Plants Flashcards
1
Q
What are the 6 characteristics of land plants?
A
1) Eukaryotic, multicellular (nucleus)
2) Autotrophs = produces own food using light
3) Cell wall (cellulose, sporopollenin)
4) Embryophytes = plants with protected embryos
5) Terrestrial
6) Alternation of generations
2
Q
what is sporopollenin?
A
in seed coat, very durable polymer
3
Q
What is the alternation of generations?
A
the gametophyte (multicellular) is haploid and produces haploid gametes by mitosis, fusion of gametes gives rise to diploid sporophyte (multicellular) which produces spores by meiosis
4
Q
What types of plants have alternation of generations?
A
All plants
5
Q
What is the trend with the gametophyte of plants throughout evolution?
A
There is a trend toward reduction of the gametophyte generation in plant evolution
6
Q
How long ago was the origin of plants?
A
~470mya
7
Q
When was the origin of vascular plants?
A
~425mya
8
Q
When was the origin of seed plants?
A
~360mya
9
Q
What are the closest relatives of land plants?
A
green algae called charophytes
10
Q
What’s limited in water for plants?
A
light is less available
11
Q
What’s limited on land for plants?
A
harder to get access to water
12
Q
what are the 3 things plants need when on land?
A
1) water transport mechanisms = vascular tissue (veins)
2) physical support
3) mechanism to distribute gametes and progeny
13
Q
what are the 4 adaptations of land plants developed to thrive on land?
A
1) cuticle: wax coating that prevents water loss
2) Stomata: openings in stems and leaves; regulate gas exchange
3) vascular tissue: conductive tissue that allows for the movement of water and sugar (xylem and phloem)
4) embryo in a protective structure (seeds instead of spore)
14
Q
what are 3 groups of plants in bryophytes or nonvascular plants?
A
1) Mosses
2) liverworts
3) hornworts
15
Q
what are 2 general characteristics of non-vascular plants?
A
tiny, and can be found in the shade in moist environments because they don’t have vascular tissue
16
Q
Why couldn’t bryophytes grow as tall as trees?
A
no vascular tissue
17
Q
How does water transport occur in non-vascular?
A
via diffusion
18
Q
What 4 structures do non-vascular plants lack?
A
1) They have a thin cuticle or no cuticle, and most live in moist habitats
2) lack true leaves
3) lack stems
4) lack roots
(but have analogous structures)
19
Q
What is the phylum of liverworts?
A
Hepatophyta
20
Q
What’s the phylum for mosses?
A
Bryophyta
21
Q
What’s the phylum of hornworts?
A
Anthocerophyta
22
Q
What’s the trend for gametophytes and sporophytes in non-vascular plants?
A
Gametophytes are larger and longer-living than sporophytes: gametophyte generation is visible and the sporophytes are very small and can only be seen at certain times AND Sporophyte relies on the gametophytes for nutrients
23
Q
What are the 2 erect structures in liverworts that contain the multicellular gametangia?
A
Archegoniophore and antheridiophore
24
Q
Where are eggs and flagellated sperm produced in liverworts?
A
Mature gametophytes produce flagellated sperm in antheridia and an egg in each archegonia
25
What 3 structures do all nonvascular plants sporophytes have?
1) Foot: absorbs nutrients from the gametophyte
2) Seta: or stalk transfer nutrients to the sporangium/capsule
3) Capsule/sporangium: uses nutrients to produce spores
26
What structure is unique to liverwort sporophytes?
Elaters (blue threads) = cells which aid in the dispersal of spores (red dots)
27
How do liverworts reproduce asexually?
by fragmentation of the gametophyte: Gemmae = clumps of cells in gemmae cups. Gemmae are dispersed by splashes of water in the cups (raindrops)
28
What are Gemmae?
small, multicellular, asexual reproductive structures that help in vegetative propagation. They are produced in specialized cup-like structures called gemma cups (gemmae cups), which are found on the surface of the liverwort thallus.
29
How are gemmae dispersed?
by water
30
Which liverwort are gemmae common in?
Common in Marchantia
31
How do gemmae develop?
Gemmae are haploid and develop mitotically from the gametophyte
32
Why are liverworts thought to be the first nonvascular plant on land?
Liverworts thought to be the first on land because they do not have stomata; still have pores, but cannot open and closed based on external conditions (air on the epidermis of thallus) -> no guard cells
33
How are eggs and sperms produced in mosses?
Mature gametophytes produce flagellated sperm in antheridia and an egg in each archegonium. Sperm swim through film of water to reach fertilized egg
34
through what structure do sporangium in mosses discharge spores?
sporangium (capsule) discharges spores through a peristome
35
What is the young gametophyte of mosses called?
protonema
36
What do protonema resemble?
resembles filamentous green algae
37
When do spores disperse in mosses?
spores disperse when the capsule (sporangium) dries, the peristome opens and the operculum pops
38
What part of the peristome responds to humidity and what occurs when it's dry?
Peristome teeth respond to humidity, bending outward and opening the sporangium when the air is dry
39
What do hornworts lack that both liverworts and mosses have?
lacks a stalk
40
what are the gametophytes of hornworts?
flat plates of cells
41
what do sporophytes of hornworts look like?
look like small horns
42
How many chloroplasts do hornwort cells have?
Hornworts cells have a single, large chloroplast
43
what are the 2 clades in seedless vascular plants?
Lycophytes and Monilophytes
44
Ferns and other seedless vascular plants were the first plants to grow tall, how?
vascular tissue
45
What allowed seedless vascular plants to spread to new environments and diversify?
the ability to transport water and food throughout their bodies through their veins
46
where do seedless vascular plants typically live?
Seedless vascular plants have flagellated sperm and are usually restricted to moist environments
47
out of the 2 clades within seedless vascular plants, which is hypothesized to show up first?
Lycophyta: hypothesized to have shown up on land first because they have microphylls
48
What 3 groups of plants are found within monilophyt?a
ferns, horsetails, whisk ferns
49
what's the trend of gametophytes and sporophytes in seedless vascular plants?
Sporophyte is larger than the gametophyte now
50
What's the name of gametophytes in monilophytes?
