Midterm 1 Flashcards
(292 cards)
1
Q
What are the fundamentals properties of life in plants?
A
- The organization of structure and composition (cells)
- Ability to grow and develop
- Its ability to reproduce (needs to be matured)
- Ability to respond to environments (adaptations like defense mechanisms)
- Ability to undergo metabolic processes like photosynthesis
- Ability to evolve and adapt (change over time)
2
Q
What do all land plants share?
A
Alternation between generations
3
Q
What is different between the prokaryotic kingdom and eukaryotic one?
A
Prokaryotes lack a nucleus and membrane covered organelles, while eukaryotes have this feature. In addition ALL prokaryotes are single celled while eukaryotes are a mix.
4
Q
How many divisions are there in the Kingdom Plantae?
A
12
5
Q
What are the organ systems of a plant?
A
The shoot and root organ systems
6
Q
What is a shoot organ system?
A
The plant’s components that are above the surface, including, the stem, leaves, and reproductive parts
7
Q
What is the root organ system?
A
The plant’s components that are below the surface consisting of the roots and its associated structures.
8
Q
What are the two types of roots?
A
Main and peripheral
9
Q
What is the purpose of root hair?
A
To increase surface area in order to allow for better uptake of nutrients and water.
10
Q
What are the 4 divisions of land plants?
A
- Bryophytes (non-vascular plant)
- Seedless vascular plants
- Seed-bearing plants (gymnosperms)
- Seed-bearing plants (angiosperms)
11
Q
What are the main types of bryophytes?
A
Moss
12
Q
Why are mosses low to the ground?
A
They lack a vascular system
13
Q
What is a vascular system?
A
Transportation of nutrients across organism
14
Q
What is the main type of seedless vascular plants?
A
Ferns
15
Q
What are the main type of seed-bearing vascular gymnosperm plants?
A
Conifer plants (produce cones)
16
Q
What are the main type of seed-bearing vascular angiosperm plants?
A
Fruit plants
17
Q
What do all the four divisions of land plants have in common?
A
Are embryophyte
18
Q
What is an embryophyte?
A
Embryo within the female reproductive structure
19
Q
What is the difference between gymnosperms and angiosperms?
A
Gymnosperms are naked seeds, thus no protective coating while angiosperms have a protective covering (fruit).
20
Q
How do aquatic plants differ from land ones?
A
Don’t have an embryophyte
ex. green algae
21
Q
Explain alternation of generations
A
Life cycle of alternating diploid sporophyte phase and haploid gametophyte phase
22
Q
What is the difference between a sporophyte and gametophyte?
A
Sporophytes produce spores and exist as 2n while gametophytes produce gametes and exist as n.
23
Q
What do sporophytes produce?
A
Sporangeium
24
Q
What occurs in a sporangeium?
A
Meiosis
25
What is a female gametophyte in a bryophyte?
An archegonium (where the egg is)
26
What is a male gametophyte in a bryophyte?
An antheridium (where the sperm is)
27
What do bryophytes do to gain nutrients?
As mosses don't have a vascular system, there are low lying where they absorb any nutrients that are close to the ground.
28
What moss to the touch, is its gametophyte form?
Spongy moss
29
What part of the moss is its sporophyte part?
The capsule at the top (meiosis takes place to release spores here)
30
Do the spores of bryophytes have to form a specific gametophyte?
Nope, either form a male or female
31
Heterosporous
Produces two kinds of spores
32
Homosporous
Produce one kind of spore
33
What type of spore can bryophytes be?
Either hetero or homosporous
34
Why must bryophytes be drought tolerant?
They don't have a vascular system that can move their nutrients everywhere, so most of their life cycle occurs in dry environments
35
What anchors bryophytes?
Rhizoids (their "roots")
36
Where are spores produced in mosses?
Gametophyte capsules
37
What is the importance of mosses?
Enable other plants to grow as they keep conditions around moist and maintain moist soil (are the first plants to grow; rocks).
