Bio Exam 2

Front 1

Xylem

Back 1

Where water and mineral are transported

Front 2

Stomata

Back 2

Control the loss of water and the uptake of CO2

Front 3

Osmosis

Back 3

Passive movement of water across a membrane. Low to high concentration

Front 4

Vacuole

Back 4

Filled with solutes pumped in by transporter proteins.

Front 5

Flaccid

Back 5

When the wall in not exerting pressure on the protoplast

Front 6

Turgor Pressure

Back 6

The cell internal pressure increases and resists further entry of water

Front 7

Turid

Back 7

when a cell has significant positive pressure, when not turgid plants wilt

Front 8

Bulk Flow

Back 8

In the Xylem and phloem the flow of water and dissolved fluids is driven by pressure gradients (negative-tension)(positive-turgidity)

Front 9

Aquaporins

Back 9

membrane channel proteins that water passes through rapidly. Rate of movement can be regulated but direction can not.

Front 10

Mineral Ions

Back 10

They cannot pass membrances without transport proteins

Front 11

Electrochemical gradient

Back 11

uptake against the electrochemical gradient of an ion requires ATP hydrolysis

Front 12

Apoplast

Back 12

Where water and minerals move into the stele. In the stele minerals enter the apoplast by active transport and water moves into the apoplast by osmosis

Front 13

Symplast

Back 13

a continuous meshwork that water can move through until it reaches the symplast (Casparian strips of the endodermis)

Front 14

Plasmodesmata

Back 14

where water passes through the cells

Front 15

Casparian Strips

Back 15

Separate the apoplast of the cortex from the spoplast of the stele

Front 16

Endodermal Cells

Back 16

Where water and ions can enter the stele only through

Front 17

Xylem

Back 17

Water and mineral end up in xylem, forming the xylem sap. Xylem vessels are dead and vacant. Transport a large amount of water over great distances

Front 18

Tenssion

Back 18

Created by the evaporation of H2O from leaves, causes xylem sap to be pulled forward

Front 19

Transpiration- Cohesion-Tension mechanism

Back 19

requires no energy from the plant, water movement is driven by transpiration, mineral ions in xylem sap rise passively with the water, transpiration cools leaves

Front 20

Stomata

Back 20

The waxy cuticle leaf and stem epidermis minimizes water loss, but prevents gas exchange

Front 21

Stomata Pores

Back 21

In the leaf epidermis they allow CO2 to enter leaves and water is lost

Front 22

Guard Cells

Back 22

control opening and closing

Front 23

Control the less of water and the uptake of CO2

Back 23

Refer to Chapter 35 Review

Front 24

Plants limit water loss by controlling the stomata in two ways

Back 24

1) Regulating Stomatal opening and closing. 2) Controlling the total number of stomata

Front 25

Abscisic Acid

Back 25

Acid that activates a K+ channel in the PM of guard cells when a plant is under water stress

Front 26

Translocation

Back 26

Movement of carbohydrates and other solutes through the phloem. Substances are translocated from sources to skins. Sources (leaves/storage organs, export sugars) Skins (roots/reproductive organs, consume sugar)

Front 27

Sieve tube elements

Back 27

Part of the phloem. Meets end-to-end. Plasmodesmata in end walls enlarge to from sieve plates, most of the cells contents are lost

Front 28

Companion cells

Back 28

produced as daughter cells along with the sieve tube element when a parent cell divides

Front 29

Plamodesmata

Back 29

link companion cells with sieve tube elements

Front 30

Phloem loading

Back 30

Transport of solutes from sources into sieve tubes

Front 31

Land Plants

Back 31

Embryophytes (derived trait) development from embryo protected by tissues of the parent plant . Starch is a major source of energy

Front 32

Embryophytes

Back 32

development from embryo protected by tissues of the parent plant

Front 33

10 major clades of land plants

Back 33

Vascular plants: (tracheophyts) (7 clades) all have conducting cells known as tracheids

Nonvascular land plants: remaining three clasdes; liverworts, hornworts, and mosses

Front 34

Charales

Back 34

closet relative of land plants. Both Chara and land plants; retain eggs, have plamodemata, branching and apical growth, similar chloroplasts and cytokinesis mechanisms

