Chapter Ten: Plants Flashcards
Plants include all multicelled, eukaryotic, photosynthetic _
Autotrophs
Plant cell walls are made of _ and they store carbs as _
Cellulose
Starch
State characteristics of bryophytes
vascular tissue, habitat and why and water absorption, size and why
They have no vascular tissue
Live in moist environment because they have no xylem/roots so absorb/transport water by osmosis
They are small because they lack lignin-fortified tissue that support tall plants on land
State characteristics of tracheophytes
transport vessels, reproduction
Have xylem and phloem
Both seedless/spores and seeds
What are gymosperms?
They are conifers, cone-bearing plants with seeds on the surface
Some ways conifers are made resistant to wind/cold/drought
W-needle shaped leaves
C-thick waxy cuticle
D-stomates in stomatical crypts to reduce further water loss
What are angiosperms?
Flowering plants in which seeds develop inside ovaries of flowers. Ovary becomes fruit
Angiosperms are divided into monocots and dicots. State differences (cotyledons, vascular bundles, leaf venation, floral parts, roots)
Mono-1 baby seed leaf, scattered bundles, parallel, in 3s, fibrous root system
Di-2 baby seed leaves, branched network, 4s or 5s, tap root system
What is a cladogram?
Shows evolutionary relationships with development of traits
What were the 3 biggest problems plants faced as they moved to land as competition increased in water?
- suporting a plant body
- absorbing water
- conserving water
How do plants have support?
Cellulose cell walls to maintain shape
How do plants absorb water from the soil?
Roots and root hairs
What are the functions of stomates?
- open to exchange photosynthetic gases
- cloee to minimize excessive water loss
Apart from stomata, what else helps plants with reducing excessive water loss?
Waxy cuticle made of cutin
What is gametangia?
Protective jacket of cells in some plants which prevent gametes and zygotes from drying out
What is sporopollenin and wheres it found?
It is a tough polymer resistant to most environmental damage Ian’s protects plants in harsh terrestrial places.
Found in cell walls of spores and pollen
Seeds and pollen have a protective coats that prevents _ and allows for _
Desiccation (drying out)
Dispersal
Why do plants continue to grow as long as they live?
They have meristem tissue that continually divides
What is primary growth?
It is vertical growth, elongation of the plant down into the soil and up into the air
New cells arise from _ in primary growth. These are located _ and _
Apical meristem
Buds if shoots tips of roots
3 zones of cells at different stages of primary growth at the root + root cap?
Zone of cell division - apical meristem
Zone of elongation
Zone of differentiation/specialization - root hairs
Root cap - secretes substance to digest earth as the root grows through soil
The zone of division has _ which are activly dividing
Meristem
Cells in in zone of elongation are responsible for?
Pushing the root cap downward and deeper
One the zone of specialization cells undergo specialization into 3 primary meristems that give rise to 3 tissue systems. These are:
Epidermis
Ground tissue
Xylem phloem
What is secondary growth?
Lateral growth or an increase in girth
What makes secondary growth possible?
Layers meristem
Why is it that herbaceous plants don’t have secondary growth?
They only live for 1 season
Functions of the roots:
- absorb nutrients from soil
- anchor plant to soil
- store food
What is the epidermis in roots?
Covers the root surface, and has slender cytoplasmic projections from epidermal cells called root hairs which extend and increase roots absorptive surface area
What is another name for vascular cylinder and it’s function?
Stele
Support
State structure of a stele
Has vascular tissue surrounded by 1/+ layers of pericycle tissue, from which lateral roots arise
What is endodermis?
Tightly packed layer of cells around the stele
Each endoderm cell is wrapped with a casparian strip. What is this?
A continuous band of waxy material, impervious to water and dissolved minerals
Function of endodermis?
Select what minerals enter stele and body of plant
What is lateral movement?
Movement of water and solutes across a plant
What is symplast?
Continuous system of cytoplasm of cells interconnected by plasmodesmata
What is apoplast?
Network of cell walls and intracellular spaces within a plant body that permit extensive extracellular movement of water within the plant
Mature plants lack root hairs they have mycorrhizae. What are mycorrhizae?
Symbiotic structures consisting of plant roots intermingled with hyphae (filaments) of fungus that increase absorption quantity of nutrients
What is rhizobium?
Symbiotic bacterium that lives in root nodules and fixed nitrogen gas into another form the legume needs
What is a tap root?