38
What transports water in fern?
Xylem
39
What transports sugar and other material in ferns?
Phloem
40
Fronds
Leaf-like part of ferns
41
Where do fronds come from?
A horizontal underground stem known as a rhizome
42
Rhizome
A horizontal underground stem that store starch and protein and allow them to grow underground
43
Where do roots arise from?
The rhizome system
44
Where does a sorus exist?
The underside of a frond (round)
45
What does a sorus do?
Spores form here
46
How do spores grow on a sorus?
Meiosis takes place once the spores take place in a sorus, mature, then are released from a circle thing
47
What are the gametophytes of ferns?
Prothallus
48
What happens if a gametophyte of a fern forms on the ground?
An archegonium and antheridium will form (moss ones)
49
How can gametophytes on the ground fertilize?
The sperm has flagella, so it moisture can allow it to travel to the archegonium
50
How does a mature sporophyte differ from a young one of a fern?
A mature sporophyte doesn't have a gametophyte attached while a young sporophyte in a fern has one attached
51
What types of spores do ferns produce?
Homosporous
52
Since a fern produces homosporous spores, how do their gametophytes look like?
Both female and male parts
53
Phytoremediation
Use of plants to remove toxic waste from the environment like pesticides, oils, etc. (work good when low)
54
What plants are used in phytoremediation?
Ferns
55
What areas do ferns grow in?
Moist areas, like the undergrowth of a forest
56
Where are the seeds from in conifers?
Inside the cones
57
How are the mature seeds released from the cones?
Must open up
58
What are the three types of conifers?
1. Pine
2. Cedar
3. Spruce
59
What do the cones look like in pine trees?
Open cones
60
How do cones exist in cedar trees?
In clusters with needles one on top of the other (scaling)
61
How do cones exist in spruce trees?
Less open than pine cones are are very delicate where if you pull a needle, a piece of bark will fall off too
62
In a pine tree's life cycle, what stage is more dominant?
Sporophyte cycle
63
Where does the haploid cycle exist in pine trees?
Inside the cone
64
What do female gametophytes in pine trees exist as?
Egg cells
65
What do male gametophytes in pine trees exist as?
Pollen
66
What are ovules in pine trees?
Where the egg forms when ovulation takes place
67
Mega spores
Female spores in pine trees
68
Micro spores
Male spores in pine trees
69
How many mega spores are produce in meiosis in pine trees?
4
70
What happens once the spores in pine trees mature?
Produce cones
71
What's difference in the position between female and male cones in pine trees?
Female cones are farther up the tree while male cones are farther down the tree
72
What happens once the sperm of the pollen grain gets inside the female cone?
It fertilizes the egg
73
How many megaspores produce egg cells? How many egg cells?
One of the four megaspores produce 2 egg cells
74
What type of spores do conifers produce?
Heterosporous spores
75
Where does a female gametophyte exist in a pine tree?
Inside the cone
76
Where does a male gametophyte exist in a pine tree?
Inside a pollen cone
77
Explain the sporophyte process in a pine tree.
Fertilization of a egg from a sperm of a pollen grain where the zygote forms an embryo within a female cone; cell division to lead to differentiation where it leads to a seedlings that forms into a tree
78
What is the usual form of a male gametophyte in an angiosperm?
Pollen
79
Where do sepals exist?
Below the petals on the outer parts of the flower
80
What is the purpose of the sepals?
Enclose the bud at the beginning of the season
81
What happens when the sepals open?
Out come the petals
82
What are the rings of stock on the centre of the flower?
Male stamen, male reproductive system
83
What are male stamen made up of?
The anther and filament
84
What is the purpose of the anther?
To release and make pollen grains
85
What do filaments do?
Keep the anthers up high
86
What is in the centre of angiosperms; the flower?
The carpel, female reproductive system
87
What does the female reproductive system (carpel) contain?