Front 35

Cuticle

Back 35

waxy covering that retards water loss

Front 36

Stomata

Back 36

opening in stems and leaves, regulating gas exchange

Front 37

Gametangia

Back 37

enclosing gamets

Front 38

Pigments

Back 38

protect against UV radiation

Front 39

Spore

Back 39

walls containing sporopollenin (protects from decay)

Front 40

Mutalistic relationship with fungi

Back 40

uptake of nutrients from soil

Front 41

Nonvascular land Plants

Back 41

first land plants, only have a thin cuticle (grow in moist environments). No system to conduct water from soil to plant body. Water moves through mats by capillary action, minerals distributed through diffusion, swimming sperm. Can frown on marginal surfaced, relationship with fungi

Front 42

Alteration of Generations

Back 42

Includes multi-cellular diploid and multi-cellular haploid stages. Gametes are produced by mitosis, meiosis produces haploid organisms

Front 43

Diploid (2n)

Back 43

Sporophyte: undergoes meiosis to produce haploid

Front 44

Haploid (n)

Back 44

Gametophyte

Front 45

Evolution of land plants

Back 45

reduction of the size of the gametophyte generation in plant evolution.

Front 46

Gametophyte Generation

Back 46

in nonvascular gametophyte is larger, longer lived, and more self-sufficient than the sporophyte. As plants evolved the sporophyter generation became larger, decreasing dependance on liquid water

Front 47

Sporophyte Generation

Back 47

Is nutritionally dependant upon the gametophyte. As plants evolved became more dependent of sporophyte generation decreasing dependance of liquid water

Front 48

Land Plant fertilization

Back 48

sperm must swim to archegonium or be carried there by rain drop splashes, egg releases chemical attractants for sperm, water required, egg and sperm from diploid zygote- develops into a multicellular diploid sporophyte embryo, base of archegonium grows to protect embryo

Front 49

Tracheids

Back 49

Principle water conducting elements of xylem in all vascular plants. Transport of water and minerals, rigid structure support

Front 50

Features of vascular plants

Back 50

Have branching independent sporophyte. Produce more spores and develop in complex ways, nutritionally independent from the gametophyte

Front 51

Lycophytes & Monilophytes

Back 51

true roots and leaves and two types of spores

Front 52

Leafs (true vascular tissue)

Back 52

Microphylls & Megaphylls

Front 53

Homosporous

Back 53

most ancient type of vascular plants. Produce one type of gametophyte, both archegonium and antheridium

Front 54

Heterosporous

Back 54

plants produce two types of spores; Megaspore/Microspore

Front 55

Megaspore

Back 55

developed into a female gametophyte (eggs)

Front 56

Microspore

Back 56

male (sperm)

Front 57

Clades of Seedless plants

Back 57

some have leafy gametophytes; some have thalloid gametophytes

Front 58

Mosses (bryonphyta)

Back 58

Seedless! Have stomata (water and gas exchange)

Front 59

Sphagnum moss

Back 59

Cool swampy places, upper layers compress lower layers, forming peat (fuel/coal)

Front 60

Hornworts

Back 60

Gametophytes are flat plates of cells. Single, large, chloroplast. Sporophyte- no stalk, basal region capable of indefinite cell division. Internal cavities filled with nitrogen- fixing cynobacteria

Front 61

Horsetails & whisk ferns

Back 61

both monophyletic, ferns are NOT

Front 62

Ferns

Back 62

Leptosporangiate ferns: most ferns belong to this clade. True roots, stems and leaves

Front 63

Evolution of seed plants

Back 63

seed plants became the dominant vegetation, major groups of gymnosperms, features that contributed to the success of the angiosperms, plants support our world

Front 64

Secondary growth

Back 64

Thickened woody stems of xylem

Front 65

Earliest Plants

Back 65

Devonian; seed ferns

Front 66

Living seed plants

Back 66

Gymnosperms-pines and cycads
Angiosperms- flowering plants
Seed plants are heterosporous
microsporangium and megaspores (nutritionally dependent on the sporophyte , embryo become dominant forming multicellular seeds

Front 67

Gymnosperms

Back 67

Naked-seeded. All except gnetophytes have only tracheids for water conduction and support

