Plants... Fucking Plants... Flashcards
1
Q
What are plants?
A
Plants are:
- Autotrophic organisms which are able to synthesize all required organic compounds from inorganic substances using sunlight as an energy source.
- Multicelled and Eukaryotic
- Evolved from green aquatic algae about 500 million years ago
- Over a quarter million plant species are known today and are found in many diverse regions, from desert areas to polar areas.
- Have cell walls made of cellulose (Beta-glucose linkage)
2
Q
When is a plant vascular?
A
Vascular plants contain distinctive areas of specialized tissue called xylem and phloem
3
Q
What is Xylem?
A
Xylem is the vascular tissue in plants that conducts water and minerals from roots to the rest of the plant in one direction
- Contains cells called tracheids, thus are called tracheophytes
- Contains cells called a vessel member
- Both Vessel Member and Tracheid cells are dead at maturity
- Xylem also aids in supporting the plant and is what makes up the woody part of the stem or tree trunk
- Xylem can only transport upwards.
4
Q
What is Phloem?
A
Phloem is the vascular tissue in plants that carries sugar from the leaves to the rest of the plant.
- Phloem can transport things both upwards and downwards as needed.
- The main conducting cells are called sieve-tube members. Sugars made by photosynthetic leaves are loaded into these tube members with the help of companion cells. Sugars are then unloaded for growth or storage
5
Q
What is a cuticle?
A
A cuticle is a hydrophobic waxy coating that surrounds the leaf and prevents it from losing water
6
Q
What is transpiration?
A
Transpiration is water evaporation in plants
7
Q
How does CO2 enter the plant?
A
Co2 enters the plant through special openings in the leaf called stomata.
- Stomata allow the Co2 to diffuse through into the leaf.
- CO2 must combine with water before it is allowed to be absorbed by leaf cells
8
Q
What are stomata?
A
Stomata are openings in the leaf that allow water to evaporate and allow CO2 to come into the leaf.
- In most plants, stomata stay open during the day when photosynthesis can occur. This results in a loss of water and an uptake of CO2 into the cell
- At night stomata are usually closed. This leads to the conservation of water and CO2 accumulation.
- Stomata are opened up by guard cells.
9
Q
What are guard cells?
A
Guard cells open and close stomata based on water content in the plant.
- When the plant is full of water, guard cells swell up opening up the stomata.
10
Q
Why is transpiration of water in plants important?
A
Xylem pull water and nutrients up the roots and into the rest of the plant.
- The only way it can do this is if there is a negative osmotic pressure up top that pushed the water upward.
- The plant must lose water through transpiration in order to create that negative pressure.
11
Q
What determines if a soil is suitable for plant growth?
A
Aeration and H20 capacity will determine if the soil is suited for plant growth.
12
Q
What are roots?
A
Roots are specialized plant structures:
- grow downward
- Absorbs H20 and minerals
- Anchors the plants
- Stores food and releases it as needed
- All begin with a single root (primary root), but then grow differently into smaller roots (secondary roots)
- Root surface area is increased enormously by outgrowths called root hairs.
13
Q
What is the meristem?
A
The meristem is the root tip
- This is an area of active cell division. We see new plants grow and older plants lengthen
14
Q
What are the structures of the root?
A
A root contains:
- Epidermis
- Cortex
- Endodermis
- Stele
- Nodules (in N2 fixing plants)
15
Q
What is a roots Epidermis?
A
The roots epidermis is the outermost layer of the root which includes the root hairs.
16
Q
What is a root’s cortex?
A
A root’s cortex stores starch and contains parenchymal cells
17
Q
What is a root’s Endodermis?
A
A root’s endodermis is the innermost layer of the cortex
- its associated with a waxy tissue band called a Casparian strip
- This strip is involved with controlling the uptake of water and dissolved nutrients
18
Q
What is the root’s stele?
A
The root’s stele:
- Layer of cells inside the epidermis containing xylem and phloem cells.
- This is also called the vascular cylinder.
- Cambium tissue lies between the xylem and phloem, and will add more layers of xylem and phloem to thereby thicken the root
- The outer part of the stele is a layer of cells called a pericycle. These cells can initiate the development of secondary roots.
19
Q
What are root nodules?
A
Root nodules:
- On the roots of legumes such as peas and beans, we see swellings called root nodules that contain nitrogen-fixing bacteria which convert atmospheric N2 into forms required by the plant, such as NO3- and NH4+
20
Q
Why do plants need to absorb NH4+ and NO3-?
A
Plants use NH4+ and NO3- to form amino acids, proteins, and other nitrogenous compounds?
21
Q
How do plants get the NH4+ and NO3- they need?
