Plants Flashcards

1
Q

Fungi: Generalities

A

1) filamentous
2) non-motile
3) cell wall contains chitin
4) make spores - individual cells capable of giving rise to a new organism
5) non-photosynthetic
6) asexual and sexual life cycles
7) live in their food, secrete enzymes to digest food and then absorb broken down compounds

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2
Q

heterotrophic bacteria

A

allow fungi to “recycle”

decayers are essential to the continuation of a community

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3
Q

hypha

A

filaments in fungi
many hypha = hyphae
many hyphae = mycelium

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4
Q

fungi: asexual reproduction

A

hyphae breaks into pieces –> new fungus

hyphae make spores

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5
Q

fungi: sexual life cycle

A

3 stages:
1) hyphae growing in soil - monokaryon or dikaryon after mating
2) dikaryons make up the mushroom
3) gills under mushroom –> fusion of the nuclei
genetic exchange –> meiosis, makes N spores
spores are dispersed to new areas to begin life cycle again

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6
Q

lichen

A

mutually symbiotic associations between fungi and alga
provides structure and protection, absorbs minerals
lichens secrete acid into rock, breaking it down and creating soil

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7
Q

algae

A

the first “plants” - 1.5 billion years ago
classifications: greens, reds, brown, yellows
based on - composition of cell wall, presence of flagella, unicellar (yellow) or multicellular (green/red/brown)

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8
Q

yellow algae

A

diatoms and dinoflagellates
single-celled
tend to grow along coasts in undisturbed waters
contribute to algal blooms - critical photosynthetic activity
silica embedded in cellulose cell wall, settle and accumulate at ocean bottom
diatomaceous earth - made up of shells/walls of diatoms

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9
Q

alternation of generations

A

alternation between haploid and diploid generations, fertilization is delayed
(2N) sporophytes undergo meiosis to produce (N) spores, which germinate to form new (N) gametophyte plants
(N) male and female gametophytes produce (N) male and female gametes
fertilization occurs
new 2N plant

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10
Q

problems with plants moving onto land

A

how to fertilize in environment lacking water (no longer buoyant)
support
transport of water from roots
gametes may dry out and die

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11
Q

bryophytes

A

mosses, liverworts
no vascular system
1) gametophyte (N) is independent - the largest, photosynthetic
2) sporophyte (2N) - small, totally dependent on gametophyte
gametes released when water comes
protection for sperm: jacket of cells called antheridium
protection for egg: archegonium

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12
Q

pteridophytes

A

ferns
main feature is the frond (specialized leaf-like structures)
on the frond - meiosis occurs to make spores (N)
spore-bearing leaves = sporophylls
male gamete has flagella
needs water for fertilization
(2N) sporophyte –> meiosis –> spores (N) –> gametophyte (N) –> gametes (N) –> new embryo (2N) –> (2N) sporophyte
independent sporophyte and gametophyte

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13
Q

gymnosperms

A

cone-bearing plants, “naked seed”
cones house the female reproductive life cycle:
scales - produce spores, equivalent to megasporophyll
fertilization occurs when pollen from the male cone arrives at the female cone
embryo is surrounded by (N) gametophyte tissue
mature gametophyte = ovule (before fertilization)

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14
Q

summary

A

algae: alternation of generations, free-living sporophyte and gametophyte, flagellated gametes, no arch/anther, no seed
bryophytes: alternation of generations, free-living gametophyte only, flagellated games, arch/anther present, no seed
ferns: alternation of generations, free-living sporophyte and gametophyte, flagellated gametes, arch/anther present, no seed
gymnosperms: alternation of generations, free-living sporophyte only, no flagellated gametes, archegonium only, seed present
angiosperms: alternation of generations, free-living sporophyte only, no flagellated gametes, no arch/anther, seed present

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15
Q

free-living sporophyte

A

algae, ferns, gymnosperms, angiosperms

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16
Q

free-living gametophyte

A

algae, bryophytes, ferns

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17
Q

flagellated gametes

A

algae, ferns, bryophytes

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18
Q

archegonium present

A

bryophytes, ferns, gymnosperms

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19
Q

antheridium present

A

bryophytes, ferns

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20
Q

seed present

A

gymnosperms, angiosperms

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21
Q

angiosperms

A

“seed in a container” - distinguished by fruits, flowers
flower = determinate axis along which are arranged the floral organs
determinate = having a defined period of growth
double fertilization