Single large dominant root that gives rise to lateral branch roots. Some plants are modified to use it for storage
What is a fibrous root system?
Thin branching roots from the stem. Holds the plant firmly in place and thus minimize soil erosion
What are adventitious roots?
Rise above ground
What are aerial roots?
Trees growing in swamps/marshes have these roots sticking up out of the water and aerate the root cells
What are prop roots?
Eg corn have roots that grow aboveground our from the base of the stem and help support the plant
What’s the function of the stem and how does this help the leaves? Also give an an auxiliary function of stems
Support
Allows leaves to receive the most light
Transport water and minerals from the soil, and nutrients from leaves to the rest of the plant
What are Vascular bundles?
Strands of vascular tissue
What does a vascular bundle contain?
Xylem on the inside
Phloem outside
Meristem tissue between the two - cambium
How are vascular bundles arranged in monocot and dicots in STEMS?
mono- scattered through out (mainly edge)
di- ring around the edge
How are vascular bundles arranged in monocot and dicots in ROOTS?
mono- ring
di- xylem in the center and phloem outside the xylem
What is ground tissue? What does it consist of in the stem?
Theground tissueof plants includes all tissues that are neitherdermalnorvascular.
Cortex, pith, and parenchymal tissues modified for storage
What is pith?
Pith is composed of soft, spongy, meristematic parenchymacells, which store and transport nutrients throughout the plant
How is the leaf organized?
Maximise sugar production
Minimize water loss
Function of upper/lower epidermis?
Protection
Function of waxy cuticle?
Minimizes water loss
Function of guard cells (modified epidermal cellsc, contain chloroplasts)
Control opening/closing of stomates
Function of Palisade mesophyll?
(Tightly packed)
Photosynthesis
Function of spongy mesophyll?
(loosely packed)
Photosynthesis
Diffusion and exchange of gases
Function of veins (in the mesophyll)?
Carry water and nutrients from soil to leaves, and sugar from leaves to the rest of the plant
Respiration needs 1 and produces 2
Photosynthesis needs 3 and produces 4
1- o2
2- co2
3- co2
4- 02
Why and when (in the day) do stomates open and close ?
They open to allow gas exchange and close to reduce water loss by transpiration.
They open when photosynthesis is running at stop speed when the sun is bright, and close at night
How do stomates open and close?
They do in response to water pressure. Become turgid and open, flaccid and close
4 types of plant tissues?
Dermal
Vascular
Ground
Meristem
What is dermal tissue?
Outer protective covering with a single layer of epidermal cells
2 ways epidermal cells are protected?
Waxy Cuticle
Spikes called trichomes
How are stomates, as epidermal cells, different from other ones?
Have chloroplasts
What’s vascular tissue?
Transport water and nutrients
What is ground tissue
Make up all plant tissue except dermal and vascular
3 ground tissue types?
Parenchyma
Collenchyma
Sclerenchyma
How do parenchyma cells look
Primary thin flexible cell wall (no secondary wall)
1/2 large vacuoles that supports the plant when turgid
Eg chlorplasts in mesophyll cells
How do collenchyma cells look
Unevenly thickened primary cell walls
No secondary cell wall
How do sclerenchyma cells look
Very thick primary and secondary cell walls fortified with lignin
Function: support
2 types of elongated cells consisting xylem?
Tracheids (secondary cell wall of lignin for support and transport)
Vessel elements
How do xylem carry water/nutrients up? (4 points)
Against gravity
Without expenditure of energy
Trnaspirational pull
Cohesion tension
What are transpiration and cohesion?
T- evaporation from leaves
C- water molecules attracted to eachother
What does the transpirational pull-cohesion tension theory state?
For each molecule of water that evaporates by transpiration (due to sunlight), another is drawn at the root to replace it
4 factors affecting rate of transpiration :
1) Humidity: high/slow, low/fast
2) Wind: reduce humidity near stomates thereby increase transpiration
3) Light intensity: more heat, increased photosynthesis and more water vapour to be transpired
4) Closing stomates: stop transpiration
Phloem are made of chains of _ and _
Sieve tube elements
Companion cells
What is translocation?
Process by which phloem carry sugar from leaves to rest of plant and requires Energy
How do plants reproduce asexually?