Prothallium
51
what does the gametophyte of monilophytes look like?
heart shaped, male and female are together -> top portion = female or archegonium and bottom = male or antheridium
52
instead of roots, what do monilophytes have?
rhizoids
53
What is the function of rhizoids?
anchors organism on the substrate
54
out of all the groupings of plants: bryophytes, monilophytes and lycophytes, gymnosperms, and angiosperms, which have sporophytes that are completely independent of the gametophyte?
sporophytes of seedless vascular plants are independent of the gametophyte and are no longer dependent on it for nutrients
55
Where do the gametophytes of monilophytes reside?
Gametophytes are tiny plants that grow on or below the soil surface
56
Are ferns homosporous or heterosporous?
homosporous: produce 1 type of spore
57
what are sporangia?
are born on a stalk in clusters called sori on the underside of the fern leaf
58
What are sporophylls of ferns?
modified leaves with sporangium
59
what are strobili?
Lycophytes and horsetails produce spores in a cone-like structure called a strobilus
60
what are sori?
a cluster of spore-producing receptacles on the underside of a fern frond
61
What are 2 general characteristics of all seedless vascular plants?
1) All seedless vascular plants have conducting tissues with lignin (can grow bigger and upward)
2) The gametophyte is physically independent of the sporophyte, but the sporophyte is larger and longer-lived
62
What are 2 key adaptations that are observed in gymnosperms and angiosperms?
seeds and pollen grains are key adaptations for life on land
63
What was the downside of the evolution of embryo retention?
in ferns and horsetails, sporophytes have to live in the same place as their parent gametophyte, while seed plants overcome this limitation = embryos of seed plants are portable and can disperse to new locations
64
What are 3 evolutionary advantages that sees provide over spores?
1) remain dormant until conditions are favourable for germination
2) seeds have a supply of stored food
3) they may be transported via wind or animals
65
True or false: the most ancient vascular plants were heterosporous?
FALSE: homosporous
66
What are the 2 types of spores produced by heterosporous plants?
1) Megaspores: develop in female gametophytes - megagametophytes, which produce only eggs
2) Microspores: develop into male gametophytes - microgametophytes which produce only sperm
67
what are 3 components that ovules consist of?
1) megasporangium
2) megaspore
3) one or more protective integuments
68
How many integuments do the megaspores of gymnosperms and angiosperms have?
Gymnosperms = 1 integument
Angiosperms = usually 2 integuments
69
What do microspores develop into and what do they contain?
pollen grains, which contain male gametophytes
70
What is pollination?
the transfer of pollen to part of a seed plan containing ovules
71
what does pollen eliminate the need for?
eliminates the need for a film of water and can be dispersed by air or animals
72
If a pollen grain germinates, what does it give rise to?
If a pollen grain germinates, it gives rise to a pollen tube that discharges sperm into female gametophyte within ovule
73
What does the megaspore within an ovule of a gymnosperm develop into?
A megaspore develops into a female gametophyte, which produces an egg
74
What develops from the whole ovule?
A seed
75
What is a seed?
a sporophyte embryo
76
true or false: gymnosperms bear "naked" seeds typically on cones?
TRUE
77
what are seeds of gymnosperms exposed on?
The seeds are exposed on sporophylls that form cones
78
what are most gymnosperms?
Most gymnosperms are cone-bearing plants called conifers
79
What are 3 key features of gymnosperms life cycle?
1) dominance of sporophyte generation
2) development of seeds from fertilized ovules
3) the transfer of sperm to ovule by pollen
80
in the pine tree life cycle, what is the sporophyte and what does it produce?
The pine tree is the sporophyte and produces sporangia in male and female cones
81
what are the male cones of the pine tree like and what do they produce?
Small cones produce microspores that develop into pollen grains, each containing a male gametophyte
82
what are the female cones of the pine tree like and what do they produce?
The familiar larger cones contain ovules, which produce megaspores that develop into female gametophytes
83
in the pine tree life cycle, how long does it take to go from cone production to mature seed?
3 years
84
In staminate cones, what are microsporophylls?
Microsporophylls are modified needles
85
in staminate cones, what is contained within each microsporophyll?
Contained within each is a sporangium
86
in staminate cones, what do sporangium contain and what occurs to make spores then pollen?
sporangium contain microsporocytes (2N) where each one will undergo meiosis to produce 4 haploid spores. Each spore will develop into a pollen grain.
87
What do ovulate cones produce?
produce megaspore
88
what are the 4 phyla of gymnosperms?
1) Cycadophyta (cycads)
2) Ginkgophyta (one living species: Ginkgo biloba)
3) Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia)
4) Coniferophyta (conifers, such as pine, fir, and redwood)
89
What are 4 characteristics of the Phylum Cycadophyta?
1) Still have flagellated sperm**
2) These thrived during Mesozoic, but relatively few species exist today
1) Individuals have large cones and palm like leaves
4) Cycad roots harbour symbiotic nitrogen-fixing cyanobacteria; Cycads are popular landscaping plants
90
what are 4 characteristics of phylum Ginkgophyta?
1) Single living species, Ginkgo biloba
2) flagellated sperm
3) high tolerance to air pollution and is popular ornamental tree in cities
4) Grow as vines, trees, or shrubs
91
what are 4 characteristics of Phylum Gnetophyta?
1) very diverse
2) comprises of 3 genera: Gnetum, Ephedra and Welwitschia
3) Species vary in appearance, and some are tropical whereas others live in deserts
4) Grow as vines, trees, or shrubs; have vessel elements in addition to tracheids
92
what are the 3 genera within the gnetophyta phylum?
1) Gnetum
2) Ephedra
3) Welwitschia
93
what are 4 characteristics of Phylum Conifer?
1) largest of the gymnosperm phyla
2) Most conifers are evergreens and can carry out photosynthesis year round
3) Needle-like leaves have small surface area
4) They dominate high-latitude and high-altitude forests
94
what are the sporophyte and gametophyte of vascular seed plants like?
reduced gametophyte (usually microscopic), dependent on surrounding sporophyte tissue for nutrition and dominant sporophyte
95
Are all vascular seed plants homosporous or heterosporous?
All seeds are heterosporous
96
what are the 2 reproductive adaptations of angiosperms?