A
Plants get their nitrogen either through:
- root nodules: Use bacteria in the nodules to fix Nitrogen in the air into forms required by the plant. NH4+ and NO3-
- Nitrification: Bacteria in the soil break down dead organisms to release NH4+. The NH4+ is then oxidized into NO3-. These are both brought up into the plant through the root.
22
Q
What is nitrification?
A
Nitrification is the process in which bacteria break down dead organisms in the soil to release NH4+, that is later oxidized into NO3-.
23
Q
What is denitrification?
A
Denitrification is the process by which the plant uses the NH4+ and NO3- taken up by the soil and converts it into N2 and a small amount of N2O
24
Q
What is the nitrogen cycle?
A
The nitrogen cycle is the process by which plants use nitrogenous molecules from the soil and then produce N2 gas.
25
What is mycorrhizhae?
Mycorrhizae is the association of a nonpathogenic fungi with roots
- Materials absorbed by the roots passes first through the fungi which allow them to gain nutrients
- The fungus increases the surface area available for water and nutrient uptake. Some trees grow very poorly without this fungus.
- Orchids also depend on this symbiotic relationship called mutualism
26
What is dermal tissue?
Dermal tissue covers the plant and provides it protection
- Cuticle: Waxy layer that prevents evaporation of water from the plant
- Epidermis: layer of tightly packed cells that covers the primary plant body. It is only a single cell large and many epidermal cells have extensions as root hairs.
27
What is ground tissue?
Ground tissue is the third plant tissue type besides vascular and dermal tissue it is composed of:
- Parenchyma cells
- Collenchyma cells
- Sclerenchyma cells
28
What are parenchyma cells?
Parenchyma cells are a type of ground tissue:
- Most abundant ground tissue
- Thin walls seen in roots, stems, and leaves
- Storage, secretion, and photosynthesis involvement
29
What are collenchyma cells?
Collenchyma cells are a type of ground tissue:
| - Cell walls are thick and provide flexible support for the growing stem
30
What are sclerenchyma cells?
Sclerenchyma cells are a type of ground tissue:
- Very thick cell walls that provide protection and support
- contain lignin, this is the second most abundant polymer in the world second only to cellulose.
- Lignin and cellulose both work together to provide strength and support
- Lignin also forms a barrier against invaders like fungi or insects
31
What is lignin?
Lignin is a polymer created by sclerenchyma cells
- It works with cellulose to provide support and strength to the plant.
- It also forms a barrier against foreign invaders like fungi or insects
32
What are stems?
Stems are part of the shoot system that is composed of stems and leaves
- support shoot system structure
- Transport substances between roots and the leaves
- Store food (some carry our photosynthesis. In a cactus, this is where the main photosynthesis reaction occurs)
33
What structures of the plant contain the three tissue types of the plant?
The roots, stems, and leaves of plants contain all three tissue types:
- Dermal
- Ground
- Vascular
34
What are angiosperms?
Angiosperms are the most abundant plant type on earth (90%)
- Flowering plants, fruits, oaks, maples, grasses
- Most diverse plants
- Produce seeds
- As seeds develop from structures called ovules after fertilization, the ovary becomes the fruit.
- Seeds contain a cotyledon: an embryonic leaf
35
What are the two categories of angiosperms?
The two categories of angiosperms are:
- Monocots
- Dicots
36
What is a Monocot?
A monocot is one of the two categories of angiosperms
- Has a single cotyledon
- Long narrow leaf with parallel veins
- Vascular bundles scattered
- Floral parts in multiples of three
- Cambium absent
37
What is a Dicot?
A dicot is one of the two categories of angiosperms
- Has two cotyledon
- Has a broad leaf with a network of veins
- Vascular bundles in a ring
- Floral parts in multiples of 4 or 5
- Cambium present
38
What is a cotyledon?
A cotyledon is an embryonic leaf in a seed.
- This is the main differentiator in the name dicot vs monocot
- This is the first leaf produced by the plant and is ultimately replaced by a different leaf type after sprouting has occurred.
39
What is the stamen of the angiosperm (flower)?
The stamen includes the male reproductive parts of a flower. These include:
- Anther: Chamber where pollen grains develop on top of the filament
- Filament: A slender stalk with the anther as its head
40
What is the anther of an angiosperm (flower)?
The anther is a part of the stamen where pollen grains develop
- It sits on top of the filament like a head
41
What is the filament of the angiosperm (flower)?
The filament is a part of the stamen of the flower.
| - It is a long slender stalk that lifts up the anther like a head.
42
What is the carpel of the angiosperm (flower)?
