plants in dry environments (CAM reduces water loss): cacti, desert plants, orchid, spanish moss, plants without roots that grow off other plants/ trees
-aquatic plants in lakes with very low CO2 conc; RuBisCO grabs CO2 during the day and PEP-C grabs CO2 at night.
143
suberization/ subrin
a process that occurs in plants after leaf abscission, when suberized cells form a sealing tissue
