Exam 2 Flashcards
(262 cards)
1
Q
The floral structures are attached in a circle of the flower where are the sepals and petals
A
The outer layer of the circle contains sepals which are usually green and enclose the flower before it opens
The next layer after the sepals are removed there are the petals these are very noticeable and attract pollinators and these petals are the key to the success of angiosperms
2
Q
What is revealed when the flower petals are removed
A
The stamen filiments
3
Q
What is at the top of each stamen filament
A
The anther
4
Q
Describe the anther
A
A sac containing the male sporangia this will eventually release pollen
5
Q
Where is the carpel located and what does it do
A
The structure located at the centre of the flower
This is the female reproductive structure including the ovary
A unique adaptation which enclosed the ovules
Each ovule contains a sporangium that will produce a female gametophyte and eventually become a seed
The ovary will mature into a fruit which aids in seed dispersal
6
Q
Angiosperms are a group of plants that are
A
Sporophyte dominant
7
Q
The gametophyte generation of angiosperms is produced where
A
Its body
8
Q
Where does meiosis occur in angiosperms
A
Within the anther of the flower
This produces haploid spores which undergo mitosis
These will form the male gametophyte (pollen grains)
9
Q
Meiosis in the ovule produces what
A
A haploid spore that undergoes mitosis
This forms the few cells of the female gametophyte
One of these cells is destined to become an egg
10
Q
Pollination of angiosperms occurs when
A
A pollen grain lands on the stigma
The pollen grain is carried by either wind or an animal
A tube grows from the pollen grain to the ovule and a sperm fertilizes the egg (same as in gymnosperms)
This forms a zygote
11
Q
In angiosperms a seed develops from each ovule and each seed consists of
A
An embryo surrounded by a seed coat and a food supply
The embryo is a new sporophyte
12
Q
As the seed develops in angiosperms the ovaries wall thickens and forms what
A
The fruit that encloses the seeds
13
Q
When conditions are favourable for the angiosperms the seed germinates and …
A
The embryo grows it uses the food supply from the seed until it can begin photosynthesis
Eventually it develops into a mature sporophyte completing the life cycle
14
Q
What is a key adaptation of angiosperms
A
The flowers attract animals which carry pollen more reliably then wind
They are also able to produce seeds very rapidly - fertilization occurs just 12 hours after pollination
15
Q
Describe fruits
A
The ripened ovary of the flower
Aids in seed dispersal
16
Q
Explain the stages of fruits
A
During development the fruits remain green and thus camouflaged
When ripe fruit becomes bright this attracts animals
When the fruit is eaten the seeds will be deposited by the animal
17
Q
Not all flowers have colourful accessories and sweet scents what is an example of this
A
Red maple
Has many anthers but no petals and relies on wind for pollination
To work massive amounts of pollen must be produced to endure that some make it to another plant and fertilization takes place
18
Q
The columbine has an elaborate flower vibrantly coloured what are the advantages and disadvantages
A
This is associated with a high energy cost
This investment pays off when a pollinator carries the plants pollen to another flower
Because the pollinator is attracted to the flower
19
Q
What supports the fact that about 90% of angiosperms use animals for pollination
A
Animals visit the flowers in search of a meal
Flowers provide meal in form of nectar which is a high energy fluid
The colourful petals and strong fragrance mark the plant as a good source
20
Q
Two major groups of angiosperms are what
A
Monocots and
Eudicots
21
Q
How are angiosperms classified into monocots and eudicots
A
According to the first leaves that appear on the plant embryo
These embryonic leaves are called seed leaves or cotyledons
22
Q
How many cotyledon’s do monocots have and how many do eudicots have
A
Monocots - 1 cotyledon
Eudicots - 2 cotyledon
23
Q
Give examples of monocots
A
Large group of related plants including lilies and orchids
24
Q
What are the characteristics of monocots
A
Leaves with parallel veins
Stems contain vascular tissues arranged in scattered bundles
Flowers contain petals and other parts in multiples of three
Roots from a shallow, fibrous system spreading out below the soil surface ; this arrangement permits a huge surface area which reduces erosion
25
Give examples of eudicots
Included most shrubs and tress crops fruits and vegetables
26
Most angiosperms are eudicots or monocots
Eudicots
27
What are the characteristics of eudicots
```
Multi-branched network of veins
Vascular bundles arranged in a ring
Petals and other parts are found in arrangements of four or five
Root is large and vertical -> taproot
Goes deep into the soil
```
28
The plant body contains three basic organs
1) roots
2) stems
3) leaves
Each are composed of different tissues
Organ structure correlates nicely with function
29
What are the two systems of a plant
Root system
| Shoot system
30
Describe the root system
Anchors the plant in the soil
Absorbs and transports minerals and water
Stores food
Near the root tips is an abundance of root hairs
- increases surface area for absorption of water and minerals
31
Describe the shoot system
Made of stems and leaves
| Also reproductive structures such as flowers
32
What are the four parts of the shoot system
Stems
Nodes
