Plants Flashcards

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1
Q

Root system-

A

underground- absorbs

water and minerals from the soil

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2
Q

Shoot system-

A

aboveground- absorb light and CO2 Stem o Leaves o Flowers/ fruits

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3
Q

Ground tissue system-

A

plant body–functions in photosynthesis, storage, and support

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4
Q

Vascular tissue system-

A

conducting system–transports water, minerals, food

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5
Q

Dermal tissue system-

A

provides covering for plant

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6
Q

Ground tissue system

A

Composed of 3 different types of tissue. Growing plant cell secretes thin flexible primary cell wall. After stops growing- secondary cell wall- inside primary cell in between plasma membrane and primary cell wall
more rigid and cell can no longer grow after scw
put down. Each of the three tissues contain different types of cell walls, making the structure of the cells range from very soft and flexible (most common parts of plants) to very hard (cells found in wood, bark, nuts, etc)

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7
Q

Xylem

A

Vascular. conducts water and dissolved nutrient materials from roots to stems and leaves. Cells are hollow and dead at maturity

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8
Q

Phloem

A

Vascular. conducts food materials (carbs formed by photosynthesis). Cells alive at maturity

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9
Q

Epidermis-

A

Dermal tissue system. outermost layer of herbaceous plants. Transparent- no chloroplasts. Secrete waxy cuticle which restrict water loss. has stomata.

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10
Q

stomata

A

pores in epidermis that allow for gas exchange

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11
Q

Guard cells-

A

surround stomata

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12
Q

Trichomes-

A

outgrowth or hairs in epidermis (called root hairs in roots)

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13
Q

Periderm-

A

replaces epidermis in woody plants

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14
Q

Leaf tissues

A

Upper epidermis covers upper layer, lower epidermis covers lower layer. Mesophyll, bundle sheath, veins

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15
Q

Mesophyll-

A

photosynthetic ground tissue of the leaf. Loosely arranged with many air spaces- allows for rapid gas diffusion. Palisade mesophyll- closely packed, spongy mesophyll looser.

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16
Q

Bundle sheath-

A

nonvascular cells surrounding larger veins

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17
Q

Veins-

A

vascular bundles containing xylem and phloem

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18
Q

Transport in Plant Body

A

Water and dissolved nutrient minerals are transported from roots to other parts of the plant in xylem- only moves upward. Dissolved sugar is translocated in phloem- can move upward or down. Driven by physical forces, not by a pumping organ

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19
Q

Transpiration-

A

loss of water vapor by evaporation , mostly through stomata

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20
Q

Environmental factors affecting transpiration:

A

Higher temps and more light–>stomates to open more
wind and dry air–more transpiration
humidity–less transpiration

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21
Q

Importance: transpiration

A

responsible for water movement from soil to leaves

cools stem and leaves and Distributes dissolved minerals through plants

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22
Q

how might transpiration be harmful?

A

Too much transpiration- plant can wilt and die

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23
Q

what cycle is transpiration a part of?

A

Part of hydrologic cycle- water cycles from ocean and land back to atmosphere, then back to ocean and land Water evaporates from leaves and stems to form clouds in atmosphere

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24
Q

Guttation-

A

liquid water is forced out of plant. Occurs at night, when no transpiration is occurring but there is moist soil

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25
Q

xylem (water potential)

A

Remember that water moves from an area of higher water potential to an area of lower (more negative) water potential, meaning an area with more dissolved solutes. When soil is moist, it has a high water potential, although it is slightly negative because it has some dissolved minerals (pure water has water potential of zero). Root cells have a more negative water potential due to many dissolved solutes- therefore water moves by osmosis from soil into root

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26
Q

Tension-cohesion model (or transpiration-cohesion model)

A

Loss of water through transpiration in leaves causes a tension that extends from leaves down to stems and roots, drawing water up the stem xylem to the leaf cells. Possible only as long as there is an unbroken column of water in xylem throughout the plant- maintained by cohesion of water molecules to each other and adhesion of water molecules to xylem. Because there is a water potential gradient from the least negative (soil) up through the plant to the most negative (atmosphere), water is pulled up from soil through plant. Tension-cohesion model is powerful enough to pull water upward 500 ft.

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27
Q

phloem system

A

Before loaded into phloem, glucose produced during photosynthesis is converted into sucrose. Fluid can move both upward and downward. Sucrose moves from a source to sink

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28
Q

Controlling water loss at the stomata

A

Controlled by changes in shape of guard cells

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29
Q

guard cells opening up

A

Water moves into guard cells- they become turgid and bend slightly, moving apart to produce a pore

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30
Q

guard cells closing

A

Water leaves guard cells- they become flaccid and the cell walls collapse, closing the pore

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31
Q

How does blue light open stomata?