1) flowers
2) fruits
97
what are the most widespread and diverse plants?
angiosperms
98
What's the single phylum of angiosperms?
Anthophyta
99
what are Synapomorphies?
a character or trait that is shared by two or more taxonomic groups and is derived through evolution from a common ancestral form
100
what are the 8 synapomorphies of angiosperms?
1) flowers
2) fruits
3) reduced gametophytes
4) germination of pollen on a stigma
5) ovules and seeds enclosed in a carpel
6) double fertilization
7) endosperm (3N -> nutritive tissue for the embryo)
8) xylem with vessel elements
101
what are the 5 floral organs?
1) sepals
2) petals
3) stamens
4) carpels
5) perianth
102
what do the sepals form?
form an outer protective whorls
103
What are petals for?
furnish a visual advertisement to pollinators
104
what are stamens?
male reproductive structures that produce pollen
105
What are carpels?
female reproductive structures that produce ovules (pistil)
106
what is the perianth?
non-reproductive part of the flower = calyx (sepal) and corolla (petal)
107
what's another word for sepal?
calyx
108
What's another word for petal?
corolla
109
Arabidopsis flowers contain 4 different organ types organized into 4 concentric rings called whorls: what are they?
Whorl 1 = 4 sepals
Whorl 2 = 4 petals
Whorl 3 = 6 stamens
Whorl 4 = 2 carpels (compound pistil)
110
What type of pistil do Arabidopsis have?
compound pistil with 2 carpels
111
What are complete flowers?
When the 4 concentric groups of floral organs are present: sepals, petals, stems, and carpels
112
what are incomplete flowers?
when one or more floral organs aren’t present
113
what are perfect flowers?
have both male and female organs
114
What are imperfect flowers?
have either male or female organs
115
what does monoecious mean?
“one-house”; male and female flowers occur on same plant
116
What does Dioecious mean?
“two-housed”; male and female flowers on different plants
117
true or false: all imperfect flowers are incomplete?
TRUE
118
are all incomplete flowers always imperfect flowers?
NO - imperfect flowers are always incomplete, but incomplete flowers may or may not be imperfect.
119
what is a superior ovary?
sepals, petals and stamens are attached below the ovary
120
what is an inferior ovary?
sepals, petals and stamens attached near the top of the ovary
121
what are the 4 things that the angiosperm life cycle includes?
1) gametophyte development
2) pollination
3) double fertilization
4) seed development
122
what occurs in male reproductive organs of angiosperms?
diploid cells (microsporocytes) undergo meiosis to form 4 haploid cells (microspore). Then, Each microspore undergoes mitosis to produce 2 cells: generative cell and tube cell.
123
What 2 things does a pollen grain consist of?
2-celled male gametophyte and a pollen wall
124
at the immature stage, what does the male gametophyte of angiosperms consist of?
2 different cells:
1) small generative cell enclosed in a...
2) larger tube cell
125
what does the generative cell produce?
Haploid generative cell produces 2 sperms via mitosis
126
what develops within the ovule of female gametophytes of angiosperms?
The embryo sac, or female gametophyte, develops within the ovule. Within an ovule, 2 integuments surround a megasporangium. Then, 1 cell in the megasporangium undergoes meiosis, producing 4 megaspores, only one of which survives.
127
what is the placenta of an angiosperm?
portion of carpel which ovule is attached to
128
How does the production of the egg in the female reproductive organs of a flowering plant occur?
1) megasporocyte inside ovule undergoes meiosis = 4 megaspores, only 1 survives
2) surviving megaspore divides by mitosis to form 8 haploid nuclei
3) the 8 haploid nuclei rearrange; cell walls form to yield 7 cells and the large central cell has 2 nuclei
129
how many nuclei does the embryo sac of angiosperms contain?
Embryo sac contains 8 haploid nuclei and 7 cells. The larger central cell contains 2 polar nuclei
130
when does selfing occur in angiosperms?
Self-fertilization (selfing) occurs when a sperm and an egg from the same individual combine to produce offspring
131
When does outcrossing occur in angiosperms?
Outcrossing: much more common, occurs when sperm and eggs from different individuals combine
132
what does outcrossing result from?
It results from cross-pollination - when pollen is carried from the anther of one individual to the stigma of another individual
133
what is the definition of fertilization?
the fusion of sperm and egg to form a diploid zygote
134
what event triggers a series of events that lead to fertilization?
A pollen grain lands on the stigma of a mature flower and initiates a series of events that lead to fertilization
135
in angiosperms, when does double fertilization occur?
occurs when the nuclei of the egg and one sperm unite to form the zygote, the other sperm nucleus fuses with the 2 polar nuclei forming a triploid (3n) cell
136
what does double fertilization prevent?
This double fertilization prevents the waste of the plant's resources by ensuring that the nutrient-rich endosperm only develops if the egg is fertilized.
137
what does fertilization trigger the development of?
a young, diploid sporophyte
138
when does endosperm development occur?
Usually precedes embryo development
139
what does endosperm in angiosperms store?
stores nutrients that can be used by the seedling
140
what is embryogenesis?
the process by which a single-celled zygote becomes a multicellular embryo
141
In flowering plants, where does embryogenesis take place?
inside the ovule as the seed matures
142
what does Embryogenesis produce?
produces a tiny, simplified plant
143
what does a fruit develop from?
mature ovary of a flower
144
what is the function of the fruit?
It protects the enclosed seeds and aids in seed dispersal by wind or animals
145
what does the ovary wall of the fruit do?
The ovary wall surrounds the developing seeds and becomes the pericarp
146
What is pericarp composed of?
composed of 3 layers = exocarp, mesocarp and endocarp
1) Exocarp: outmost layer
2) Mesocarp: between the exo and endo
3) Endocarp: surrounds seeds
147
what is the definition of a simple fruit?
a single flower with 1 carpel or fused carpels
148
what is the definition of a compound fruit?
fruit developing from more than 2 ovaries
149
what is the definition of an aggregate fruite?
Formed from a single flower with multiple separate carpels
150
what is the definition of a multiple fruit?
formed from many flowers with many carpels
151
what is the definition of an accessory fruit?
formed from other floral parts in addition to ovaries
152
What do all fruits contain?