Stigma, style, and ovary
88
What is the purpose of the stigma?
Exists high up and has a sticky substance in which pollen can stick on
89
When a pollen grain attaches to a style, what happens?
Makes a pollen tube that slides down the style and enters the ovary
90
What is a well known angiosperm plant in Canada?
Trillium
91
What type of spores do angiosperms release?
Heterosporous
92
What are two types of angiosperms?
Monocots and dicots
93
Explain monocot root systems.
Fibrous, which are thin, moderately branching roots from the stem
94
Explain dicot root systems.
Taproot, where there is a single, thick main root with several lateral branches
95
What is a cotyledon?
The first leaf-life structures produced when developing
96
How do monocot leaves look like?
Parallel vein leaves
97
How do dicot leaves look like?
Net-like veins on leaves
98
How do petals exist on monocots?
Multiples of threes (lilly, trillium, etc.)
99
How do petals exist on dicots?
Multiples of four or five
100
How do ovules exist in monocots?
Multiples of three ovules in the ovary
101
How do ovules exist in dicots?
One ovule in the ovary
102
What are paleodicots (basal angiosperms)?
Those plants with primitive characteristics that evolved before the divergence of monocots and eudicots
103
What is the difference between a monocot and dicot?
A monocot has one cotyledon and a dicot has two (seed leafs)
104
What are eudicots?
Also known as true dicots (the same thing)
105
Who is the father of taxonomy?
Linnaeus
106
How are plants grouped together?
Evolutionary relationships because of shared morphology and anatomy
107
How were plants originally classified?
Using human sexuality such as marriages and the number of beds
108
What were the problems associated with Linnaeus' naming systems?
Hard to identify a hybrid and the naming all depends on which characteristic you choose (many)
109
What is a binomial name?
A two part name with the genus (broad) and species (specific to one)
110
Order the domains in the classification of plants (Linnaeus system).
From broad to narrow:
Kingdom --> Division --> Class --> Order --> Family --> Genus --> Species
111
What is the Linnaeus system based on?
Similarities in observable physical traits
112
Why don't we use common names for plants?
Names can differ from location
113
What is a clade?
A group of organisms with similar traits that are believed to come from a shared recent common ancestor.
114
Monophyletic
Clades on a phylogenetic tree where a group of organisms originate from a shared common ancestor, so they display similar traits.
115
Why are some common and genus names helpful?
Some names describes the physical qualities, use, or location, so that they are easily distinguishable.
116
How to recognize a family name?
All end in -aceae.
117
What is phylocode?
A tree of life designed by reference to phylogeny by using a formal set of rules that govern phylogenetic nomenclature.
118
What is the classification in the phylocode based on?
Clades
119
What is the barcode of life?
A tool for species identification by sequencing a standard region of DNA.
120
What DNA regions are used for a barcode of life?
Short, highly variable regions of the genome
121
What is the tool used in DNA barcoding?
PCR, so that DNA can be amplified
122
What specimens can be used for PCR?
Small or degraded specimens
123
What 2 genes were used for species identification for DNA barcoding?
1. rbcL
2. matK
124
What is the rbcL gene used for?
A chloroplast gene that codes for a Rubisco large subunit.
125
What is the matK gene used for?
A gene that codes for maturase K protein, which splices introns.
126
What gene is used for DNA barcoding in animals?
CO1 gene
127
Why isn't the CO1 gene used in barcoding for plants?
This gene evolves slowly in plants, so it doesn't allow for much differentiation between species.
128
Biological species concept
A species is a group of interbreeding populations that are reproductively isolated from other groups, producing viable offspring.
129
Ecological species concept
A species is a member of a biological community defined by a set of unique of adaptations to its environment.
130
Genealogical species concept
A species is a group of organisms with a distinct genetic history (organism more closely related to others in a group than those on the outside).
131
What does natural selection rely on?
1. Variation
2. Overpopulation
3. Competition
4. Individuals with beneficial traits that will have the greatest reproductive success
132
Can an organism change its trait?