A

Pigment in guard cells is stimulated by blue light. Triggers activation of enzymes called kinases located in the cell membrane. These enzymes cause potassium ions to flow in, followed by water bc of water potential, and the stomata open

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32
Q

Closing of stomata

A

Caused by a hormone called abscisic acid (ABA), which binds to receptors on a guard cell’s plasma membrane. Potassium ions leave the cell, and water follows by osmosis. stomata close.

33
Q

low conc of CO2 does what to stomata?

A

opens them

34
Q

dehydration does what to stomata?

A

closes

35
Q

Circadian rhythms-

A

24 hour cycle of opening and closing stomata

36
Q

Alternation of generation-

A

portion of life cycle in multicellular haploid stage, portion in multicellular diploid stages. diploid sporophyte, haploid gametophyte

37
Q

Gametophyte generation-

A

haploid- give rise to gametes by mitosis

38
Q

Pollination-

A

transfer of pollen grains from anther to stigma.

39
Q

Double fertilization step 1

A

Two sperm cells from generative cell move down pollen tube of pollen grain and enter ovule.

40
Q

Germination

A

the process of seed sprouting and growth of young seedlings into mature plants

41
Q

Requirements for germination:

A

Imbibition, Large supply of oxygen required to power aerobic respiration to energy for germination, between 25 and 30 C, some require light, some require long low temperature period before seeds can break dormancy and germinate

42
Q

Imbibition

A

absorption of water by dry seed

43
Q

Photoperiodism-

A

response of plant to lengths of daylight and darkness. there is a group that doesn’t respond to photoperiodism

44
Q

Short-day plants-

A

flower when night is > 12-14hr

45
Q

Long-day plants -

A

Flower when nights are < 12 hr

46
Q

Intermediate-day plants-

A

Do not flower when night length is too short or long

47
Q

Phytochrome-

A

type of photoreceptor that absorbs light. Absorbs two forms of light- red and far-red

48
Q

Red light-

A

present at sunrise, causes phytochrome to shift from inactive form to active form

49
Q

Far red light

A

at sunset and darkness shift phytochrome to inactive

50
Q

pfr

A

active form phytochrome

51
Q

What would happen if a pulse of red light interrupted the dark phase in a plant?

A

activated the phytochrome, which made the plants act as if the night were short

52
Q

Nastic movements-

A

quick responses that are temporary and reversible

53
Q

Tropism-

A

slower, directional growth response- results in change in position in part of the plant. + or -, but irreversible. Under hormonal control

54
Q

Phototropism-

A

growth caused by light.

55
Q

Gravitropism-

A

growth in response to direction of gravity.

56
Q

Thigmotropism-

A

growth in response to mechanical stimulus, such as contact with solid object. Ex- twirling of stems of vines

57
Q

why do higher temps and more light cause higher rate of transpiration

A

more light –> more heat

more light/heat –> stomates to open more

58
Q

why wind and dry air–more transpiration

A

bc water potential causes dry air to be less conc than water in stomata; wind blows water vapor away and causes more water to take place

59
Q

why humidity–less transpiration

A

bc a lot of water in air already so water potential difference isn’t so stark

60
Q

pollen grain

A

A pollen grain contains a tube cell, which forms a pollen tube towards the egg, and a generative cell, which contains two sperm cells.

61
Q

double fertilization step 2

A

One sperm cell unites with egg, forming zygote. Second sperm fuses with a central cell found within the ovule that contains two haploid nuclei, forming a triploid (3n) endosperm.

62
Q

endosperm

A

surround developing plant in seed, functions as nutrients.

63
Q

double fertilization reason for name

A

Called double bc two cell fusions. (“One sperm cell unites with egg, forming zygote. Second sperm fuses with a central cell”)

64
Q

In flowers- sporophyte and gametophyte n and locations ish

A

In flowers- diploid sporophyte is large and independent, haploid gametophyte is located in the flower

65
Q

negative gravitropism-

A

Stems- grows away from direction of gravity,

66
Q

positive gravitropism-

A

Roots- grows toward gravity.

67
Q

Root cap-

A

site of gravity perception in roots.

68
Q

Positive phototropism-

A

shoot tips bend towards the light. Auxin moves down from the coleoptile, making it grow

69
Q

Auxin

A

a plant hormone

70
Q

coleoptile

A

the tip of the plant

71
Q

why do plants bend toward light in phototropism?

A

Auxin moves faster on through the cells on the side less exposed to light, making them grow longer, so plant bends toward light.

72
Q

what happens to the ovule and ovary after fertilization?

A

Ovule develops into a seed, ovary develops into a fruit.

73
Q

Sporophyte generation-

A

diploid- forms spores by meiosis

74
Q

(Pr)

A

inactive phytochrome

75
Q

active form phytochrome results

A

When in active form (Pfr), the phytochrome can induce gene transcription

76
Q

what happens when genes of plants are transcribed?

A

seed germination, shoot elongation and branching, leaf expansion, and flower, fruit and seed formation

77
Q

source (phloem)

A

area of excess sugar supply (leaf)

78
Q

sink (phloem)

A

area of storage/use for sugar