Front 68

Conifers

Back 68

Naked-seeded. Some have soft fleshy fruit-like tissue, animals eat their seeds. Today conifers dominated many forests

Front 69

Cones

Back 69

contain the reproductive structures of conifers
Megastrobilus: female cone, protected by a tight cluster of wood scales (modification of branches
Microstrobilus: male cone

Front 70

Angiosperm traits

Back 70

double fertilization, endosperm-nutritive tissue in seeds, ovules and seeds enclosed in a carpel, flowers, fruits, phloem with companion cells, reduced gametophytes

Front 71

Perfect Flowers

Back 71

self pollinating (disadvantageous)

Front 72

Animal-pollinated

Back 72

entice with nectar and pollen, co-evolved relationships

Front 73

Angiosperm Life Cycle

Back 73

Heterporous: Male (pollen) Female (ovule): develops into a seed with a diploid zygote and a triploid endosperm. Embryo consists of an embryonic axis (becomes stem and root) one or two cotyledons(seed leaves)

Front 74

Monocots

Back 74

one cotyledon (seed leaves)
includes grass, cattails, lilies, etc.

Front 75

Eudicots

Back 75

two cotyledons. Most seed plants, herbs, vines, trees, shrubs

Front 76

Photosynthesis

Back 76

Plants take in CO2, produce carbohydrates, and release water and O2, REDOX reaction, convert energy to chemical energy as ATP and NADPH

Front 77

Electromagnetic radiation

Back 77

Light

Front 78

Wavelength

Back 78

inversely proportion to the energy of light

Front 79

Photons

Back 79

light behaves as particles. When a photon meets a molecule it can be:
• Scattered—photon bounces off the molecule
• Transmitted—photon is passed through the molecule
• Absorbed—molecule acquires the energy of the photon. The molecule goes from ground state to an excited, higher energy state.

Front 80

Absorption spectrum

Back 80

absorption of light as a function of wavelength

Front 81

Action spectrum

Back 81

Biological activity as a function of wavelength

Front 82

Pigments used in photosynthesis

Back 82

Chlorophylls a and b. Accessory pigments: Absorb in red and blue regions, transfer the energy to chlorophylls—carotenoids.

Front 83

When a pigment molecule absorbs a photon the energy can be...

Back 83

Released as heat and/or light. Transferred to another molecule. Used for a chemical reaction

Front 84

Energy can pass to another molecule if:

Back 84

Target molecule is very near. orientation is correct. Has appropriate structure.

Front 85

Antenna systems: light harvesting complexes

Back 85

Photosystem: consists of multiple antenna systems and their pigments and surrounds a reaction center (RC) –a specialized (Chl a): 250 tp 400 LH Chl/ RC CHL

Front 86

The reaction center converts light energy into chemical energy.

Back 86

• The excited chlorophyll a molecule (Chl*) is a reducing agent (electron donor).
• A is an acceptor molecule (oxidizing agent).
• A and RC-Chl are members of the chloroplast electron transport chain.
• The final electron acceptor is NADP+.
 NADP+ + 2 e- + 2 H+ → NADPH
• Noncyclic electron transport: Light energy is used to oxidize water → O2, H+, and reduce NADP+ to NADPH:
• H2O + NADP+ → ½ O2 + NADPH + H+

Front 87

Two photosystems required in noncyclic electron transport.

Back 87

Photosystem I: Reduces NADP+ to NADPH
Photosystem II: Oxidizes H2O to O2

Front 88

Autotrophs

Back 88

Obtain carbon from CO2 in the atmosphere through fixation by photosynthesis

Front 89

Nitrogen

Back 89

enters plants mostly as a result of bacterial activity

Front 90

Mineral nutrients

Back 90

Obtained from the soil: sulfur, phosphorus, magnesium, iron, calcium
Soil Solutions: minerals dissolved as ion in the soil solution

Front 91

Essential element

Back 91

one required to complete its life cycle

Front 92

Macronutrients

Back 92

at least 1g per Kg of dry plant matter

Front 93

Micronutrients

Back 93

less than 100mg per Kg

Front 94

Deficiency symptoms

Back 94

help in the diagnosis of which nutrient is lacking, and the nutrient can be applied

Front 95

Soil

Back 95

provides mechanical support, mineral nutrients, water, and oxygen. Living components: plant roots, bacteria, fungi, protists, and animals. Non-living components: rock fragments, sand, silt, and clay, Organic materials (dead), water and minerals

Front 96

Topsoil

Back 96

Mineral nutrients tend to be leached (dissolved and carried downwards) from this layer. Agriculture depends on topsoil.

