plant: structures and functions (lesson 9a)

Question 1

What is sucession and what is primary sucession? What is secondary sucession?

Answer 1

Sucession: a gradual chance in the composition of a community over time (in reference to plants) or species that forms a commnunity overtime
—> Biodiversity continues to increase at each stage as abiotic and biotic factors change

Primary sucession: sucession in an area that had no plants, animals or soil, becomes colonized by an organism.
–> An organism colonizes a bare surface, and this change is the first change this surface experienced.
(From nothing to something [ie a forest] gradually)

Seconary sucession: (There was something there, then that ecosystem was distruibed by humans/a natural disaster (therefore becoming bare again) and now theres a second wave of growth).
–> Sucession that occurs after a destructive interactions by humans/natural disaster.
—-> Nothing, something, nothing, something.

Question 2

What do plants need to survive?

(methods of gaining energy? [specific?])

Answer 2

Require: Carbon dioxide, water, and sunlight for photosynthesis.
—> Inturn produces gluclose and oxygen (Which is required for cellular respiration) (A produc needed for mitrocondria, which plants ALSO have)

They also require other gasses for protein and lipid synthesis

Because they do photosynethsis,
They are autotrophic: specifically photoautotrophs, because they conduct photosynthetsis.

Question 3

How do plants defend themselves?

Answer 3

Needles, thorns, bark

Question 4

What are the 2 organ systems for plants

Answer 4

ALL PLANTS HAVE:
Root system: All of the material below the ground, including the roots, root hair, root tips.
(NOTE: not all roots are above ground, some plants have exceptions)

SHOOT SYSTEM: All of the material above ground, including the structures: stems, leaves, flowers, etc
(NOTE: not all stems and leaves are above ground, some plants have exceptions)

Exceptions:
Epiphytes are plants that grow on other plants or objects for physical support. They are NOT parasitic, therefore they only use the plant as a physical anchor. they grow entriely above ground.
—> “air plants”
-> Their roots anchor onto other plants.

Question 5

The cell wall of plants is made of?

Answer 5

Cellulose

Question 6

What are the 4 majour organs of most plants?

Answer 6

Roots

Stems

Leaves

Flowers: (angiosperms specifically)
–> A plants reproductive organ can also be gymnosperms (cones) or spores (non-vascular pants and lycophytes or pterophytes)
Reproductive organ

Question 7

What are the 4 types of stem tissues (and what are they breifly about/overview?)

Answer 7

Dermal: Outerskin

Vascular: Xylem/phloem

Ground: All the tissues that are not dermal or vascular, they are the “middle” tissues

Meristematic: Stem cells (Cells that are undifferentiated cells, and that can turn into anything)

Question 8

What is the dermal tissue?

Answer 8

Outer most layer: Protection
—> The dermal tissue cells, have thicker cell walls, and are covered in a waxy cutical (why?)
-to protect agaunst injury,
-herbivores,
-disease,
-and water loss and prevent water loss

–> Dermal tissues containstomata, which is crutial for gas exchange and guard cells which control the stomata.

Question 9

What are the vascular tissues?

Answer 9

Transportation of water and nutrients.

FUNCTION AND DIRECTION OF FLOW:
Xylem: transports nutrients and water (How does it transports nutrients, these nutrients are within the water).
—> Moves from the roots to the shoots **(1 way system) ** (roots –> stems –> leaves)
Phloem: Transports organic nutrients (gluclose, sugars) from source to sink.
–> **Bidirectional, because the SOURCE and sink CHANGES depending on the season. **
—> Summer = source is leaves
—> Winter = source is roots

STRUCTURE:
Xylem: Thicked walled cells, Dead cells (Supported by lignin)
—> Thick cell walls = provides structure and strength to the plant

Phloem:
Thin-walled cells, cells are living.
–> Has sieve plates which are pores and sieve tube elements.
Has sink and source cells

METHOD OF TRANSPORTATION:
Xylem: passive transportation via osmosis to pull the water from the roots to the leaves.
**Nutrients enter by active transport. **
—> Ongoing cycle, because nutrients are solutes, and make the water concentration low, which is why water moves up. (When the nutrients moves, distrupts equilbirum, causing water to “move” to make itself equal)

(high –> low, till equillibrum)

Phloem: Uses translocation (changing location): Long distance transport of substances (gluclose)
Source (high concentrations of sugars and solutes) –> Sink (low concentration)

Moves through diffusion gradient and osmosis.

Question 10

What are meristematic tissue?