Seed containing the embryo, surrounded by a fruit that comes from the wall of the ovary
153
what is fruit taxonomy based on?
based consistency of the pericarp (dry and hard or soft and fleshy) in addition to the type of pistil (simple or compound)
154
what are the 2 major clades in angiosperms?
1) monocots
2) eudicots
155
what are monocots?
narrow-leaved plants such as grasses, lilies, orchids, and palms
156
what are dicots?
broad-leaved plants such as soybeans, roses, sunflowers, and maples
157
what is the stalk of the leaf called?
petiole
158
what does the petiole join?
joins leaf to a node of the stem
159
what are the veins of most monocots?
most have parallel veins
160
what are the veins of most eudicots?
most have branching veins
161
what are the 3Fs which are unique features of the angiosperm life cycle?
1) flowers
2) fruits
3) double fertilization
162
what 3 things are used to classify angiosperms?
leaves, flowers and fruits
163
what is the definition of tissues?
a group of cells that perform a specialized function composed of one or more cell types
164
what are organs made of?
Consist of several types of tissues
165
what is the most familiar and easily observed structures?
organs
166
what does natural selection do to plants?
natural selection shapes plant forms to fit their function at all levels
167
what are the 2 environments that vascular plants evolved to inhabit?
1) Below ground: absorb water and minerals
2) Above ground: Absorb CO2 and light
168
what are the 3 basic organs of plants?
1) Roots: absorb water and minerals
2) Stems: support the plant
3) Leaves: capture CO2 and light
169
what are the 3 functions of roots?
1) anchor plant
2) absorb H2O and minerals
3) store carbs
170
what part of the root acts as the primary site for absorption?
Root tips are a primary site for absorption because root hairs increasing surface area
171
what do root hairs do?
grow by the thousands just behind the tip of each root. They increase the root’s surface area, thus greatly enhancing the absorption of water and minerals from the soil
172
what are Mycorrhizal associations and what does it enhance?
symbiosis with fungi to enhance mineral absorption
173
what are the 2 functions of stems?
1) raises and separates leaves for better sunlight exposure
2) elevates reproductive structures for pollen and fruit dispersal
174
what are the 4 components of stems?
1) nodes: where leaves attach to stem
2) internodes: stem segments between nodes
3) axillary bud: can grow into lateral branch
4) apical bud: located at shoot top driving primary growth
175
what are 2 examples of specialized functions of stems?
storage and asexual reproduction
176
what is the primary function of leaves?
main site for photosynthesis
177
what's the structure of leaves? (2 components)
1) Blade: flattened part of the leaf
2) Petiole: stalk attaching the leaf to the stem (absent in many monocots)
178
true or false: monocots have petioles?
FALSE
179
where is the axillary bud in compound leaves?
Compound leaves have their axillary bud at the base of the stem before it branches out to its many leaves
180
What can compound leaves reduce?
Compound leaves may reduce damage from wind and pathogens
181
what are 4 examples of specialized functions of leaves?
support, protection, storage, and reproduction
182
what is the function of dermal tissue?
provides protective cover for the entire body of the plant
183
what is the function of vascular tissue?
transports materials between the root and shoot systems, is also continuous through the plant, but arranged differently in each organ
184
what's the function of ground tissue?
storage, photosynthesis, and support; responsible for most of the plant’s metabolic functions, is located between the dermal tissue and the vascular tissue in each organ
185
what 5 components are included in dermal tissue (protective)?
1) cuticle: waxy coating to prevent water loss
2) epidermis: outer layer in nonwoody plants
3) periderm: replaces epidermis in woody plants
4) specialized cells: guard cells regulate opening of stomata
5) specialized cells: trichomes reduce water loss and deter insects
186
what does periderm do?
replaces epidermis in woody plants
187
what do trichomes do?
reduce water loss and deter insects
188
what 3 components are included in vascular tissue? (transport and support)
1) xylem
2) phloem
3) stele
189
what does xylem do?
moves water/minerals upward from roots to shoots
190
what does phloem do?
transports sugars from leaves to other parts
191
what does stele mean?
collective term for all vascular tissue
192
what 2 components are included in ground tissue? (storage, photosynthesis, and support)
1) pith: internal to vascular tissue
2) cortex: external to vascular tissue
193
How are the 3 types of tissues organized -> there order?
vascular tissue in the middle surrounded by ground tissue, with dermal tissue forming an outer protective layer
194
how do plant cells become specialized in structure and function during development?
in multicellular organisms, cells undergo cell differentiation involving changes both in cytoplasm, its organelles, and cell wall
195
what's the structure of parenchyma cells?
thin, flexible walls; most lack secondary walls. Large central vacuole when mature
196
what are the 4 function of parenchyma cells?
1) metabolism: synthesis and store organic products
2) photosynthesis: occurs in leaf chloroplasts
3) storage: starch stored in colorless plastids (roots and stems)
4) fleshy fruit tissue mainly composed of parenchyma cells
197
what is a unique ability of parenchyma cells?
retain the ability to divide and differentiate into other plant cells which is essential for wound repair
198
how many parenchyma cells can regenerate an entire plant?
A single parenchyma cell can regenerate an entire plant
199
what's the structure of collenchyma cells?
elongated cells with unevenly thickened primary walls, grouped in strands for structural support
200
what is the function of collenchyma cells?
provide flexible support to young shoot plants without restraining growth: present in young stems, petioles
201
what is the structure of sclerenchyma cells?
thick, rigid secondary walls rich with lignin that cannot elongate and thus are found only in non-growing regions -> dead at functional maturity leaving behind a supportive skeleton
202
what are the 2 functions of sclerenchyma cells?
1) provide structural support in mature plant tissues
2) strengthens woods, nutshells, seed coats, and fibers
203
what are the 2 types of sclerenchyma cells?
1) Sclereids
2) Fibers
204
what do fibers look like and what do they do?
long and slender with tapered ends and arranged in threads. In leaves they help to reinforce vascular bundles
205
what do sclereids look like, where are they found, and what do they do?
short and irregularly shaped cells found in nut shells and seed coats where they serve to protect the embryonic plant
206
I have thin walls, store starch, perform photosynthesis, and can divide into other cell types. What cell type am I?
parenchyma cells
207
I provide flexible support without restraining growth. what cell am I?