The carpel is the female reproductive part of the flower. It includes:
- Ovary: eggs (ovules) develop, fertilization occurs, and seeds mature
- Style: a connecting stalk
- Stigma: Sticky part that catches the pollen
The stigma sits on top of the style and catches the pollen. The pollen is transported down the style into the ovary, via the pollen tube, where the ovules are fertilized and seed formation occurs
43
What is the ovary of an angiosperm (flower)?
The ovary of an angiosperm is located in the carpel of the flower.
- It contains ovules that will be fertilized by pollen.
44
What is the style of an angiosperm (flower)?
The style of an angiosperm is located in the carpel of the flower.
- It connects the stigma with the ovary, providing a route for the transportation of pollen from the stigma to the ovary via the pollen tube.
45
What is the stigma of an angiosperm (flower)?
The stigma of an angiosperm is located in the carpel of the flower
- It is a sticky structure that captures pollen. Once captured the pollen tube elongates and carries the sperm through the style and into the ovary, where the ovules are fertilized and become seeds.
46
What is the petal of an angiosperm (flower)?
The petal of a flower is a projection away from the sex organs of the plant that is usually colored in pigment
- It helps attract pollinators
47
What is the sepal of an angiosperm (flower)?
The sepal of a flower offers protection at the base of the flower.
- Collectively the sepals are called the calyx
- After flowering, the calyx will wither away
- This is the green bit that protects the budding flower.
48
Describe pollination
Pollination occurs when pollen reaches the stigma.
- The pollen grain develops into a pollen tube which grows toward the ovary and contains two sperm cells
- One sperm fuses with the egg and a (2N) zygote is made
- The other sperm fuses with two polar nuclei cells to make a 3N cell. This will give rise to nutritive tissue as the endosperm
- The ovule (egg) becomes the seed and the ovary becomes the fruit.
- Seeds are multicelled and protect the embryo inside.
49
What are the three unique features of angiosperms?
The three unique characteristics of angiosperms are:
- Flowers
- Fruits
- Double Fertilization
50
What is a gymnosperm?
A gymnosperm is a plant with a naked seed
- They were the first seeding plants
- Non-flowering plants
- Seeds not enclosed in a chamber like angiosperms, but exposed on modified leaves that become cones
- include conifers (fir, pine, cedar, and spruce)
- include the tropical and subtropical plants called cyads
- Fertilization is similar to angiosperms, except there is no double fertilization
51
How does fertilization occur in gymnosperms
Fertilization in Gymnosperms happens in the following way:
- Pollen is shed from the pollen cone and reaches the female gametophyte in the female cone.
- The pollen is carried to the eggs through pollen tubes
- Male gametophyte (pollen) fuses with the egg to form a zygote
- The zygote -> embryo and ovule -> seed
52
What are Microspores?
Microspores develop into male gametophytes which give rise to sperm cells
- in Angiosperms these develop in the anther
- In Gymnosperms these develop in pollen cone
53
What are Megaspores?
Megaspores develop in the ovule into female gametophytes
| - Found in Gymnosperms and Angiosperms
54
What are the types of pollination among both gymnosperms and angiosperms?
The two types of pollination are:
- Self-pollination: Pollen grains are transferred from itself to the ovule of itself
- Cross-pollination: Pollen grains are transferred from itself to another plants ovule
55
Does cross pollination occur more in angiosperms or gymnosperms?
Cross-pollination occurs more in angiosperms, because the colorful flowers they have attract pollinators like bees, butterflies, etc to help spread their pollen.
- This leads to more genetic variety in angiosperms vs gymnosperms.
56
What are dioecious species?
Dioecious species are plants that are distinctly male or distinctly female
- Staminate flowers: Only contain the stamen or male reproductive parts
- Carpellate flowers: Only contain the carpel or female reproductive parts
- Helps promote genetic variability. Only cross-pollination can occur.
57
How can plants reproduce asexually?
If a cutting is taken from a plant and given the proper conditions, it can become its own plant.
- This is a clone of the the parent plant
58
What is grafting?
Grafting is taking plants of different types and growing them together.
- This can lead to a plant with different characteristics, some beneficial or malignant
59
What is the alternation of generations?
In all land plants, alternation of generations is observed
- In plants, meiosis does not directly produce gametes
- In plants meiosis gives rise to spores which are haploid.
- Spores do not undergo fertilization, instead they divide through mitosis to become a multicellular haploid plant called a gametophyte.
- Eventually this spore-derived haploid plant produces the gametes.
- The gametes are fertilized together and form a diploid sporophyte
- The alternating formation of a gametophyte and sporophyte (two distinct plant types) is called the alternation of generations.