Front 97

Mechanical weathering

Back 97

physical breakdown of rocks into soil particles by wetting, drying, and freezing

Front 98

Chemical weathering

Back 98

oxidation by atmospheric oxygen, hydrolysis (reaction with water), acids (carbonic acid)

Front 99

Fertilizers

Back 99

N, P, and K
Organic fertilizers improve soil structure, root growth, and drainage. Nutrients are released slowly

Front 100

Fungi/ Bacteria & nutrient uptake

Back 100

Symbiotic relationships
o Mycorrhizae: Associations of fungi and plant roots.
o Mycelium: Multicellular fungus composed of rapidly growing individual tubular filaments called hyphae.
• Roots often can’t reach all the nutrients available in the soil
o mutualistic relationship, fungus gets carbohydrates
• Strigolactones; stimulate rapid growth of fungal hyphae toward the root
• Requirements:
o Strong reducing agent to transfer H+ and e- to N2 and intermediate products
o Lots of ATP
o Nitrogenase: catalyze the reaction

Front 101

Nitrogen Fixation

Back 101

Refer to Chapter 36 outline

Front 102

Carnivorous and Parasitic Plants

Back 102

Found in boggy habitats that are acidic and nutrient deficient . Get N by capturing animals and digesting proteins

Front 103

Parasitic Plants

Back 103

Several parasitic species lack genes in chloroplast genome
o Hemiparasites: can photosynthesize, but derive mineral nutrients from other living plants
o Holoparasites: completely parasitic, do not perform photosynthesis

Front 104

Meristems

Back 104

allow growth throughout the plants life

Front 105

organ formation

Back 105

new organs can develop throughout life

Front 106

differential growth

Back 106

they can grow the organs most needed

Front 107

Regulators of plant development

Back 107

Environmental cues, receptors, Hormones, Photoreceptors: pigments associated with proteins (light acts directly on photoreceptors which regulate development. Plants genomes (ultimately what determines plant development)

Front 108

Seeds: Dormant

Back 108

as seed germinates it takes up water. embryo obtains nutrients from the endosperm. Germination is complete once radicle(embryonic root) emerges --> now seeding. Photoreceptors direct stage of development

Front 109

Mechanisms to maintain dormancy

Back 109

seed coats may be abraded by physically or in the digestive tract . soil microorganisms and freeze-thaw cycles may soften seed coats. Fire can melt waterproof was in seed, or by cracking the seed coat. Chemical inhibitors may be leached. Light is required for germination in some seeds.

Front 110

Advantages of seed dormance

Back 110

survival in harsh conditions. Prevent germination while still attached to parent plant. Long-distance dispersal of seeds.

Front 111

Gibberllins

Back 111

"Foolish seeding disease" rice causes plants to grow rapidly and to die before producing seed. Caused by ascomycete fungus- releases a molecule that stimulated growth Gibberlin. Gibberellin applied to seedlings of the dwarf strains of corn or tomatoes caused them to grow as tall as wild type plants.(stimulate stem elonation, regulate fruit growth, mobilize food reserves in cereal plants, promote bolting)

Front 112

Axuin

Back 112

Phototropism is the growth of plant organs towards light. Causes plant movements by growth. When light strikes a coleptile on one side, auxin moves to the other side, elongation increases on that side. Coleoptile bends toward the light

Front 113

Phototropism

Back 113

Membrane receptor (phototropin) absorbs blue light. When activated, a signal transduction pathway results in redistribution of auxin transport carriers.