Collenchyma cells
208
what are 2 characteristics of water-conducting cells of the xylem?
1) dead at functional maturity (thickened walls remain)
2) hardened with lignin for support and to prevent collapse
209
what are the 2 functions of water-conducting cells of the xylem?
1) water transport via non-living conduits
2) structural support for plant vascular tissue
210
what are the 2 types of water-conducting cells of the xylem?
1) tracheids
2) vessel elements
211
what types of plants are vessel elements mostly found in?
vessel elements are mostly found in angiosperms
212
where are tracheids found, what do their cells look like and what is their function?
-found in all vascular plants
-long, thin, tapered cells
-water moves through pits (no need to cross thick walls)
213
what's the structure of vessel elements and what is their function?
Wider, shorter, thinner-walled, and less tapered than tracheids, and stacked end-to-end forming vessels. Perforation plates at ends allow free water flow
214
what are 2 characteristics of sugar-conducting cells of the phloem?
1) alive at functional maturity
2) transport sugars and nutrients throughout the plant
215
what are the 2 types of cells in sugar-conducting cells of the phloem?
1) sieve cells
2) sieve-tube elements (in angiosperms)
216
what are sieve cells for?
long, narrow cells for sugar transport
217
what are sieve-tube elements for?
lack nucleus, have ribosomes, vacuole, and cytoskeleton for efficient transport. connected by sieve plates with pores for fluid movement
218
in what type of plants are sieve-tube elements found in?
angiosperms
219
what are companion cells used for in sugar-conducting cells of the phloem?
they're connected to sieve-tube elements via plasmodesmata, nucleus and ribosomes serve both companion cell and sieve-tube element, AND in some plants, they help load sugars into sieve tubes
220
what is indeterminate growth?
Plants grow continuously throughout their life
221
where does indeterminate growth occur?
Growth occurs in meristems, which are regions of perpetually dividing, unspecialized cells so plants can keep growing because meristems keep producing new cells that elongate and differentiate
222
what is determinate growth?
Some organs, like leaves, flowers, and thorns, grow to a certain size then stop: Most animals also show determinate growth
223
where does primary growth arise from?
Arises from apical meristems
224
in herbaceous plants, what parts are from primary growth?
entire plant consists of primary growth
225
in woody plants, what parts are from primary growth?
only newer, non woody parts
226
where are apical meristems located (3 locations)?
Located at tips of roots, shoots, and axillary buds
227
what kind of growth do apical meristems enable?
Enable primary growth (length)
228
what 2 things do lateral meristems give rise to?
1) vascular cambium
2) cork cambium
229
what does vascular cambium add to a plant?
secondary xylem (wood) and phloem
230
what does cork cambium do?
replaces epidermis with periderm (thicker, tougher tissue)
231
what is secondary growth?
Secondary growth = (diameter) in woody plants
232
what are the 2 functions of root caps?
1) root tip covered by root cap to protect the apical meristem
2) secretes polysaccharide slime to lubricate soil
233
what are the 3 zones of root growth in order?
1) zone of cell division: includes apical meristem
2) zone of elongation: root cells elongated (up to 10x their length)
3) zone of differentiation: cells specialize into distinct types
234
what are the 3 primary growth forms in root tissue development?
1) epidermis: protective outer layer
2) ground tissue: mostly parenchyma cells for storage and transport
3) vascular tissue: includes xylem and phloem
235
what does root tissue arrangement look like in eudicots?
xylem is star-shaped with phloem between the arms
The innermost layer of the cortex = endodermis
The outermost cell layer in the vascular cylinder = pericycle
236
what does root tissue arrangement look like in monocots?
the core of parenchyma cells is surrounded by a ring of xylem, and then the phloem
237
where do lateral roots arise from?
Lateral roots arise from the pericycle (layer of cells in the vascular cylinder). Pushes thorough cortex and epidermis to emerge from the root
238
I am where the root apical meristem is found:
ZONE OF CELL DIVISION
239
what meristem produces cells for elongation at the shoot tip?
shoot apical meristem
240
what structure emerges from the meristem and forms new leaves?
leaf primordia
241
what drives shoot lengthening
internode elongation drives shoot lengthening
242
what can grow into lateral shoots?
axillary buds
243
what are axillary buds inhibited by?
apical bud
244
what does apical dominance do?
apical dominance suppresses axillary bud growth via hormonal signals
245
what stimulates branching in plants?
Removing the apical bud (e.g., pruning) stimulates branching
246
where are intercalary meristems in monocots found?
Found at stem and leaf bases in grasses and some monocots
247
How is rapid growth triggered in monocots?
Enable rapid regrowth after damage of intercalary meristems in monocots (e.g., mowing, grazing)
248
what is the stem vascular tissue arrangement in eudicots?
vascular bundles form a ring, xylem is positioned toward the pith (center) and phloem faces the cortex (outer layer)
249
what is the stem vascular tissue arrangement in monocots?
Vascular bundles are scattered throughout the ground tissue
250
Vascular tissue plays a crucial role in a plant's transport system. It consists of two specialized complex tissues...
xylem and phloem
251
the outer layer of the leaf is interrupted by what and what does it allow for?
The outer layer of the leaf is interrupted by stomata, small pores that allow gas exchange (CO2 in, O2 out)
252
What are guard cells used for?
Guard cells regulate opening, controlling water loss via transpiration
253
what type of tissue is mesophyll?
ground tissue
254
what are the 2 types of mesophyll?
1) palisade mesophyll = upper layer
2) spongy mesophyll = lower layer
255
what's the structure of the palisade mesophyll?
tightly packed, elongated parenchyma cells for photosynthesis
256
what's the structure of the spongy mesophyll?
loosely arranged with air spaces for gas circulation, especially near stomata
257
what type of tissue are bundle sheath cells?
Vascular tissue
258
what is the function of bundle sheath cells and what type of cell are they?
Bundle sheath cells (usually parenchyma cells) protect veins and assist in photosynthesis
259
what 2 things do veins do in plants?
1) Veins reinforce leaf structure
2) ensure efficient nutrient distribution
260
what is another word for cambium?