No it can't change its trait as it's inherited, just not pass it on as it's not beneficial
133
How does artificial selection relate to natural selection?
Humans select for the beneficial trait rather than the environment
134
What are the levels of organization in plants?
High to Low:
organism --> organ system --> organ --> tissue system/group --> tissue --> cell
135
What is an organ made of?
2 or more different kinds of tissues that are each separately made of similar cells
136
What are the organs in a plant?
Root, stem, reproductive structures, and leaf
137
What tissue make up a root?
Dermal tissue, ground tissue, and vascular tissue.
138
What is a blade?
The flat, extended part of a leaf.
139
What is a petiole?
The stalk that attaches the blade to the stem.
140
What makes up a leaf?
Blade and petiole
141
What is an axillary bud?
New bud for anything like a stem, leaf, fruit, etc.
142
What are stipules?
Little thorns
143
What are leaflets?
Those not borne on the main stem, so three leaflets equal 1 whole leaf.
144
What are the types of composition for leaves?
1. Simple
2. Palmately compound
3. Pinnately compound
145
What is a simple composition for a leaf?
A single blade, petiole, axillary bud, and stipules.
146
Do all leaves have petioles?
No, as some are directly attached to the stem
147
What is a palmately compound composition for a leaf?
Leaflets originate from the center, similar to a palm (near end of petiole)
148
What is a pinnately compound composition for a leaf?
Alternating leaflets originating from different locations on a terminal petiole (not the center; along the entire petiole).
149
What are the arrangements of leaves?
1. Alternate
2. Opposite
3. Whorled
150
What are the alternate arrangement of leaves?
Alternating nodes on opposite sides of a stem or petiole
151
Nodes
Area where a bud grows into a leaf
152
Internode
Distance between nodes
153
What is the opposite arrangement of leaves?
The nodes are located on opposite sides but at at the exact same position
154
What is the whorled arrangement of leaves?
There are multiple nodes at one location on the same side, can differ sides as well.
155
What are the types of veins on leaves?
1. Parallel
2. Net-like
156
What are the different types of carpel?
1 carpel vs fused carpel
157
What is one carpel?
Only 1 ovule arose from the ovary
ex. pit in cherry
158
What is the fused carpel?
Multiple ovulves are in the ovary
ex. each section in a lemon
159
What is the symmetry like in a regular flower?
Radial symmetry
160
Radial symmetry
Multiple planes
161
What is the symmetry like in an irregular flower?
Bilateral symmetry
162
Bilateral symmetry
One plane
163
Superior ovary
The stamen is underneath the ovary
164
Inferior ovary
The stamen in on top of the ovary (attached at the top)
165
What is the purpose of the potato experiment?
Demonstrates the tonicity (water movement) of plant cells as those in the salt water turn floppy (water moves out of cell) and tap water (water comes in to make it firm)
166
What are the three tissue systems in plants?
1. Dermal
2. Ground
3. Vascular
167
What makes up the dermal tissue?
Epidermis and periderm
168
What is the purpose of the epidermis?
The protective outside covering of plants that prevents water from evaporating due to its cells being tightly packed.
169
What makes up the ground tissue?
Parenchyma, collenchyma, and sclerenchyma.
170
What makes up the parenchyma?
Mesophyll cells and the cortex
171
What do mesophyll cells do ?
Contain chloroplasts that help with photosynthesis.
172
Where are most mesophyll tissue located?
In leaves due to its green colour (photosynthesis).
173
What does the cortex and pith cells do in the stem (ground tissue)?
Support and storage
174
What is the difference in the location between the cortex and pith?
The cortex is located between the vascular tissue along the outside while the pith in inside the vascular tissue.
175
What makes up the periderm?
Cork cells
176
What is located in the lower epidermis?
The stoma
177
What does the stoma do?
Good for water release and CO2 uptake.