Internodes
Leaves
33
Describe the stems
Above ground
| Supports leaves and flowers
34
Describe the nodes
Point at which leaves are attached
35
Describe the internodes
Portions of the stem between the nodes
36
Describe the leaves
Main photosynthetic organs
| Composed of a flattened blade and a stalk called a petiole which joins the leaf to the node of the stem
37
What are the two types of buds
Terminal buds
| Axillary buds
38
Describe terminal buds
At the apex tip of the growing stem
| Has developing leaves and a compact series of nodes and internodes
39
Describe axillary buds
These are within the angle between the leaf and the stem
| Usually dormant
40
Describe apical dominance
Hormones produced by the terminal buds inhibit their growth
41
Axillary buds allow concentrating resources toward growing taller and increases the plants what
The plants exposure to sunlight and is important when vegetation is dense
42
Under some conditions the axillary buds begin to grow and what occurs
The growth removes the terminal bud and often stimulates the growth of the axillary bud
43
What are the three modified stems
Horizontal stem (runner)
Rhizomes
Bulbs
44
Describe horizontal stem
Aka runner
Grows along the ground surface
Allows the plant to reproduce asexually
45
Describe rhizomes
Horizontal stems that grow either right below or along the surface of the soil
They store food and may also spread and form new plants
Potato plants have rhizomes which end in enlarged structures called tubers which are specialized for storage (the potato)
46
Describe bulbs
Underground shoots which contain swollen leaves for food storage
47
What are the two types of modified leaves
Tendrils
| Spines
48
Describe tendrils
The tips are coiled around a stem
| This helps the plant to climb such As in a grapevine
49
Describe spines
Of a cactus are a modified leaf that protects against being eaten by animals
50
Define a tissue
Group of cells with a common structure function or both
51
Define a tissue system
Composed of one or more functional units within a plant
52
The plant root stem and lead are all made of three tissue systems
1) dermal tissue
2) vascular tissue
3) ground tissue
The three tissue systems have different arrangements in different organs
53
What are the four types of eukaryotes
Protists
Plants
Fungi
Animals
53
Explain protists
```
Eukaryotes
Unicellular (mostly)
Diverse group and live in diverse habitats
Some are autotrophic = algae
Some Heterotrophic = protozoans
Some are both = mixotrophs
```
54
Explain protists diverse habitat
Most are aquatic
Can be found almost anywhere with water ie) damp soil and ponds
Some protists inhabit host organisms
55
Define endosymbiosis
| Give an example
Refers to one species called an endosymbiont living within another species
Ie) termite endosymbiont leaves in the gut of a termite and digests the tough cellulose in the wood diet of the termite
They live in harmony
56
Define symbiosis
Refers to a close relationship between organisms of two or more species
57
What is the simplest group of eukaryotes
Protists
58
What are the 5 subgroups of protists
1) Chromalveolata
2) Rhizaria
3) Excavata
4) Unikonta
5) Archaeplastida
59
How did eukaryotes originate
The theory is endosymbiosis
| When small prokaryotes established residence in larger prokaryotes
60
What evidence supports the endosymbiosis theory of eukaryote origin
There are similarities between prokaryotes and present day mitochondria and chloroplasts
61
Who is said to have evolved first
Heterotrophic eukaryotes
Or
Autotrophic eukaryotes
Heterotrophic
| Have no chloroplast and can not preform photosynthesis
62
How where autotrophic eukaryotes said to have originated
When an individual engulfed an autotrophic Cyanobacterium (these are photosynthetic bacteria)
Eventually the Cyanobacterium turned into a chloroplast
This later created green and red algae
63
What happened to the red and free algae during the evolution of protists and eukaryotes
The green and red algae became endosymbiont when engulfed by heterotrophic eukaryotes
64
Define secondary endosymbiosis
The process when an autotrophic eukaryote protist became endosymbiotic in a heterotrophic eukaryotic protist
65
What are the five types of chromalveolates
1) diatoms
2) dinoflagellates
3) brown algae
4) water molds
5) ciliates
66
What are the two types of Rhizarians
1) foraminiferans
| 2) radiolarians
67
What are the two types of unikonts
1) plasmodial slime molds
| 2) cellular slime molds
68
What are the two types of archaeplastids
1) red algae
| 2) green algae
69
Describe diatoms
```
Unicellular
Glassy cell wall with silica and has two halves of the cell wall that fit together like a box
Autotrophic
Found in marine and freshwater
Produce important food for aquatic life
They form their food in sugar droplets
```
70
What are the two advantages of diatoms sugar and oil droplets
Rich source of energy
| Oil makes the diatoms buoyant and keeps them floating near the surface of the water where sunlight is plentiful
71
Fossilized diatoms form what
Sediment
| Diatomaceous earth
72
Describe dinoflagellates
Found on marine and freshwater plankton
| Some are hetero/auto/mixotrophic
73
What happens when dinoflagellates bloom
They can cause warm coastal waters to turn pinkish orange which is called the red tide
And produce toxins which have killed large quantities of fish
74
Describe brown algae
```
Large and complex
Autotrophic
ALL Are multicellular
Most are marine
What we commonly call seaweed
(Kelp)
```
