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IB Biology > Topic 9 - Plants > Flashcards

Topic 9 - Plants Flashcards

(103 cards)

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1
Q

Stomata

A

Openings in leaves through which water vapour is lost. Also allow for oxygen/carbon dioxide exchange between the leaf and its environment.

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2
Q

Transpiration

A

Loss of water vapour from leaves and other aerial (i.e. exposed to air) parts of plants.

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3
Q

Blade

A

Flattened portion of a leaf.

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4
Q

Petiole

A

Stalk that attaches the blade to the stem.

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5
Q

Cuticle

A

Waxy outer layer of a leaf. Protects from water loss, insect invasion.

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6
Q

Epidermis

A

Outermost layer of leaves if waxy cuticle isn’t present; protects the plant.

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7
Q

Vascular Tissue (2 types + their functions)

A

Xylem: brings water to the leaves.

Phloem: brings the products of photosynthesis to the rest of the plant.

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8
Q

Xylem and phloem occur in ____ or ____ ____ - how are they distributed?

A

Veins, vascular bundles

They are distributed throughout the leaf to transport raw materials and products of photosynthesis; occur in the middle of the leaf to reach all cells.

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9
Q

Palisade mesophyll

A

Dense region of cells in the upper portion (i.e. highest availability of light) of the leaf. Contains many chloroplasts for photosynthesis.

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10
Q

Spongy mesophyll

A

Bottom portion of the leaf. Loosely-packed cells with few chloroplasts. Air spaces provide surfaces for gas exchange; located just above stomata so exchange is continuous.

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11
Q

Guard cells

A

Specialized cells that control the opening/closing of stomata.

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12
Q

Stomata are on the bottom of the leaf…

A

Lower temperature as less light is received; minimizes water loss.

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13
Q

Functions of xylem

A

Support for the plant, specialized water-conducting tissue.

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14
Q

Tracheids

A

Dead cells with tapered ends that connect to each other and form a continuous column.

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15
Q

Vessel elements

A

Dead cells with lignified secondary walls, often interrupted by areas of primary walls with pits/pores so water can move laterally. Form continuous columns.

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16
Q

Ends of vessel elements…

A

…have perforations in them so water can move freely up the plant.

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17
Q

Are tracheids or vessel elements more efficient in transporting water?

A

Vessel elements

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18
Q

How do stomata open/close?

A

Changes in the turgor pressure of guard cells.

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19
Q

How do guard cells open/close stomata?

A

The stoma opens when the guard cells take in water and swell - they bulge towards the outside. The guard cells sag and close the stoma when they lose water.

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20
Q

Potassium ions

A

ATP-powered proton pumps in the plasma membranes of guard cells are triggered by blue light, which triggers the active transport of potassium into the cell.

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21
Q

Osmosis (guard cells)

A

Increased solute concentration in guard cells causes water to move into them via osmosis.

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22
Q

Cohesion-tension theory

A

Water moves up xylem due to hydrogen bonding between water molecules (cohesion) and water and xylem (adhesion).

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23
Q

Function of roots

A

Provide mineral ion and water uptake for the plant.

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24
Q

Root hairs

A

Specialized epidermal structures; increase the surface area over which water and mineral ions can be absorbed.