178
What surrounds the stoma? Purpose?
Guard cells on each side which control the size of the stoma (open and closing).
179
What does the endodermis do (ground tissue)? Location?
Located in roots and helps to anchor plants/allow for sturdiness.
180
What vascular tissue makes up a vein?
Xylem and phloem.
181
What makes up xylem?
Tracheids and/or vessel elements, fibers, and parenchyma.
182
What makes up phloem?
Sieve tube members AND companion cells, fibers, and parenchyma.
183
What is the makeup of a parenchyma tissue?
Primary cell wall, which is thin and a pit.
184
What are pits and their function?
There are tiny holes in the cell wall that allow for communication between neighbouring cells.
185
What is the makeup of a collenchyma cell?
Primary cell wall, thick, and a pit.
186
How do cells in the parenchyma appear (shape)?
Circles
187
How do cells in the collenchyma appear (shape)?
Long and more tubular.
188
What is the purpose of collenchyma cells?
Make up the growing parts of plants, so provide flexibility and sturdiness (thick primary cell wall).
189
What makes up a sclerenchyma tissue?
Fiber and sclereid cells.
190
What is the purpose of sclerenchyma tissue?
Provide support and mechanical protection due to secondary cell wall (inflexible).
191
What makes up a fiber cell?
Pits, secondary and primary cell wall, and lignin.
192
What is the shape of a fiber cell?
Elongated, stringy tubes.
193
What is the make up of a sclereid cell?
Primary and secondary cell wall, pits, and lignin.
194
What is the shape of sclereid cells?
Circular.
195
What happens to the tracheids and vessel elements when they mature?
After maturity, they die and hollow out, thus allowing water to flow easily.
196
What is the makeup of tracheids?
Long, thin cells with tapering and pointed ends. Many pits are throughout them.
197
What is the makeup of vessel elements?
Wider and shorter cells that stack up on one another. Pits throughout as well.
198
What is the advantage of vessel elements? Disadvantage?
More water flows because of the wide diameter; however, if one is blocked, water can't flow as they are all stacked one on top of the other.
199
What is the makeup of a sieve tube member?
Multiple tubular cells with a sieve plate between that contains large pores.
200
What is the purpose of sieve tub members/plates?
Nutrients travel here
201
What does the companion cell? do
Attached to sieve tube member and allows materials from other cells to enter the sieve and leaves it to enter other cells.
202
What is the purpose of a central vacuole?
Waste collection and water/pigment storage.
203
What makes up the primary cell wall?
Cellulose
204
What makes up the secondary cell wall?
Lignin
205
What connects two neighboring cells and their primary cell walls?
Middle lamella (a sticky substance).
206
What is the purpose of plasmodesmata?
Connects neighbouring cytoplasm so that passageways can occur (movement of materials).
207
How does the layers of the phospholipid bilayer compare?
A fluid mosaic model where both sides consist of different integral and peripheral proteins.
208
Do all materials pass through the phospholipid bilayer?
No, it's semi/selectively/differentially permeable, so ONLY some things can pass through whereas others don't.
209
Tonicity
Water movement (high to low areas)
210
Isotonic
Same water concentration on both sides of the cell, so there is an equal amount moving in and out.
211
Hypotonic
There is a greater water concentration outside of the cell, so therefore water moves into it (more).
212
Hypertonic
There is a greater water concentration inside of the cell, so therefore lots of water leaves he cell than water that enters.
213
Will plants cells burst in hypotonic conditions?
No, because the cell wall is rigid there is just more pressure.
214
What is a hypotonic plant cell called?
Turgid cell because it's tough and deals with a lot of pressure.
215
What happens when a plant cell goes through hypertonic conditions?
Can become plasmolyzed (shrinks) where the cell membrane separates from the cell wall, thus resulting in death.
216
What are the three important physiological processes for plant life?
1. Transport of water into and through a plant; and of sugars through a plant
2. Photosynthesis
3. Cellular respiration
217
What are the three substances required by plants?