75
What is brown algae brown
Due to their pigments in their chloroplasts
76
Describe water molds
```
Heterotrophic
Unicellular
Fungus like
Decompose dead plants and animals in freshwater habitats
Some grow on the skin and gills of fish
```
77
Describe ciliates
Large and diverse group
Use cilia for movement and feeding
Unicellular
Heterotrophic and mixotrophs
78
What is an example of ciliates
Paramecium
79
What do chromalveolates also include
| What do these cause and how are they transmitted
Plasmodium
| Cause malaria and transmitted by mosquitoes
80
What are Rhizarians referred to and why
Amoebas
| Because they move and feed using pseudopodia
81
Why are Rhizarians pseudopodia different then other amoebas
Their pseudopodia is thread like rather then the typical lobe like
82
Describe foraminiferans
Found in ocean and freshwater
| Have tests
83
Define tests
Tests are porous shells composed of organic material hardened by calcium carbonate
Pseudopodia extend through the small holes in the test
84
What do fossilized tests form
Sedimentary rock
85
Describe radiolarians
Produce an internal skeleton made of silica
The cell is also surrounded by a test of organic material
Many species are marine
When they die they settle at the bottom of the ocean and become sediments
86
Describe excavata
Autotrophic heterotrophic mixotrophs
Likely the most ancient type of eukaryote
Has a modified mitochondria with no electron chain
Are anaerobic (use glycolysis for ATP)
87
Who are likely the most ancient eukaryotes
Excavata
88
What are some examples of excavatas
```
Giardia intestinalis
-waterborne parasite causes diarrhea
Trichomonas vaginalis (via sex)
Trypanosoma spp (via bugs)
Euglena spp (found in pond water)
```
89
Define a parasite
Derive nutrition from their host, and the host is harmed during the process
90
Describe unikonts
```
Use pseudopodia to move and feed
Includes:
-free living amoebas
-some parasitic amoebas
-2 types of slime molds
```
91
Describe plasmodial slime molds
Commonly found where these is moist decaying organic matter
Brightly pigmented
Unicellular
DIFFERENT then the plasmodium that causes malaria
Uses pseudopodia
Moves cytoplasm as one in a pulsing flow to move nutrients and oxygen
92
What happens when food is limited for the plasmodium
The plasmodium stops growing and differentiates into reproductive structures that produce spores
When conditions are favourable the spores release haploid cells that fuse to form a zygote allowing the life cycle to continue
93
Describe cellular slime molds
Common on rotting logs and decaying organic matter
| Usually they exist as solo amoeboid cells
94
What happens to cellular slime molds when nutrients are scarce
They swarm together forming a slug like clump of cells that travels around for a short time
Some of these cells will then dry up and form a stalk
95
What does the stalk do for cellular slime molds
Supports an asexual reproductive structure
| In this structure cells develop into spores
96
Describe archaeplastids
Mainly autotrophic
| Red green algae and land plants
97
Describe red algae
Live in warm coastal waters of the tropics
Red because of an extra pigment that masks the green
Most are multicellular
Most are soft bodied but some have hard deposits on their cell wall
98
Where do you find hard bodied red algae
On coral reefs
99
Describe green algae
Green coloured
Unicellular
Colonial and multicellular members
Generally have complex life cycles
100
What is an example of a green algae with a complex life cycle
Multicellular Ulva
101
Complex life cycle of multicellular green algae is characterized by what
By an alternation of generations
102
How is green algaes life cycle an alternation of generations
Multicellular diploid form (2n) alternates with a multicellular haploid (n) form
This alternation of generations occurs in many multicellular algae as well as plants
103
Define gametophytes
Multicellular haploid form
104
Define sporophytes
Multicellular diploid form
105
Explain the evolution of multicellularity
1) an ancestral colony of flagellated protists may have formed (when a cell divided and offspring remained attached)
2) cells of the colony may have become slightly specialized and interdependent (more efficient)
3) additional specialization may have led to differentiation in between sex cells and non reproductive cells
106
Why was early life on land perfect for plants
There was an abundance of sunlight and carbon dioxide
| There were very few pathogens and plant eating animals
107
What differentiates multicellular algae from multicellular plants
Plants under went certain key adaptations that needed to take place in order for them to be able to live on dry land
108
What are some of the key differences between algae and plants
Algae
- anchored but no ridged tissues supported by water contains minerals and CO2 directly from the water the entire organism has access to light, flagellated sperm swim to the egg and offspring are also dispersed by water
Plants
- surrounded by air and has mechanism to keep water in cells, gets nutrients from soil and air, has to support itself, has to reproduce without the use of water
109
What are the four plant adaptations for life on land
1) maintaining moisture
2) obtaining resources from very different environments
3) supporting the plant body
4) reproduction and dispersal
110
Explain the plants adaptation to maintain moisture
The portions of land plants that are above the ground are covered with a waxy cuticle that prevents water loss