Answer 10

Meristem: area of growth. rapid cellular division of UNDIFFERENTIATED CELLS.
—> Cells specialize into different tissue types later on, and new roots and shoorts are formed via mitosis (the method of reproduction these cells use to quickly duplicate and divide themselves)

—> Most are at the “buds”

Question 11

What is ground tissue? (Breif details)

Answer 11

3 types of tissues, all different, 2 are living 1 is dead.

includes all tissues that are neither dermal nor vascular.

Question 12

What are leaves? (Importance + function)

Answer 12

Site of photosynethesis and gas exchange, containing chloroplast (an organelle where photosysthetsis occurs), and chlororplast contains chlorophyll, responsible for the green pigment)

Why is photosynethsis important?
–> makes gluclose which is needed for cellular respiration and building tissues

Note: Chloroplast does not always hold chlororphyll. Plants will still have chlorophyll even if it is not contained in the chloroplast.

Question 13

What are the 3 different structures of the leaf?

Answer 13

blade: flat part (large, very visible)

Petiole: the stalk that connects the leaf to the stem (NOT THE STEM, but connects the blade to the stem) (looks like the stem on the blade)

Viens: the vasuclar system for transporting the nutrients and the water

Question 14

The structure of the leaf: Diagram

Answer 14

Cutical, upper epidermal tissue (“skin layer), palisade meophyll (where there are many chloroplasts), vasuclar tissues (xylem; water, phloem, sugars) which is encompassed in the spongy meophyll, lower epidermal tissue (skin), (within the lower epidermal tissue there are) stomata and guard cells!

Question 15

Structure: Stem, whats the importance?

What are the two types of stems?

Answer 15

The stem provides a tube for the vascular tissues .
—> step supports the leaf and the reproductive organs (ie flowers)
—> Some plants can store water or carbohydrates in the stems (ie: cactuses)

Two types of stems:
Herbaceous plants: stems that do not contain wood (ie tomato plants, dandilions)

Woody plants:
(Stems that contain wood)
—> Ie: all gymnosperms. (plants that reproduce using cones)
–> Started as a normal stem, and slowly prohessed into wood.

Question 16

Primary growth of herbaceous and woody stems?

Answer 16

Vertical growth, the increase in length of roots and shoots (both systems) (increase from the bottom, going lower, or growing taller)

Question 17

Secondary growth of plants?

Answer 17

-> Only in reference to woody stems, there herbaceous plants do not experience Stem thickness (/very very minmal stem thickness)

—> Secondary growth refers to increased stem thickness/ side ways growth.
Occurs throughout the plants lifetime, typically after the primary growth has establish the basic structure of a plant.

–> Where?
Vascular cambium (a meristematic cells layer) that creates new xylem and phloem layers that surround the stem and it gradually grows
—> Creates the “wood”
–> In trees you, when cut you can see the “rings’ these rings are old xylems.
–> Creation of heartwood: old xylem (the non-living part of a tree that provides structural support)
–> filled of resins and oils

Question 18

Human interferance/modified stems? (2)

Answer 18

1) Under ground stems (ie: carrots and potatos) (SCIENTIFIC name:** tubers**)
–> Stores foot and water underground.

2) Above ground stems
—> Ie (Stolons) of spider plants **grow along soil instead of upright **
(SImilar to strawberries)
–> Ie: grape vines
(Many different types of above ground stems)

Question 19

What are roots and what are the 2 types of roots?

Answer 19

Roots: helps anchor plants to the ground, and use the soil to absorb water and nutrients.
Stores carbohydraes made by photosynethsis (turning into a source, in the winter)

1) Taproot system: a large thick root, that has smaller lateral roots branching from it. (1 main root)
–> The main root is not always very big, but is larger than the smaller ones.

2)Fibourous roots, many small branching roots (no main root, all roots are relatively the same size)

Question 20

What supports the roots? / “Root speicialization” (What helps the roots)

Answer 20

Roots have a mutalistic (+/+) relationship with mycorrhizal fungi.

–> Fungi decomposes organic matter (providing plants with nutrients), while the hypae of of the fungi help increase water and nutrient intake to plants, because of how extensive it is (longer than the plants roots), fungi also help protect plants from diseases.

–> Fungi recreive nutrients and carbohydrates produce by the plants through photosynthesis.

Plants have a mutalism relationship with nitroggen-fixing bacteria:
Bacteria live in the nodules (small, swelling areas on the roots of plants, most notabel legumes [beans, peas, etc]) in plant root.
–> Nitrogen fixing bacteria converts atmospheric nitrogen (which plants cannot directly use) into forms of nitrogen that plants can absorb and use for growth), while the bacteria gets carbohydrates in return.

Question 21

Plant growth, do plants all grow at the same time? How do plants grow?