Also called lateral meristem
261
What is cambium made of?
made up of single layers of meristematic cells forming cylinders running the length of a root or stem
262
secondary growth (thickening, wood and bark) arises from what 2 lateral meristems in dicots?
1) vascular cambium
2) cork cambium
263
what's the function of vascular cambium?
adds layers of vascular tissue called secondary xylem (wood) and secondary phloem
264
what does cork cambium do?
replaces the epidermis with periderm, which is thicker and tougher
265
new cells produced to the outside of the meristem differentiate into what?
secondary phloem
266
new cells produced to the inside of the meristem differentiate into what?
secondary xylem
267
what does secondary xylem accumulate as?
Secondary xylem accumulates as wood and consists of tracheids, vessel elements (angiosperms only) and fibers
268
what are 3 components of secondary xylem?
tracheids, vessel elements (angiosperms only), and fibers
269
what kind of plant are vessel elements found in?
angiosperms only
270
what are the characteristics of early wood?
formed in the spring, has thin cell walls to maximize water delivery
271
what are the characteristics of late wood?
formed in late summer, has thick-walled cells and contributes more to stem support
272
what happens to the vascular cambium of perennials in temperate regions?
In temperate regions, the vascular cambium of perennials is inactive through the winter
273
what occurs in cells of seasonal tropical wood?
In seasonal tropical wood, large wet-season cells alternate with small dry season cells
274
where are tree rings visible?
Tree rings are visible where late and early wood meet, and an be used to estimate a tree’s age
275
What is dendrochronology?
analysis of tree ring growth patterns and can be used to study past climate change
276
what 2 things does cork cambium produce?
1) Cork cells to the outside
2) smaller layer of cells called the phelloderm to the inside
277
what 3 components make up the periderm?
The cork cambium, cork cells, and phelloderm make up the periderm
278
what is the function of periderm and what is it a part of?
The periderm protects the woody stem as it increases in girth, and is part of the bark
279
what does secondary growth result from?
Results from cell division in lateral meristems, vascular cambium and cork cambium.
280
what plants have secondary growth?
Occurs in dicots and gymnosperms (not in monocots)
281
what does secondary growth allow for in trees?
Allows trees to get larger in diameter.
282
what does secondary growth add?
Adds transport tissue and provides structural support.
283
What are the 3 tissue systems that extend throughout the body of plants?
1) dermal
2) vascular
3) ground tissue
284
What is the main function of dermal tissue?
Protects plant body
285
What type of tissue is considered dermal tissue?
The epidermis
286
What is the main function of the epidermis?
cells secrete a cuticle that protects the leaves and reduces water loss from the epidermis, keeping plants from drying out
287
What tissue are stomata a part of?
Epidermis which is a part of dermal tissue
288
What does ground tissue include?
includes cells for storage, photosynthesis, and support
289
What are the 3 distinct types of cells in ground tissue?
1) parenchyma
2) collenchyma
3) Sclerenchyma
290
What are 4 characteristics of parenchyma cells?
1) thin, flexible primary walls with intercellular air spaces
2) Most abundant and versatile plant cells
3) Performs the most metabolic function
4) Retain the ability to divide and differentiate (Totipotency)
291
What is totipotency?
the ability of a single plant cell to grow, divide, and differentiate into an entire plant
292
What is a callous and what type of ground cell makes callouses?
A plant callous is a growing mass of unorganized parenchyma cells. Callous cells cover wounds in living plants
293
What are 3 characteristics of collenchyma cells?
1) thicker, uneven primary walls, with thickened corners
2) provides flexible support without restraining growth; no secondary tissues
3) abundant in elongating stems and in the petioles of leaves
294
What are 3 characteristics of sclerenchyma cells?
1) Evenly thick walls
2) rigid due to thick secondary cell walls strengthened with lignin
3) are dead at functional maturity (cannot elongate)
295
What are the 2 types of sclerenchyma cells?
1) fibers = long and slender and arranged in threads
2) sclereids = short, with variable shapes, and function in protection
296
How do Sclerenchyma and collenchyma cells differ?
They both provide support, however, sclerenchyma have secondary cell walls reinforced with lignin meaning that they cannot elongate and are dead at functional maturity. Whereas, collenchyma cells provide flexible support without restraining growth since they have no lignified walls.
297
What does primary growth do to the plant body?
Primary growth extends the plant body
298
What does secondary growth do to the plant body?
secondary growth widens shoots and roots
299
What are 3 primary meristems; 1 for each type of tissue (dermal, vascular, and ground)?
1) dermal = protoderm
2) vascular = procambium
3) ground meristem
300
What are 3 primary tissues; (dermal, vascular, and ground)?
1) dermal = epidermis
2) vascular = primary phloem and primary xylem
3) Ground = ground tissue {pith and cortex}
301
What are 2 lateral meristems; (vascular, and dermal)?
1) vascular = vascular cambium
2) Dermal = cork cambium -> produces periderm in woody plants
302
What are 2 secondary tissues; (only vascular)?
1) secondary xylem
2) secondary phloem
303
What are the 2 major types of meristems?
1) Shoot apical meristem: All aboveground
2) Root apical meristem: All below ground
304
What are the 4 big difference between plant and animal development?
1) Plants continue to grow and develop throughout their lives = indeterminate growth vs. determinate growth of animals. Plants have developmental plasticity
2) plants do not commit cells to gamete production until late into development
3) Organ formation occurs mostly after seed germination
4) Plant do not migrate
305
What is developmental plasticity (regeneration/dedifferentiation) of plants?
they can decide which parts to grow more; developmental plasticity describes the effect of environment on development
306
What are the 3 basic vegetative organs?
1) roots
2) stems
3) leaves
307
What's the difference between the type of root in monocots and dicots (and gymnosperms)?
1) monocot = fibrous root system; adventitious roots arise from the fibrous root system
2) dicots (and gymnosperms) = taproot system where a taproot is the main vertical root; lateral roots or branch roots that arise from the taproot
308
Diversity of roots can be analyzed on 3 levels, what are they?
1) morphological diversity
2) Phenotypic plasticity in response to the environment
3) modified roots that are specialized for unusual activities
309
Why do plants want to have different root morphology?