CO2 and o2 cannot diffuse across the cuticle so the pores on the leaves function in gas exchange
111
What are the pores called on the leaves of plants and how are they regulated
Stomata
Surrounding cells regulate the opening and closing of the pores
Usually stomata is open during the day allowing gas exchange and closed during the night to prevent water loss
112
Explain the plants adaptations to obtaining resources from different environments
Plants must obtain resources from both the soil and the air
Water and nutrients are found in the soil
Light and CO2 is found in the air
Roots stems and leaves help to fulfill these requirements
113
Describe the roots and how they help in obtaining resources from different environments
Provide anchorage
| Absorb water and mineral nutrients from the soil
114
Describe the stems and leaves and how they help to obtain resources from different environments
The leaves capture CO2 which enables photosynthesis
Apical meristems are growth producing regions that are found near the tips of both roots and stems
Elongation and branching act to maximize exposure to resources found within the soil and air
115
How do vascular and avascular tissues help obtain resources from different environments
The xylem functions to move water and minerals up from the roots
The phloem functions to move sugars up and down the plant
Avascular
-few plants are avascular and are restricted with height because they have limited means to distribute water and minerals from the soil and air
116
Define apical meristems
Growth producing regions that are found near the tips of both roots and stems
117
What are the two types of tissues in plants
Vascular
| Avascular
118
What are the two types of vascular tissues
1) xylem - move water up from roots and are composed of dead and living cells
2) phloem - move sugars up and down the plant and composed of ONLY living cells
119
Explain the plants adaptations of supporting the body
They must be able to hold themselves up against gravity
| Cell walls of some plants are thickened and reinforced by a chemical called LIGNIN
120
What is the chemical called that reinforces and thickens the cell wall what happens when there is an absence of this chemical
Lignin
| Causes a height limitation
121
Explain a plants adaptations of reproduction and dispersal
Plants must be able to keep their gametes developing embryos from drying out in the air
122
Where do mosses and ferns produce gametes
Within the female and male gametangia
123
Define the gametangia
Structures made of a protective jacket of cells surrounding the gamete producing cells
124
Why can mosses and ferns only reproduce in moist environments
Because male gametes are released and swim to the female gametangium where the egg remains and this requires water!
125
What do pines and flowering plants have for reproduction
Pollen grains
126
Describe pollen grains
Structures that contain the sperm producing cells
| These are brought close to the egg by wind and animals this does not require moisture
127
What occurs to the zygote in all plants
The zygote (fertilized egg) develops into an embryo while still attached to the parent plant
128
Define the embryophyte
What the embryo is called when multicellular and dependent
| Key difference between plants and algae
129
What does the haploid generation produce during the alternating generation
Eggs and sperm
130
What does the diploid generation produce during the alternating generation
Produces spores within a structure called a sporangium
131
What can spores develop into
A new organism without fusion with another cell
132
What types of plants uses spores for dispersal and what plants use seeds
```
Mosses/ferns= spores
Pines/flowers= seeds
```
133
Define seeds
Elaborate embryo containing structures that protect the embryo from elements that are dispersed by wind or animals
134
Plants that do not use seeds to disperse their offspring are referred to as what
Give an example
Seedless plants
| Ie) mosses and ferns
135
Define bryophytes
Seedless avascular plants that were first to arise
136
Describe bryophytes and give an example
Lack true roots and leaves
They resemble all other plants because they have apical meristems and embryos that develop while attached to the parent plant
They do not have lignin so don't grow very tall
Found in spongey mats or growing in dense mats
Ie) mosses
137
Describe vascular plants
Have lignin in cell walls
| Provide strong support allowing for them to stand straight and grow tall
138
What are the two primary groups of vascular plants
Seedless vascular plants
| Seeded vascular plants
139
Describe seedless vascular plants
Includes ferns
These have well devolved roots and stems common in forests but are more diverse in the tropics some can grow several meters tall
Do not require moisture for reproduction
They disperse their offspring as spores carried through the air
140
Describe seeded vascular plants
Accounts for more then 90% of the species
| Seeds and pollen improved the plants ability to live on land
141
Define seeds
Contain an embryo and a food supply contained within a protective coating
Package of survival
Facilitated the dispersal of plant embryos over wide distances
142
Define pollen
Brings sperm producing cells into close contact with egg-producing parts
Water is not necessary for fertilization
Pollen is able to travel large distances
143
What are the two main groups of seeded plants
1) gymnosperms (earliest seed plants)
| 2) angiosperms
144