CO2, O2, and water
218
Photosynthesis
The use of carbon and water with the addition of light to create glucose (food) and oxygen
219
Cellular respiration
The use of glucose and oxygen to make carbon dioxide, water, and ATP (energy)
220
How does water enter a plant?
Water and its dissolved minerals enter through the roots.
221
How does oxygen enter a plant?
Through the roots
222
How does carbon dioxide enter a plant?
Through the leaves
223
How does sugar leave a plant?
Either through roots or leaves
224
How does sugar enter a plant?
Leaves
225
How does oxygen leave a plant?
Leaves
226
How does carbon dioxide leave a plant?
Through the roots
227
How does water leave the plant?
Stays in leaves where it can be absorbed by the sun (dried out).
228
Transpiration
A process that involves the loss of water through the stomata of plants.
229
How does water reach the xylem?
H20 is absorbed by the roots through dermal tissue and then ground tissue until it gets to the vascular tissue cylinder.
230
What does water have to go against as it moves up the stem in the xylem?
Gravity, as it moves up.
231
What is the endodermis?
Inner layer of the cortex
232
Explain the structure of the endodermis.
One layer of tightly packed cells with a waxy suberin that lines the cells on 4 sides.
233
What can pass through the waxy suberin/Casparian strip?
Nothing can pass through it, specifically water
234
How can water pass through the endodermis?
Avoids the Casparian strip and passes through the endodermal cell (selectively permeable).
235
What are the routes water takes to the xylem?
1. Apoplastic route
2. Symplastic route
236
Apoplastic route
The route of water from the roots to the xylem consisting of moving on the outside of the cytoplasm either within cell walls and intercellular spaces.
237
Symplastic route
The route of water from the roots to the xylem consisting within the cytoplasm of the cortex through plasmodesmata.
238
How do guard cells open the stomata?
Lots of water enter the guard cells causing them to bend in the center, thus increasing the diameter of the stoma and more water can diffuse out.
239
What are guard cells called when water enters them?
Turgid
240
How do guard cells close the stomata?
Less water, so they leave the guard cells causing them to move closer together (centers), thus decreasing the diameter of water and reducing the amount of water that leaves the plant.
241
What are guard cells called when water leaves them?
Flaccid
242
What is the transpiration-cohesion theory?
Transpiration increases tension of neighbouring water molecules, pulling the rest up, but it's due to its cohesive ability that this can occur.
243
Explain cohesion in water molecules.
It's ability for it to form bonds with other water molecules through hydrogen bonding thus forming long columns in the xylem.
244
Explain adhesion in water molecules.
It's ability to form bonds with non-water molecules, like the cell walls in xylem.
245
What is the importance of adhesion?
Prevents the whole chain from falling back down.
246
How does water flow through tracheids?
Water flows vertically and laterally through pits (end of each cell).
247
How does water flow through the vessel elements?
Short, vertical water flow through the perforated and open ends.
248
How does water flow through the pits of vessel elements?
Laterally
249
How does sugar flow through an angiosperm?
From the source to the sink.
250
Source
The location that supplies sugar molecules for transport or release them for their storage supply.
251
Sink
The location of low concentration of sugar that needs it for metabolic processes.
252
How do sieve tube members differ from the components of xylem?
There are alive and move nutrients rather than water.
253
How does sugar get out of the source into sieve tube members?
Through active transport by the plasmodesmata.
254
How does sugar get out of the sieve tube member to the sink?
Through active transport by the plasmodesmata.
255
What is the pressure flow hypothesis?
Sugar concentrations in the sieve tube members cause water from the xylem to move into the member as well, thus an increase in pressure and mass flow of both molecules to lower concentrations.
256
What happens to water in the sieve tube members when sugar reaches the sink?
The sugar concentration decreases in the last sieve tube member where it causes the water to move out of the member into nearby cells or xylem.