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22
Q

flower: female reproductive parts

A

carpel: made up of stigma, style, ovary
petals and sepals are not fertile/reproductive
ovary –> houses megasporangium, which creates the N spores
megaspores will become new female gametophyte
inside ovules: 7 cells, 8 nuclei (polar nuclei are double) and egg

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23
Q

flower: male reproductive parts

A

stamen: made up of anther and filament
anther makes male gametes (pollen nuclei), which eventually go to the stigma
microspores are made in anther through meiosis (anther is basically sporangium)

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24
Q

angiosperm fertilization

A

double fertilization!
pollen lands on stigma
recognition –> “germination”
2 nuclei move down a pollen tube to reach the ovary
1 sperm nucleus joins the egg to create the embryo, 1 sperm nucleus joins the polar nuclei to create the endosperm

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25
angiosperm: fruit and flower
``` fruit = modification of ovary wall flower = attracts pollinators ```
26
apical meristem
following embryogenesis, the formation of new cells and tissues becomes restricted to the apical meristem --> zones of high cell activity meristems produce derivatives (cells) which contribute to an increase in length of plant axis - contrast to width root apical meristem and shoot apical meristem new cells: primary b/c they formed at apical meristems and make up primary plant body
27
parenchyma
type of cells 1) alive when functional = have a membrane 2) thin wall 3) participate in repairing wounds 4) participate in photosynthesis 5) sites for storage (eg potato)
28
collenchyma
``` function in support (eg celery) have thick cell walls to distinguish from parenchyma ```
29
sclerenchyma
fibers - act in support, elongated cells which occur in bundles sclereids - act in protection, usually dead when functional, round cells w/ very thick cell walls have a compound (lignin) embedded in cell wall
30
vascular tissue
xylem - functions in water transport, cells are dead when functional (no membrane) phloem - functions in transport of nutrients
31
xylem
tracheids - found in gymnosperms and angiosperms elongated, tapering cells which overlap one another vessel elements - found only in angiosperms very wide, have open end wall
32
phloem
transports nutrients alive when functional (has a membrane) cell type = sieve element
33
stomata
made up of guard cells + pore guard cells - control size of pore pore - allows CO2 in for photosynthesis but also allows H2O to leave
34
root functions
1) anchorage/support of plant 2) storage organ (starch, sometimes sugars) 3) site of absorption of water and minerals 4) symbiotic association with microorganisms
35
roots: eudicots vs monocots
following seed germination - eudicots: primary root (taproot) - grows straight down monocots: primary root is short-lived and gets replaced by finer, netlike roots (fibrous) - no root is dominant
36
root cap
found at the very tip of the root 1) protects root apical meristem 2) produces a lubricant (slime) 3) site of gravity perception in the root
37
gravity perception in roots
statocytes in root cap - starch, bound by a membrane | heavy, helps roots grow downward
38
symplastic vs apoplastic
symplastic - path crosses membranes apoplastic - path includes cell walls and intercellular spaces, no membrane crossing decision to acquire a compound is made at the membrane
39
Casparian strip
made of suberin embedded in cell wall of epidermis water-impervious
40
primary shoot system
stem - nodes, internodes leaves - petiole, blade flowers, fruits - primary tissues (origins traced directly to apical meristem)
41
cross section of the stem: eudicot vs monocot
eudicot - pith (parenchyma cells) at the center, vascular bundles arranged in a ring, phloem toward outside and vessel elements toward inside monocot - no pith, vascular bundles are scattered with no specific xylem or phloem orientation
42
leaf: eudicot vs monocot
eudicot - prominent midvein (vascular tissue), netlike venation monocot - no prominent midvein, usually parallel veins
43
primary growth
extension/elongation of the plant axis as time passes in a eudicot, a new layer of cells extends from the vascular cambium and the xylem and phloem eventually separate
44
vascular cambium
new meristem, makes cells to its inside and outside | needs to enlarge in circumference as it produces new cells to its inside
45
results of secondary growth from vascular cambium (eudicots)
1) primary phloem is pushed to outside 2) primary xylem is pushed to inside 3) new cells produced to inside - secondary xylem (wood) 4) new cells produced to outside - secondary phloem (bark) in woody plants, annual rings will eventually form