Define gymnosperms
The earliest lineage of seeded plants
Gymno = naked
Seeds are not produced in chambers
145
What is the largest group of gymnosperms
Conifers
| Cone bearing trees ie pine
146
Define angiosperms
The most recent episode in plant evolution
These are flowering plants
Angio= container
Refers to the fact the seed is produced within a specialized chamber
Flowers are complex reproductive structures that develop seeds within protective chambers
147
Summarize the evolution of plant adaptations
1) dependent embryos are present in all plants
2) lignified vascular tissues mark a lineage that gave rise to most vascular plants
3) seeds are found on all gymnosperms and angiosperms and dominate the plant kingdom today
4) flowers are the makers of the angiosperm lineage
148
What are the stages of the plant life cycle
1) haploid gametophyte plants produce gametes (sperm and egg) by mitosis
2) fertilization produces a diploid zygote
3) the zygote divides by mitosis and develops into a multicellular diploid sporophyte plants
4) the sporophyte produces haploid spores by meiosis
5) spore then develops by mitosis into a multicellular haploid gametophyte
149
Mosses are___. The cushiony green growth of the moss is the _____
Gametophyte dominant
Gametophyte
150
5 stages of moss life cycle
1) gametes develop in male and female gametangia
2) after fertilization the zygote remains in the gametangium
3) in the gametangium the zygote divides by mitosis
4) meiosis occurs in the sporangia at the tips of the sporophyte stalks
5) spores undergo mitosis and develop into gametophyte plants
151
Where is the gametangia usually located in mosses
On separate plants
152
Flagellated sperm swims through a water film to reach the egg in the female _____
Gametangium
153
In mosses after the zygote divides by mitosis what does it develop into
Sporophyte embryo and then mature sporophyte
| The sporophyte remains attached to the gametophyte
154
Following meiosis in moss the haploid spores are released from the ____
Sporangium
155
Describe ferns and it's life cycle
Sporophyte dominate
1) gametophyte is very small (heart like shape and sperm needs moisture)
2) the zygote remains on the gametophyte
3) the zygote develops into an independent sporophyte
4) within the clusters of sporangia cells undergo meiosis producing haploid spores which are then released
5) spores develop into gametophytes by mitosis
156
In gymnosperms what is the specialized structure within the sporophyte that all stages of reproduction occur
The cone
| Each scale of the cone contains sporangia which produce spores by meiosis
157
What are the two types of cones that pine trees have which produce spores
Pollen cones
| Ovulate cone
158
Describe the pollen cone
Produces male gametophytes
Smaller cones
Contain sporangia which produce many haploid spores by meiosis
Male pollen grains (gametophytes) develop from these spores
Mature pollen cones release millions of microscopic pollen grains in clouds and are carried by wind
They contain cells that will develop into sperm if they land on a cone containing a female gametophyte
159
Describe the ovulate cone
Produces the female gametophyte
Larger cone
Each scale contains a pair of ovules
Each ovule contains a sporangium covered by a protective covering
160
What is the protective covering around the sporangium in the ovule called
Integument
161
When does pollination occur in gymnosperms
When a pollen grain lands on an ovulate scale and enter an ovule
Following pollination the scales grow together sealing the cone until the seeds are mature
Now meiosis occurs in a spore mother cell within the ovule
162
Over the course of months how many haploid spores will survive and develop into the female gametophyte in gymnosperms
ONE
this gametophyte will produce eggs
A tiny tube grows out of the pollen grains and this tube digests its way through the ovule and eventually sperm is released near an egg
163
How long after pollination in gymnosperms will fertilization usually occur
More then a year after pollination
164
All eggs in an ovule are usually fertilized but ____
Only one of these zygotes will fully develop into a sporophyte embryo
165
Under favourable conditions the seed will do what in gymnosperms
Will germinate and it's embryo will develop into a pine seedling
166
The ovule will mature into a seed in gymnosperms and do what
The seed contains the embryos food
The food supply is the remains of the female gametophyte
The seed coat is the ovules integument
Typically seeds are shed two years after pollination
The seeds disperse by wind
167
Where is the site of pollination and fertilization on angiosperms
The flowers
| They house separate male and female sporangia and gametophytes
168
How do flowers differ from pine cones
Each structure of the flower is highly specialized for very different functions
169
Describe the dermal tissue system
Forms an outer protective covering
| First line of defence against physical damage and infectious organisms
170
What does the dermal tissue system consist of
Epidermis - single layer of tightly packed cells
Cuticle - waxy outer covering atop the epidermis protects against water loss
171
Describe vascular tissue
Composed of xylem and phloem tissues
| Provides support and long distance transport
172
Describe ground tissue
Not dermal or vascular
Accounts for the bulk of a young plant
Fills the space between the vascular tissue and the epidermis
This system function is support storage and photosynthesis
173