257
Active transport
Molecules move from lower concentration to higher concentrations by a gradient or protein that expends energy.
258
What is the difference between the vascular cylinder in dicot and monocot roots?
Dicot roots have a cross section of xylem while the monocot root has the xylem arranged in circular bundles
259
What does a monocot root have that a dicot root doesn't?
A pith
260
What does the endodermis surround?
The vascular cylinder
261
What does dicot stem have that a monocot stem doesn't?
A pith
262
How are vascular bundles arranged in a monocot stem?
In bundles scattered throughout
263
How are vascular bundles arranged in a dicot stem?
Surround the stem in a circle near the outside
264
What exists between phloem and xylem in a dicot stem?
Vascular cambium
265
Where does xylem exist in reference to the phloem?
Towards the center (inside of the phloem)
266
Where does the phloem exist in reference to the xyelm?
Towards the outside of the cell (above xylem)
267
How does the xylem and phloem exist in a dicot leaf?
Branching to give net-like veins (a central vein)
268
How does the xylem and phloem exist in a monocot leaf?
A parallel vein formed by the vascular bundles existing in a coordinated line
269
Where does primary growth occur?
In the apical meristem, specifically dermal, ground, and vascular tissue (specifically primary xylem and phloem)
270
Where does secondary growth occur?
In the lateral meristem, the cork and vascular cambium (specifically secondary xylem and phloem).
271
What is primary growth?
Growing upwards in height or downwards by deepening roots.
272
What is secondary growth?
Wider in circumference (girth)
273
What occurs in a meristem?
Active cell division
274
Where are apical meristems located?
At the tip, so terminal buds or in root tips.
275
Why doesn't the apical meristem exist at the very end of the root?
Since the soil is abrasive, it would wear away the delicate, dividing cells, thus damaging any growth.
276
What protects the apical meristem in roots?
A root cap
277
List the structures that grow in primary stage (in order of each stage).
Procambium --> protoderm and ground meristem --> epidermis, cortex, pith, primary xylem and phloem
278
What later stage of growth occurs in a dicot plant?
Procambium develops into vascular cambium, which turns into secondary xylem and phloem.
279
What are the three zones growth in a root?
1. Zone of cell division
2. Zone of cell elongation
3. Zone of maturation
(young to old)
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Zone of cell divsion
Cells are dividing where a majority occurs in the apical meristem
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Zone of cell elongation
Cells are elongating, so roots deepen and stems grow in height
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Zone of maturation
No more cell elongation or division, so new structures like root hairs can develop
283
Why doesn't secondary growth occur in monocots?
They ONLY live in one season and die off as they don't have vascular cambium
284
What are examples of dicots?
Trees and woody plants as they have secondary growth (survive throughout each season)
285
What growth occurs in dicots during late summer (1st year - secondary)?
1. Vascular cambium divided in secondary xylem and phloem
2. Secondary xylem becomes wood (moving towards the center)
3. Secondary phloem converts itself into cork cambium --> becomes cork
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Cork cambium
Single layer of actively dividing cells (alive) that produce cork
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Why is bark tough?
Constantly eroding due to any environments or other conditions
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What happens in the secondary growth in the second year of later summer?
1. New layers of secondary xylem (alternating from large cells to small cells)
2. More phloem converted into cork cambium (about the same size still); however, more layers of cork
289
What makes up bark?
Secondary phloem, cork cambium, and cork.
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Why are there alternating layers of large and small cells in the secondary xylem?
During early summer, there are lots of water so vessel elements are large to combat the transport of water; however, as the end of summer nears, there is less water, so these elements hollow out, die and shrink (not needed as much).
291
What are wood rings?
Secondary xylem, specifically the small vessel elements as they are tiny and squashed together to make a compact line.
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What structures lengthen in primary growth?
Terminal buds either though increasing stem length or a flower; axillary buds through branching, leaves, or flowers; and root tips by deepening in the soil.