Biologists suggest that natural selection has favoured structure that minimizes competition for water and nutrients
310
How do roots demonstrate phenotypic plasticity?
Roots show phenotypic plasticity, with forms that change with environmental conditions.
311
What are 4 examples of modified roots (don't function in anchoring and absorbing water and ions from soil)?
1) Prop roots: outside soil support
2) Pneumatophores: gas exchange
3) Adventitious roots: facilitate gas transport and water and nutrient uptake during flooding
4) Vegetable (roots) like carrots: store carbohydrates
312
What is the main function of stems?
supporting and elevating leaves and flowers, thus maximizing photosynthesis and facilitating dispersal of pollen and fruit
313
How do plants differ in their shoot systems (diversity) due to environmental conditions?
1) Competition for light favours taller shoot systems
2) Dry, windblown habitats favour short stems that are more anchored to the soil
314
What are 5 examples of modified stems?
1) cactus = stores water
2) Stolon = produce new individuals at nodes aboveground (asexual reproduction)
3) Rhizomes = produce new individuals at nodes belowground (asexual reproduction)
4) Tubers = stores carbs
5) Thorns = protection
315
What is the main function of leaves?
providing surface area for absorbing sunlight and exchanges gases (the main photosynthetic organ)
316
What is the different vein arrangement of monocots and dicots?
1) monocots = parallel veins
2) dicots = branching veins
317
How do leaves differ in morphological diversity?
Not all leaves are thin, with a large surface area (Plants that thrive in deserts and in cold, dry habitats tend to have small, needle-like leaves)
318
True or false: leaves grow continuously?
FALSE: do not grow continuously
319
How do leaves exhibit phenotypic plasticity in regards to their environmental conditions?
1) Sun leaves have a relatively small surface area which reduces water loss in areas of the body where light is abundant
2) Shade leaves are relatively large and broad because they want to maximize the absorption of light
320
What are 6 examples of modified leaves?
1) onion leaves = store food
2) aloe vera = store water
3) pea tendrils = aid in climbing
4) poinsettia = attract pollinators
5) pitcher plant leaves = trap insects
6) cactus spines = protection against predators
321
What's the difference between spines and thorns?
spines = modified leaves and thorns = modified stem
322
What are 4 epidermal cells that have differentiated?
1) Root hairs: expands surface area
2) Trichomes = protection against disease and insects
3) Guard cells = form stomata (pores) for gas exchange: stomata determine form and ecology. Stomata are necessary for a plant's success on land. All land plants have stomata except for Liverworts which have pores
4) Pavement cells: protect underlying tissues and prevent water loss
323
What is the model plant for dicots?
arabidopsis
324
What is the model plant for monocots?
Brachypodium
325
How do the epidermis' of dicots and monocots differ?
1) dicots: squiggly epidermis with kidney bean shaped guard cells, scattered distribution
2) monocots: rectangular epidermis with dumbbell shaped stomata
326
What did the recent availability of genome sequences and reverse genetic tools for model monocots and basal land plants allow for?
This allowed for the examination of the conservation of genes important in stomatal development
327
Where are the stomata of bryophytes located (except for liverworts = no stomata)?
Stomata in bryophytes are uniquely located on sporangium (bot leaves of vascular plants)
328
What is the role of stomata in bryophytes?
they play a role in the maturation of the reproductive sporophyte capsule
329
True or false: The production of stomata on the sporophytes of mosses and hornworts appears to require much simpler cellular processes than that of dicots?
TRUE
330
What are 2 stomata separated by?
2 stomata are separated at least by one non-stomatal cells in nearly all plant species
331
why is keeping ‘one cell spacing rule’ between stomata important (occurring in most dicot leaves)?
This spacing is hypothesized to be important for efficient gas exchange
332
True or false: all stomata across different plant families are the same?
FALSE: there is diversity of stomatal morphologies and distributions across different plant families
333
What 2 things led to a change in the diversity within populations and the modification of the genomes of crop plants?
1) cultivation
2) selection (selective breeding)
334
What 4 things have occurred to corn during its domestication?
1) cob size increased
2) The hard casings around many grains were eliminated; Teosinte, the wild relative of maize, has hard coverings over each grain. Humans selected against these during maize domestication.
3) Decrease in branching and increase in seed size
4) Seeds that don't break off easily
335
Why is more branching bad?
The plants are using more energy, less branching = more energy placed toward growing the crop -> edible part.
336
What are 2 categories of crops created through genetic engineering?
1) Herbicide-resistant GM crops
2) GM crops for direct consumption
337
What % of GM crops are used to combat weeds?
~70% of all GM crops to combat weeds for crops
338
What is the most widely used GM herbicide-resistant crops?
Round-up Ready Crops: genetically modified to be resistant to the herbicide roundup. Roundup is the brand name of a herbicide produced by Monsanto.
339
What is the second most prevalent GM modification?
Bt crops: contains Bacillus Thuringiensis that coded for the crystal protein which are toxic to some insect larvae. The development and commercialization of insect-resistant transgenic Bt crops
340
What are 2 examples of GM crops for direct consumption?
1) Golden rice: Rice variety designed to synthesize beta-carotene (vitamin A precursor)
2) Hawaiian GM Papaya: papaya ringspot virus severely infect non-GM variety surrounds the GM papaya.
341
How can genetic engineering accelerate crop breeding?
Agrobacterium-mediated transformation allows for a single gene to be introduced into a genome. This method can be faster than conventional breeding
342
What is the main threat to plant diversity?
habitat destruction which is generally accompanied with the loss of the animal species that the plants supported
343
How much area is cleared in tropics each year?
55,000 km2 cleared each year
344
At the current rate of habitat loss, what % of Earth's species will become extinct in the next 100-200 years?
50%
345
What type of cell makes up both the palisade and spongy mesophyll and what do they do?
The palisade and spongy mesophyll cells of leaves are parenchyma cells that function in photosynthesis
346
Where do we find collenchyma cells; where on the plant and what type of plant?
we find them on the underside of the epidermal layer in monocot stems
347
What type of cells make up tracheids and vessel elements?
tracheids and vessel elements are specialized sclerenchyma cells of the xylem that function in the long distance transport of water and minerals
348
True or false: all 3 types of tissues, dermal, vascular, and ground, are continuous throughout the body of the plant?