ground tissue internal to the vascular tissue is the
Pith
174
Ground tissue external to the vascular tissue is the
Cortex
175
Describe the vascular cylinder
| Two types of cells
Vascular tissue system in the centre of the root
Xylem cells
Phloem cells
176
Xylem cells of dicot are found where
Radiate from the centre like spokes of a wheel
| Ring of xylem cells found in root of monocots
177
Phloem cells of dicot are found where
Fill the wedges between the spokes
| Ring of phloem cells found in root of monocots
178
The region between the vascular cylinder and the epidermis consists entirely of ___
Correct
179
Define cortex cells
Store food and starch and take up minerals that have entered the root via the epidermis
180
Define the epidermis
The inner layer of the cortex
A cylinder that is one cell layer thick
A selective barrier that determines which materials can pass between the rest of the cortex and the vascular tissue
181
Eudicots and monocots have different stem arrangements explain:
Both have vascular tissues arranged in vascular bundles
Monocots - has vascular bundles scattered throughout the ground tissue
Eudicots - has vascular bundles arranged in a ring
182
What do eudicot stems have unlike roots
| Are monocots the same
Has both a cortex region and a pith region
No they are not divided into pith and cortex regions
183
Describe the stomata
Interrupt the epidermis
Allow gas exchange
Each stoma is bordered by two guard cells that regulate the size of the stomata opening
184
The ground tissue between the leaf is called what and is between what
Mesophyll
Between the Upper and lower epidermis
Consists predominantly of photosynthetic parenchymal cells
Where chloroplasts are located
185
Eudicots and monocots have vascular tissue on the leaf made up of a network of ___
Veins
186
Each vein has a vascular bundle composed of __ and __
| What does this do
Xylem and phloem
| Gives leaf it's shape and helps carry out photosynthesis by circulating
187
What are the three structures that distinguish plants from other eukaryotes
Chloroplasts
Central vacuole -contains fluid for shape
Cell wall
188
Many plants have two cell walls what are they
Primary cell wall
(Laid down first)
Secondary cell wall
(Ridged laid down second and is between the plasma membrane and the primary cell wall)
189
Define the middle lamella
A sticky layer that holds the primary cell walls of adjacent cells together
190
What are pits
Regions where the cell wall is relatively thin allowing the migration of water between adjacent cells
191
Define plasmodesmata
Channels of communication and circulation between adjacent plant cells
192
What are the five types of plant cells
1) parenchymal cells
2) collenchyma cells
3) sclerenchyma cells
4) water conducting cells
5) food conducting cells
193
Define parenchymal cells
Most abundant cell type
Have only primary cell walls which are thin and flexible
Preform most metabolic plant function
-photosynthesis
-aerobic respiration
-food storage
-most can divide and differentiate into other types of plant cells
194
Define collenchyma cells
Do not have secondary cell walls
Usually have thicken primary cell walls
Provide flexible support in parts of the plant that are still growing
Young stems and petioles often have collenchyma cells just below their surface
These cells remain alive and elongate as stems and leaves grow
195
Define sclerenchyma cells
Have thick secondary cell walls
Strengthened with the lignin
Mature cells cannot elongate and thus are found in regions of the plant that have stopped growing
Most are dead at maturity
These cells form a rigid cell skeleton to support the plant
196
There are two types of sclerenchyma cells what are they
Fibers - long and slender and often arranged in bundles
Sclereids - shorter then fibre cells have thick irregular and very hard secondary walls
Cells responsible for the hardness of nutshells
197
Describe water conducting cells
Have rigid lignin containing secondary cell walls
Chains come from tubes by overlapping their end
Carries water from the roots to the stems and leaves as part of the xylem tissue
These tubes are hollow and the cells dead when they are mature and only their cell walls remain
Rigid thick walls allow these cells to function in support
198
What are the two types of water conducting cells
Tracheids -long thin cells with tapered ends
Vessel elements - wider shorter and less tapered
199
Describe food conducting cells
Sieve-tube members are arranged end to end like xylem forming tubes
Remain alive at maturity but loose most organelles (nucleus and ribosomes)
Allows more room for the transport materials
End walls have sieve plates containing pores that allow fluid to flow from cell to cell
200
Describe companion cells in food conducting cells
Alongside each sieve tube cell (at least one) connected by plasmodesmata and function to supply the cell with proteins
201
Define primary growth of plants
Lengthens roots and shoots
202
Most plant species experience ____ meaning that they continue to grow for the duration of their life
Indeterminate growth
203
Most animals experience ___ meaning that they cease growing after a certain length
Determinate growth
204
Angiosperms are characterized according to life cycle duration what are the three types
1) annuals - complete lifecycle in one year or less (crops)
2) biennials - complete lifecycle in two years (beers/carrots)
3) perennials - live and reproduce for many years (trees shrubs ext)
205
Do plants die from old age?