In angiosperms, the spore (gametophyte) is the ovule or pollen. These are multicellular and divide via mitosis to produce the gamete. These live on the sporophyte.
60
What are Bryophytes?
Bryophytes are Non-vascular plants
- Oldest of all lands plants
- lack xylem and phloem tissue
- Moss (most common), liverworts, and hornworts
- Have waxy cuticles to control H20 loss
- Relatively small
- Live in moist places
- Can be found in Antarctica and eve deserts
- Anchored to the ground by rhizoids (root like absorptive structures)
- Very sensitive to air pollution
- May have evolved from green algae
61
Describe the sexual process for bryophytes
Bryophytes life cycles are dominated by gametophytes (unlike vascular land plants)
- They need water for the sperm to reach the egg
- Gametes are made in multicellular organs called gametangia
- Two types of gametangia
* Archegonia: Female gametangia - produces an egg
* Antheridia: Male gametangia - produces sperm
- The sperm is flagellated and swim to the egg.
- Fertilization occurs in the archegonia, where the zygote develops into an embryo
- No seed is created
62
What is a gametangia?
Gametangia is a multicellular organ in a bryophyte that produces gametes.
- The female organ is called a archegonia
- The male organ is called an antheridia
63
What is an archegonia?
An archegonia is the female gametangia of a bryophyte
| - Eggs are produced here.
64
What is an antheridia?
An antheridia is the male gametangia of the bryophyte
- Sperm is produced here.
- Sperm is released in wet conditions and is flagellated to use water to swim to the archegonia to fertilize an egg
65
What is the dominant life cycle form of:
- Angiosperms
- Gymnosperms
- Bryophytes
- Ferns
The dominant life cycle forms are the following:
- Angiosperms: Sporophyte (gametophytes are protected inside the plant)
- Gymnosperms: Sporophyte
- Bryophyte: Gametophyte
- Ferns: Sporophytes
66
What are ferns?
Ferns are seedless flowerless vascular plants
- Leaves are called fronds
- Sori are found on the lower surface of many fern fronds. These are sporangia (contains the spores) clusters that are yellow or rust-colored. Like a catapult, they can open and snap shut allowing spores into the air
- The evolution of vascular tissue allows them to grow taller than bryophytes
- The sporophyte dominates in the fern life cycle. Meiosis will be done in the sporangia, which makes the haploid spores
- Once again, alternation of generations occurs
- Ferns use spores rather than seeds to to reproduce
67
What types of plants reproduce with spores instead of seeds?
Ferns and Bryophytes reproduce with spores instead of seeds
68
What are auxins in plants?
Auxins are a plant hormone that:
- Promotes stem elongation and fruit development and prevents premature fruit drop
- Some synthetic auxins are used in herbacides
- Apical meristems and leaves show most abundance of auxins
69
What are meristems?
Meristems are cells that reside at the shoot and root tips of plants.
- They are undifferentiated cells that can differentiate into whatever they plant needs
- Think roots or stems. Like when I propagate basil. The nodes can shoot out stems in the air, or roots in the water.
70
What are cytokines in plants?
Cytokines are a plant hormone that:
- Stimulate cell division
- Delays leaf aging
- Abundant in roots
71
What are gibberellins in plants?
Gibberellins in plants
- Like the auxins, promote stem elongation, pollen development, fruit development
- Works with the auxins and are involved with the flowering process
72
What is abscisic acid in plants?
Abscisic acid is a hormone in plants:
- Inhibits plant growth
- Inhibits seeds from germinating
- Causes stomates to close during times of drought
73
What is Ethylene?
Ethylene is a plant hormone:
- Gas that stimulates green fruit into ripening
- Found in fruits, plants, seeds, leaves, and even roots
- Used to artificially increase aging in picked unripened fruit
- Triggers the release of abscisic acid
74
What is a tropism?
A tropism is a growth response to an environmental factor
75
What is gravitropism?
Gravitropism is a direction growth in response to gravity
76
What is phototropism?
Phototropism is a direction growth in response to light
77
What is thigmatropism?
Thigmatropism is a growth in response to physical contact
| - Vines that attach to things like a trellis
78
How do plants respond to light and dark?
Plants have a circadian rhythm just like animals
| - Stomata close during the night to preserve water and open during the day to let in CO2
79
What is photoperiodism?
Photoperiodism is a biological response to a change in daylight length and darkness in a 24-hour day
- The main basis is a blue-green pigment called phytochrome, which mostly absorbs red light. This acts as a switching mechanism which can control the activation and inactivation of plant hormones
- This allows the plant to start inhibiting growth in low light cold environments