46
phototropism
movement in response to light Darwins did experiments on this using the coleoptile of monocot seedlings, decided the coleoptile produced a plant growth regulator that later moved to the zone of growth/elongation
47
auxin
major plant growth regulator 1) apical dominance - due to production of auxin (IAA) at shoot tip - branches do not grow out as much as plant grows up 2) vascular cambium activity 3) fruit development 4) root initiation --> stimulates pericycle 5) leaf fall = abscission (shorter day signals less auxin) 6) plant orientation
48
auxin and plant orientation
if the plant is vertically oriented, there will be a uniform movement of auxin if the plant is horizontally oriented, auxin will stimulate upward elongation at the shoot end but inhibit upward elongation at the root end (root grows down, shoot grows up)
49
gibberellins
``` second major plant growth regulator effects: 1) stimulates cell elongation 2) affects flowering 3) has great commercial use - produces large flowers/fruit 4) controls maturity - juvenile or adult ```
50
gibberellins and seed germination
monocot seed: aleurone layer surrounds endosperm 1) embryo perceives a change in the environment 2) embryo then makes gibberellin 3) gibberellin moves to aleurone layer 4) in aleurone, alpha-amylase produced 5) alpha amylase converts starch to sugar --> germination
51
cytokinins
3rd group of PGRs - cytokinesis (cell division) effects: 1) stimulate cell division 2) delay senescence (aging process) 3) in combination with auxin, can cause organ formation (more cyto and less auxin = shoots, more auxin and less cyto = roots) 4) overcome apical dominance
52
ethylene
gas, 4th group of PGRs effects: 1) promotes fruit ripening 2) autocatalytic (small amount of ethylene causes more to be made) 3) competes with CO2 for an important step in fruit ripening increasing co2 slows the ripening process 4) promotes flowering in certain speices 5) delays flower senescence
53
abscisic acid (ABA)
involved in overcoming stressed if plant is growing in saline conditions - ABA will produce proteins to compensate in seed germination - ABA is in seed coat if it's cold, ABA will gradually breakdown over the cold period until it is used up and the seed germinations --> way of "measuring" length of cold period ABA will be washed out by rain, measures adequate water
54
relevant properties of water molecule
1) polar with regard to charge 2) surface tension 3) evaporates liquid to gas --> hydrogen bonds break depends on temperature and humidity (vapor pressure gradient)
55
mass flow
movement of water from high concentration to low concentration only difference from diffusion is that it is specific to wate
56
diffusion
movement from high to low until distribution is equal (equilibrium)
57
osmosis
diffusion through a selectively permeable membrane of a substance
58
incipient plasmolysis
point when the membrane pulls away from the cell wall occurs because enough water has been removed: turgor pressure decreases, plant wilts at IP, psi-p (turgor pressure) = 0
59
role of the epidermal cell
in order for the guard cells to change turgor (and open/close the pore), potassium moves into/out of the cell from EC if potassium goes into the guard cell, water will go in and turgor pressure will go up if potassium leaves to the EC, water leaves and turgor pressure goes down
60
notes on water potential
psi of pure water is 0 anything dissolved in water will make psi negative psi-p is negative if it is tension (dead/no membrane) and 0 in an open vessel, but positive if it is turgor pressure (alive/membrane) water will move from the less negative to the more negative psi
61
transport in the xylem
water moves from the less negative roots up to the more negative parts of the plant transpiration is the driving force: water leaving the pores is what makes psi negative in the leaves and draws water up from the roots
62
transport in the phloem
1) sugars are moved from the site of photosynthesis into the phloem 2) turgor pressure increases at the region where the sugars are added 3) at the bottom of the phloem, sugars move into storage cells - turgor pressure decreases at the bottom, as water leaves the phloem mass flow of liquid in sieve element
63
mobile nutrients
symptoms show first in older leaves, while younger leaves look good nitrogen, potassium, phosphorus, magnesium
64
immobile nutrients
symptoms show first in younger leaves, while older leaves look good iron, calcium
65
shoot apical meristem during flowering
when a plant transitions to flowering - 1) SAM stops producing leaves 2) SAM enlarges 3) begins to make the organs that comprise the flower
66
ABC model of flowering
``` A, B, C are genes A = sepals A + B = petals B + C = carpels C = stamen ```