No they die from environmental factors
206
Plant growth is made possible by tissues called____
Meristems
207
Define meristems
Consist of cells that divide frequently generating more cells
Some of these new cells remain in the meristem and continue to divide while others differentiate being incorporated into the tissues of the growing plant
208
Define apical meristems
Located at the tips of roots and the buds of shoots
Cell division Helps produce new cells allowing the plant to grow in length called primary growth
Enables roots to push through the soil and shoots to increase exposure to light and CO2
Roots and shoots lengthen using different mechanisms
209
Explain root growth
The tip of the root is covered by a root cap which protects the cells of the apical meristem which are actively dividing
210
Growth in length occurs just behind the root tip with three areas of distinct cells which are..
1) the zone of cell division
2) the zone of elongation
3) the zone of maturation
(No sharpe boundaries between these three areas)
211
Explain the zone of cell division
Contain the cells of the root apical meristem and cells that derive from it
New cells of the root are produced here including root cap cells
212
Explain the zone of elongation
Root cells here elongate (as much as ten times their original length)
Pushes the root tip further into the soil
Cells lengthen and do not expand because of cellulose fibre arrangement
Cells take up water and the cellulose fibres separate expanding like an accordion
213
Explain the zone of differentiation
All three plant tissues complete their development here
(Dermal ground and vascular tissues)
Cells in the vascular cylinder differentiate into primary xylem and primary phloem
Differentiation occurs because of differential gene expression
214
Define secondary growth of plants
Woody plants continue to grow in the girth once primary growth is complete
Occurs because of activity in dividing lateral meristems that are arranged into cylinders called vascular cambium and cork cambium
215
Define lateral meristems and how are they arranged
Where cells divide to cause secondary growth
| Arranged into cylinders called vascular cambium and cork cambium
216
Define vascular cambium
Cylinder of meristem cells one cell thick between the primary xylem and primary phloem
217
Secondary growth adds layers of vascular tissue on either side of the ____
Vascular cambium
218
The vascular cambium gives rise to two new tissues that are ..
```
Secondary xylem
(the interior of the vascular cambium)
```
Secondary phloem
(The exterior of the vascular cambium
219
Secondary xylem composes _____
The wood of the tree cell walls are rich in lignin providing characteristic wood strength
220
When secondary growth begins the epidermis sloughs off and is replaced by ____
Cork (the new outer layer)
221
Describe cork
Mature cork cells are dead and have thick waxy cell walls that protect the under layers
222
Cork is produced by what
The cork cambium which first forms from parenchymal cells within the cortex
223
Everything outside the vascular cambium is called ___
Bark
Main components are secondary phloem cork cambium an cork
Youngest secondary phloem functions in sugar transport and older secondary phloem dies
224
When no cortex remains it forms from ____
Parenchymal cells in the phloem
225
The bulk of the tree is ____
Dead tissue
226
What does the living tissue of the tree consist of
Vascular cambium
Youngest secondary phloem
Cork cambium
And cells in the wood rays
227
Define wood rays
Consist of parenchymal cells that transport water and nutrients
They also function in nutrient storage
228
Define heartwood
```
Trunk cells
Older secondary xylem
No water transport
Clogged with resin
Will not rot
```
229
Define sapwood
Younger secondary xylem
| Conducts xylem sap
230
Fertilization of flowering (angiosperms)
Diploid plant body is the sporophyte
The sporophyte produces specialized structures which cells undergo meiosis in order to become a multicellular gametophyte
231
Sporophyte in angiosperms produces what type of specialized reproductive structures
Anthers
| Ovules
232
The gametophyte of angiosperms is the plants _____ generation which produces ______ by _____
Haploid
Gametes
Meiosis
233
Spores in the ___ give rise to the ___ gametophytes which are ____
Anthers
Male
Pollen grains that produce sperm
234
A spore within an ovule produces the ____ which is the ____ gametophyte containing an _____
Embryo sac
Female
Egg cell
235
Pollination of angiosperms is ___
The arrival of pollen grains into a stigma
236
A pollen tube grows into the ovule and sperm passes through it fertilizing both the egg and a second cell called ____
Double fertilization
237
The ovule develops into a seed and is now a ____ and its nucleus divides by mitosis and produces ____
Triploid (3n)
| Endosperm
238
The zygote divides by mitosis producing the embryo and the ovule looses most of its water and develops a _____ enclosing the endosperm and the embryo
Resistant seed coat
239
The seed may remain dormant and only begin to grow when ____
Favourable environmental conditions occur (seed dormancy)
240
Describe eudicots seeds
Two cotyledons
Apical meristems lack protective sheaths
Endosperm is absorbed by the cotyledons
241
Describe monocot seeds
Single cotyledon
Apical meristems have a protective sheath
Endosperm is present
242
Hormonal changes which Occur as a result of fertilization trigger the ovary to develop into a ___
Fruit
243
The fruit functions to ___
Protect the seed and to aid in dispersal
Mature fruits may either be fleshy or dry
Fleshy fruits= oranges
Dry fruits= beans
244
Seedling germination occurs when...