Answer 21

Plants do not all grow at the same time.

Plants have photoreceptors which are specialized proteins that detect the wavelength of light within the plant (What light is hitting the plant)
–> When detected, controls the plants growth and response to day length

–> Photoperiodism the physiological/deveolpemental reaction to the changing length of day. where some plants bloom during the short days, some plants bloom during long days.
–> The deveolpemental response of plants to the length of day

–> Different types of flowers, ie short day plants (blood when sunlight is shorter/the days are shorter), long day plants, and day nutreual plants (regardless of day length, there will be a flower)

Different plants bloom during different day lengths

Question 22

How does temperature affect the growth of a plant?
—> How does it affect the plant in general
–> Germination
—> Flowering
–> Climate change
–> Stomata

Answer 22

In general:
Opening and closing of stomata affected by temperature - (More stomata open/closed)
—> Depending on reasoning can controdict itself.
Hot = more photosynthesis because theres more light out (Some people may say less photosynethesis because plant is tryig to prevent water loss)
——> Stomata: 2 roles, waterloss and gas exchange for photosynthesis

Germination of seeds (hotter = faster chemical reactions, easier for seeds to germinate)

**Flowering of angiosperms **(More light = more flowering, longer days in the summer)

Climate change is altering flowering periods of many species -** Increases competition for pollinators (can cause more plants to bloom in the same time, which can increase competetions for the bees to pollenate them)**

Question 23

How can soil affect the growth of a plant?

Answer 23

Soil should contain humus (organic matter),

Optimal soil:
Should not be too sandy (not enough water) or clay-filled (too much water)

Soil should be mildly acidic for optimal nutrient uptake

Question 24

What is tropism?

Answer 24

directional change in growth or movement in response to a stimulus

–> If something makes the plant grow better, the plant will try to grow towards it/change itself to optimally intake this stimulant

Question 25

What are the 3 different types of tropisms?

Answer 25

Phototropism: plant growing towards light (sunflowers pointing to lights)

Gravitropism: plant growing in response to gravity (Growth occurs in the same direction [positive gravitropism] as the pull of gravity or the opposite direction of gravity [negative gravitropism])

Thigmotropism: plant growing in response to touch (plant changing orientation due to its touch)

Question 26

What regulates the growth of plants?

Answer 26

–>Auxin regulates horizontal growth, so it allows the cell to elongate vertically, but inhibites cell division horizontally.
—> Auxin plays a crutiol roll in** apical dominace: where the main stem (where the apical bud is) grows more (taller) than lateral buds (horizontal buds) **

–>When apical buds are cut off, it removes the main source of auxin causing lateral buds to devolpe therefore causing horizontal growth.

Question 27

What is gibberellins? (a plant regulato?)

Answer 27

Hormone which has High levels in young plants
responsible for Cell elongation and division
Can induce fruit production

Question 28

What is cytokinins? (a regulator)

Answer 28

Promote cell division
Found in meristems, young leaves, growing seeds
Slow cell aging by inhibiting breakdown of proteins

(A broad name regering to any number of plant hormones)

Question 29

What is ethylene? (regulator)

Answer 29

thylene (Gas)
“Plant stress hormone” - protect a plant against environmental stress (promotes loss of leaves in drought)

Helps thigmotropism (a tropism, a plants movement in response to touch)

Helps fruit ripening, flower opening

Senescence: processes between maturity and death (fruit/leaf drop)

Question 30

What is abscisic acid? (Regulator)

Answer 30

Growth inhibitor

Keeps leaf buds and seeds dormant (less vulnerable to damage )

Opposite of gibberellin (Within young plants and does cell elongation and division)

Closes stomata in dry conditions

Question 31

How does sucession connect to plants?

Answer 31

Sucession plays a role in shaping ecosystems, and plants are primary producers, therefore they are the main drive of sucession.

Plants pave the way for other organisisms by creating habitats and food sources, base of the food web and help with soil.

Question 32

How can humans help with sucession:

Answer 32

By planting native species after a distrubance.

–> Disturbances include forest fires, floods, huricans, etc.

Question 33

Why is second sucession faster at creating an existing ecosystem compared to primary sucession?

Answer 33

–> the present of nutrient-rich soil is still there.

Question 34

What is lignin?

Answer 34

—> A polymer, thatsupports the CELL wall in plants.,

–> makes it strong and rigid.

Question 35

How can plants protect itself from herbivores?

Answer 35

Spines (ie: cacti)

Question 36

What are regulators

Answer 36

Regulators: Chemicals produced by plant cells that regulate cell differentiation (the process of meristematic cells turning into specialized cells) and growth