Front 114

Gravitropism

Back 114

plastids called amyloplasts store starch and settle on the downward side of a cell in response to gravity and trigger auxin transport

Front 115

Auxins role in plant development

Back 115

root formation, inhibition of leaf abscission, inhibition of axillary bud development, rate and direction of growth

Front 116

Axuin and growth

Back 116

loosens cell walls to allow for cell expansion (ie growth). Driven primarily by water growth. Decrease in PH, expansion triggered by low PH

Front 117

Cyotkinins

Back 117

Adenine derivates (cytokinins) stimulate cell division: stimulate rapid cell division, cause light-requiring seeds to germinate in darkness, promote formation of shoots, inhibit stem elongation causing lateral swelling of stems and roots, stimulate axillary buds to grow, delay senescence of leaves

Front 118

Ethylene

Back 118

Is produced in all parts of the plant, promotes senescence, promotes leaf abscission and fruit ripening, inhibits stem elongation and gravitropism

Front 119

Brassinosteriods

Back 119

Stimulate cell elongation, pollen tube elongation, and vascular tissue differentiation, but inhibit root elongation. If lacking plants develop slowly are dwarf or infertile

Front 120

Plants respond to two aspects of light:

Back 120

Quality- the wavelength of light that can be absorbed by molecules in the plant
Quantity- the intensity and duration of light exposure

Front 121

Blue-light receptors

Back 121

mediate the effect of higher-intensity blue light

Front 122

Phytochrome

Back 122

mediates the effects of red light. Photomorphogenesis—physiological and developmental events that are controlled by light.Processes are induced by red light → far red light can reverse these however. • Two inconvertible forms. The default or “ground” state (Pr) absorbs red light, and then is converted into Pfr.
The Pfr form absorbs far-red light; and is converted back to Pr.

Front 123

Carpels

Back 123

female sex organs

Front 124

Stamens

Back 124

male sex organs

Front 125

Monoecious

Back 125

plants that bear both male and female flowers

Front 126

Dioecious

Back 126

plants that bear either male-only or female-only flowers

Front 127

Embryo Sacs

Back 127

Megagmetophytes

Front 128

Pollen Sacs

Back 128

Microgametophytes

Front 129

Pollination

Back 129

transfer of pollen from anther to stigma

Front 130

Germination

Back 130

germination of the pollen grain involves uptake of water and growth of the pollen tube. Pollen tube grows through the style to reach the ovule

Front 131

Mature pollen grains

Back 131

consist of two cells, the larger tube cell encloses the generative cell. The tube cell nucleus directs growth of the pollen tube through the style tissue to the embryo sac. o the generative cell divides once to form two haploid sperm cells.
o The zygote nucleus begins mitotic division to form the new sporophyte embryo.
o The triploid nucleus undergoes mitosis to the endosperm. It will later be digested by the developing embryo.

Front 132

Integuments

Back 132

tissues surrounding the megasporangium develop into the seed coat. The carpel becomes the wall of the fruit that surrounds the seed

Front 133

Suspensor

Back 133

one daughter cell becomes the embryo the other become a supporting structure

Front 134

Seed lose water and become dormant

Back 134

Sugars and proteins become concentrated and protect membranes and proteins from damage. Abscisic acid(ABA) controls seed development. The ovary wall and seed develop into a fruit - Two functions: Protect seeds, aid in dispersal

Front 135

Apical Meristems

Back 135

continuously produce leaves, stems, and axillary buds

Front 136

Inflorescence meristem/ floral meristems

Back 136

give rise to flowers

Front 137

Meristems identity genes

Back 137

start a cascade of further gene expression

Front 138

Photoperiodism

Back 138

control of flowering and other responses by length of day or night.

Front 139

Short-day plants

Back 139

flower when the day is shorter than a critical maximum. They flower in late summer or fall. Critical night length- nine hours

Front 140

Long-day plants

Back 140

flower when the day is longer than a critical maximum. they flower midsummer

Front 141

Florigen

Back 141

if just one leaf on the plant gets proper amount of sunlight plant will flower. FT (FLOWERING LOCUS T) codes for florigen. FT is a small protein and can travel through plasmodesmata.

Front 142

Vernalization

Back 142

flowering is signaled by cold temperatures

Front 143

Asexual Reproduction

Back 143

Produces clone, well adapted to environment, commonly live in unstable environments, rapid reproduction, allows them to survive in shifting sands