When a seed absorbs water
The seed begins to expand as a result of water absorption causing the seed coat to rupture
The embryo now begins to grow and produce enzymes
The enzymes function to digest the endosperm releasing nutrients that can be used as energy
245
Define vegetative reproduction
Asexual reproduction
Involved fragmentation of the plant body
Each fragment gives rise to a genetically identical daughter plant
Ie) garlic
246
Explain plant importance
Provides shelter for animals fungi and bacteria
Provides food for animals
Roots function to prevent erosion of soil
Photosynthesis reduced atmospheric CO2 and provides the atmosphere with o2
Plants benefit humans immensely
-lumber paper food industrial chemicals ext
247
Explain how plants acquire nutrients from soil and air
Plant roots absorb water minerals and oxygen from the soil
Leaves take CO2 from the air
Photosynthesis uses water CO2 and minerals to produce sugars composed of carbon oxygen and hydrogen
Inorganic ions such as nitrogen and magnesium are components of photosynthetic pigments
Inorganic ion phosphorus is a major component of DNA and RNA as well as ATP and phospholipids
248
Describe plants control of solute uptake
The absorptive surface area of the root is dramatically increased by the presence of root hairs
Water and solutes must first enter the xylem before they can be transported up the plant body
To enter the xylem the water may either move through cells (intracellular route) to move through the epidermis and the cortex
Or it may move between the cells (extracellular route)
249
Explain the intracellular pathway of solute uptake
Moves through the cell membrane of a root hair
Through the plasmodesmata then through the cytoplasmic content of the cortex cells and endodermal cells finally into the xylem vessels
250
Explain the extracellular pathway of solute uptake
Moves through the cell wall of all epidermal and cortex cells and within intracellular spaces
The waxy barrier called the Casparian strip in the walls of the endodermal cells forces the water through the endodermis and into the xylem
251
Describe transpiration
Pulls water up the xylem vessels
Root pressure can only push the xylem sap up a few meters
Solute transport raises the water pressure in the xylem
The xylem sap is pulled upward from the soil through a transpiration cohesion tension mechanism
252
Define xylem sap
Inorganic nutrient solution that travels up xylem from a plants roots and shoots
253
Define transpiration
Loss of water from the leaf
Exerts a pull on xylem sap
Cohesion causes the water molecules to adhere to one another
Relays the pull of transpiration along a string of water molecule all the way to the roots
The adhesion of water molecules to the exterior of the xylem cells aids to combat the force of gravity
254
Explain guard cells
Surround the stoma and control the opening thus controlling transpiration
As the guard cells open the stomata they actively pump potassium in increasing the solute concentration within the cell
Water follows the solutes because of osmosis
When the stomata looses K the guard cells close
255
What are the 3 cues for the stomata opening
1) increased sunlight cause the guard cells to take up K if water is lost too fast the guard cells close
2) decreased internal CO2 has the same effect as increase sunlight
3) an internal daily timing mechanism triggers K uptake and stomata opening in the morning and stomata closing in the evening
256
Describe the phloem
Transports sugars made by photosynthesis via a pressure flow mechanism
257
Explain the phloems pressure flow mechanism
1) sugar is loaded into phloem tube at the source which raised the solute concentration within the tube
2) water is the drawn into the tube by osmosis raising the tube pressure
3) sugar and water leave the tube at the sugar sink
(The increase in pressure at the sugar source and decrease in the pressure at the sugar sink causes the sap within the phloem to move from source to sink
258
Describe fertilizers
Help to prevent nutrient deficiencies
The availability of nutrients within the soil affect plant growth and health
The absence of certain nutrients lead t particular plant symptoms which can be identified
The addition of inorganic fertilizer or compose to soil can alleviate these deficiencies
Stunting of growth wilting of the plant and changes in the colour all indicate nutrient deficiencies
259
Describe nitrogen deficiencies
Most common
Stunted growth and yellow/green leaves
Affects the older leaves first
260
Describe phosphorus deficiencies
Second most common
Sometimes purplish leaf colour
Reduced growth rate
Spindly and brittle new growth
261
Describe potassium deficiencies
Yellow leaves with brown margin
Localized symptoms
Stunted growth