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25
Root cap
Protects the apical meristem during the primary growth of the root through the soil.
26
Zone of cell division
New undifferentiated cells form here, corresponding with the M phase of the cell cycle.
27
Zone of elongation
Cells are enlarging in size, corresponding with the G1 phase of the cell cycle.
28
Zone of maturation
Cells become a functional part of the plant.
29
Movement of water into root cells
Water moves into plasma membranes of root hair cells through osmosis and moves to the vascular cylinder (xylem/phloem).
30
Processes that let mineral ions pass from soil to roots (3)
(1) Diffusion of mineral ions and mass flow of water that carries the ions (2) Action of fungal hyphae (3) Active transport
31
Mass flow
Passive flow of water and minerals dissolved in it into root cells.
32
Xerophyte
Plant that is adapted to arid climates; adaptations help prevent water loss.
33
Halophyte
Plant that is adapted to grow in highly saline water; adaptations help store water and dilute salt concentrations.
34
Sieve elements
Main component of phloem; form sieve tubes.
35
Sieve plates
Connect sieve elements; contain pores that allow water and organic molecules to move throughout the plant.
36
Companion cells
Regulates the activity of the adjacent sieve element.
37
Plasmodesmata
Connects companion cells to sieve elements.
38
Source
Net producer of sugar by photosynthesis or the hydrolysis of starch (e.g. leaves).
39
Sink
Uses/stores sugar (e.g. roots, buds, stems, seeds, fruits).
40
Translocation
Movement of organic molecules in plants.
41
Phloem sap
Solution of organic molecules (sugars, amino acids, hormones, RNA) dissolved in water.
42
Hydrostatic pressure
Positive pressure caused by the uptake of water at the source. Causes flow of sap in sieve tube.
43
Sugar loading
Sugar enters the sieve tube from the source via active transport. Water enters via osmosis from the surrounding cells.
44
Removal of sugar; sugar is changed to what?
Sugar enters the sink via active transport and is changed to insoluble starch.
45
Cotransport proteins
Specialized membrane proteins that allow for passive and active transport.
46
Dermal tissue
Outer covering that protects from physical agents and pathogens, prevents water loss.
47
Ground tissue
Thin-walled cells; storage, photosynthesis, support, secretion.
48
Vascular tissue
Xylem and phloem; carry out long-distance conduction of water, minerals, and nutrients, provide support.
49
Meristematic tissue
Same function as stem cells; all tissue types are derived from meristem.
50
Indeterminate growth in plants
Doesn't stop at a certain size.
51
Intials
Cells that remains meristematic after the division of meristematic tissue.
52
Derivatives
Cells that begin differentiation after a meristem cell divides.
53
Apical meristems
Occur at the tips of roots and stems.
54
Shoot apex
Apical meristem and; surrounding developing tissue. Produces new tissue and causes primary growth through mitosis and cell division.
55
Lateral meristems
Allow secondary growth (i.e. increased thickness).
56
Vascular cambium
Produces secondary vascular tissue; xylem on the inside, phloem on the outside.
57
Cork cambium
Occurs in bark, produces cork cells of outer bark.
58
Tropisms
Growth/movement to directional external stimuli.
59
Phototropism
Plant growth in response to light; positive with stems, negative with roots.
60
Auxins
Plant hormones that cause positive phototropism in shoots and seedlings.
61
How does auxin work?
Increased flexibility in plant cell walls result in the elongation of cells, which allows for growth towards light.
62
Auxin efflux pumps
Specialized membrane proteins that move auxins out of cells that are close to light.
63
Auxin influx
Entry of auxin into a cell
64
Indoleacetic acid (IAA)
Auxin that causes cells to elongate and the stem to curve towards light.
65
Auxin and gene expression
Whenever auxin affects cell growth, it does so by changing the pattern of gene expression. Often occurs by interacting with the repressor of a certain gene.
66
Angiosperm
Plant that has a flower.
67
Monocots
Angiosperms whose seeds have 1 cotyledon.
68
Dicots
Angiosperms whose seeds have 2 cotyledons.
69
Sepals
Protect the developing flower bud.
70
Petals
Colourful; attract pollinators.
71
Pistil/Carpel
Female reproductive structure of flower.
72
Stigma
Sticky top; traps pollen.
73
Style
Thin tube, transports pollen from the stigma to the ovary. Supports the stigma.
74
Ovary
Where ovules develop into fruit.
75
Ovule
Contains egg cell, which develops into a seed after fertilization.
76
Stamen
Male reproductive structure of flower.
77
Filament
Thin stalk, supports the anther.
78
Anther
Knob-shaped structure, produces pollen (male sex cells).
79
Two generations in plant life cycle:
Gametophyte (haploid) and sporophyte (diploid)
80
Products of gametophyte generation
Plant gametes (via mitosis)
81
Products of sporophyte generation
Spores (via meiosis)
82
Pollination
Pollen (w/male sex cells) is placed on the stigma.
83
Vectors of pollination (5)
Wind, insects, birds, water, animals
84
Self-pollination
A plant's pollen falls on its own stigma. Reduces genetic variation.
85
Cross-pollination
Pollen from one plant falls on the stigma of another plant. Increases genetic variation.
86
Fertilization
Male and female sex cells form a diploid zygote.
87
Testa
Protective coat around seed.
88
Cotyledon
Seed leaves; store nutrients.
89
Micropyle
"Scar" where pollen tube entered the ovule. Water enters here.
90
Hypocotyl
Embryonic stem
91
Epicotyl
Embryonic shoot
92
Radicle
Embryonic root
93
Seed dormancy
Period of low metabolism; no growth/development occurs.
94
Germination
Seed develops into a functional plant.
95
Conditions for germination
Water, oxygen, temperature (enzyme action); some need a broken testa, exposure to fire.
96
Large numbers of seeds are produced because...
...many seeds don't make functioning plants due to several dangers; quantity of seeds ensures survival of species.
97
Photoperiodism
Plant response to light regarding relative lengths of day and night.
98
Long-day plants
Flower when days are longer.
99
Short-day plants
Flower when days are shorter.
100
Day-neutral plants
Flower whenever, day length doesn't matter.
101
Phytochrome (2 forms)
Blue-green pigment that controls flowering. Pr in inactive and absorbs red light (becomes Pfr) Pfr is active and absorbs far red light (becomes Pr).
102
Pfr in long-day plants
Promotes flowering; binds to receptor and promotes transcription of genes.
103
Pfr in short-day plants
Inhibits flowering; binds to receptor and inhibits transcription of genes.

IB Biology (2 decks)

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