TRUE
349
What types of plants are tracheids and vessel elements found in?
xylem cell, tracheids, are found in all vascular plants, whereas, vessel elements are common in most angiosperms and few gymnosperms
350
How do sieve-tube elements in phloem function when they have no organelles?
they maintain function because of their close association with companion cells which helps to maintain the plasma membrane of the sieve tube element
351
Where do lateral roots branch out of in eudicots and monocots to exploit more resources?
lateral roots branch out of the pericycle
352
What is the correct sequence of plant tissues from the center outward?
Pith, primary xylem, secondary xylem, vascular cambium, secondary phloem, primary phloem, cork cambium, cork, bark
353
What's the difference between dicot embryos and monocot embryos?
Monocots = 1 cotyledon
Dicots = 2 cotyledons
354
What's the difference between dicot and monocot stems?
Monocot = scattered bundles of vascular tissue
Dicots = vascular tissue arranged in concentric circles
355
What's the difference between dicot and monocot Leaf venetian?
Monocot = parallel veins
Dicot = branching veins
356
What's the difference between dicot and monocot root systems?
Monocot = fibrous root
Dicot = Taproot (main root)
357
What's the difference between dicot and monocot flowers?
Monocot = floral organs usually in multiples of 3s
Dicot = floral organs usually in multiples of 4 or 5
358
What's the difference between dicot and monocot pollen?
monocot = pollen grain with single furrow or pore
Dicot = pollen grain with 3 furrows or pores
359
What is a simple pistil?
single carpel or several unfused carpels
360
What is a compound pistil?
several fused carpels
361
What's an inflorescence?
a cluster of flowers on a branch or a system of branches
362
Fruits are only borne on what type of flowers?
carpellate flowers
363
What are hypogynous flowers?
flowers that have ovary in superior position above the receptacle
364
What are perigynous flowers?
flowers that have ovary within the receptacle, but not enclosed
365
What are epigynous flowers?
flowers with ovaries enclosed within the receptacle
366
What are 3 examples of simple fleshy fruits?
berries, drupes and pomes
367
What are simple fleshy fruits a product of?
All are the products of a single flower from a single carpel or compound pistil
368
What are berries the product of?
berries are the products of compound pistils
369
What 3 fruits do berries include?
Grapes, tomatoes, and blueberries
370
What are modified berries?
include fruit with leathery, aromatic rind like citrus
371
What may simple dry fruits be categorized as?
dehiscent or indehiscent
372
What does the ovary wall in dehiscent fruit do?
Breaks open to liberate seeds
373
What does the ovary wall in indehiscent fruit do?
ovary wall does not break open, instead, the entire dry fruit disperses as one intact unit
374
How is an aggregate fruit formed?
formed from a single flower with many unfused carpels
375
What's a common example of an aggregate fruit?
raspberry flower
376
What does a multiple fruit develop from?
they develop from an inflorescence; tight cluster of tiny flowers produces a fruit that's actually a dense cluster of many small fruits
377
What is an example of a multiple fruit?
Mulberry
378
What are 5 subcategories in the category of simple fleshy fruit?
1) drupe
2) pepo
3) berry
4) pome
5) Hesperidium
379
How do you identify a drupe?
Has a pit
380
How do you identify a pepo?
hard, papery, dry pericarp = coconut
381
How do you identify a berry?
fleshy inside with some seeds
382
How do you identify a pome?
Apple :/
383
How do you identify a Hesperidium?
leathery, aromatic rind with fleshy segmented interior
384
What are 5 subcategories within the category of Simple dry fruit?
1) achene
2) nut
3) capsule
4) legume
5) silique
385
How do you identify an achene?
dry, one-seeded fruit lacking special seams that split to release the seed = dandelion
386
How do you identify a nut?
it's a nut
387
How do you identify a capsule?
dry fruit that opens when ripe
388
How do you identify a legume?
It's a pod = green beans
389
How do you identify a silique?
separates at maturity
390
What kind of fruit is arabidopsis?
silique = simple dry fruit
391
What are 2 subcategories within the category compound fruit?
1) Multiple
2) Aggregate
392
How do you identify an aggregate fruit?
Multiple ovaries = raspberry
393
How do you identify a multiple fruit?
pineapple, blackberry, etc.
394
What do accessory fruits develop from?
fruit develops from adjacent tissue exterior to the carpel -> receptacles or sepal
395
What's an example of an accessory fruit?
Strawberry: fleshy part is derived from modified receptacle tissue
396
What is the function of the petiole?
attaches leaves to stems
397
What does the pedicel do?
attaches flower to stem
398
Why do petals quickly abscise soon after fertilization?
The petals lack a cuticle and are therefore a liability to plants bc of excess water loss
399
What is the name of the meristematic cells that form the vascular cambium?
cambial cells
400
What cells arise when cambial cells divide?
one cell remains a meristematic cell called an initial and other cell becomes a derivative
401
What does the derivative cell do if it's inside the vascular cambium?
differentiates into a cell of the xylem system
402
What does the derivative cell do if it's outside the vascular cambium?
becomes a cell of the phloem system
403
What do elongated initials produce and what do shorter initials produce?
elongated = produce sclerenchyma fibers
shorter = produce vascular rays
404
What is the function of vascular rays or ray cells?
these radial parenchyma cells serve as conduits for movement of substances from the secondary xylem to secondary phloem
405
What makes bark impervious to water and pathogens?
suberin lining
406
What are lenticells?
like stomata, but without guard cells, oxygen diffuses through these apertures a very short distance to find living cells. Stud the entire length of tree trunks since cork cambium prevents a lot of oxygen from diffusing into the tree so this is how living cells get o2
407
What 2 things does bark consist of?
1) secondary phloem tissue
2) all layers of the periderm
408
What do the layers of periderm consist of?
cork cambium
409
Cork cambium is a lateral meristem that produces cells inside and outside of the cork cambium. What are the cell called on the inside of cork cambium and what are they called on the outside of cork cambium?
Inside = cork parenchyma cells
Outside = cork cells
410
411