Vegetative propagation where a vegetative piece of a plant reproduces an entirely new plant identical to the parent
State the structure and function of petals
Brightly colored
Modified leave found inside the sepals
Attract pollinators
State the structure and function of sepals
Outermost circle of leaves
Green
Enclose the bud and protect it and then the flower as it develops
State the structure and function of pistil/carpel
Ovary, stigma, style
Produce female gametophytes
State the structure and function of ovary
Swollen part of carpel
Contains ovule where Ova produced by meiosis
State the structure and function of ovule
In ovary where ova are produced
State the structure and function of style
Long stalk of carpel
State the structure and function of stigma
Sticky top of style when pollen lands
State the structure and function of stamen
Male part
Anther+filament
State the structure and function of anther
Pollen produced by meiosis
State the structure and function of filament
Threadlike structure supporting anther
State the nuclei of pollen
3 haploid nuclei-1 tube nucleus, 2 sperm nuclei
Explain pollination and double fertilization in flowering plants
When pollen lands on stigma, absorbs moisture and germinates/sprouts a pollen tube that burrows down the style. 2 sperm nuclei go through the tube to ovary, and then through a micropyle into ovule. One sperm fertilizes egg to form embryo (2n). The other fertilizes 2 polar bodies and becomes triploid (3n) endosperm or cotyledon (food for embryo)
What is a polar body?
Small haploid cell that is formed concomitantly as an egg cell during oogenesis, but generally does not have the ability to be fertilized. When certain diploid cells in animals undergo cytokinesis after meiosis to produce egg cells, they sometimes divide unevenly.
Ovule becomes _ and ripened ovary becomes _
Seed
Fruit
What is endosperm?
nutritivetissueinseedplantsformedwithintheembryosac bydivisionof theendospermnucleus
What is a cotelydon
thefirst/embryonicleafor one of thefirstpair
State how food reserves differ between monocot and dicots?
M- remain in endosperm
D- transported to cotyledons
State the 2 equations of double fertilization
- Sperm+ovum->embryo(2n)
2. Sperm+2 polar bodies->endosperm(3n)
What does a seed consist of?
Protective seed coat
Embryo
Cotyledons/Endosperm
What does embryo consist of
Hypocotyl - lower part of stem and roots
Epicotyl - upper part of stem
Radicle - embryonic root
Differences between monocot and dicot seeds?
Dicot can be spilt in half
Dicot has cotyledons monocot has endosperm
The gametophyte generation is
Haploid n
The sporophyte generation is
Diploid 2n
Briefly explain how sexually reproducing plants alternate between generations
The haploid gametophyte produces gametes by mitosis. These fuse during fertilization to yield diploid zygotes. Each zygote produces sporophytes by mitosis , which by meiosis give haploid spores. Then these form gametophytes by mitosis. And the cycle continues
What is antheridium?
Produces sperm, develops of gametophyte
What is archegonium
Produces eggs, develops on gametophyte
What is gametophyte
Haploid adult plant
What is a megaspore
Produced by large female cones and develop into female gametophytes
What are microspores
Produced by small male cones and develop into male gametophytes or pollen
What is protonema
Branching, one cell thick filaments produced by germinating moss spores, become gametophyte in moss
What is sporangia
On tip of mature sporophytes where meiosis occurs producing haploid spores
What is sporophyte
Diploid adult plant
What is sori
Raised spots underside sporophyte ferns, clusters of sporangia
What is sori
Raised spots underside sporophyte ferns, clusters of sporangia
Plant hormones help coordinate _, _ and _ to environmental stimuli
Growth
Development
Response
Why do phototropisms occur
Due to unequal auxin distribution
Auxin enhance apical dominance. What does this mean
Growth of plant upward rather than laterally. Terminal bud depresses lateral growth by suppressing development of axial buds
How do auxin stimulation stem elongation and growth
By softening cell walls
What is IIA
Naturally covering auxin
Indoleacetic acid
What are cytokinins
Hormones that stimulate cytokinesis and cell division Delay aging (senescence) by inhibiting protein breakdown
What do gibberellins do (hormones)
Promote stem and leaf elongation
What is bolting and why is it important
Rapid growth of floral stalk in the reproductive stage to ensure pollination and seed dispersal
What does abscisic acid do (hormone)
-ABA inhibits growth and printed seed dormancy
Eg Withstand drought
-Closes stomates during times of water stress
What is ethylene
Gaseous Plant hormone
What are auxins
Hormones
What does ethylene do
Promotes ripening
What is a tropism
Growth of a plant towards or away from a stimulus
State 3 tropisms
Thigmo (touch)
Geo/gravi
Photo (light)
Toward a stimulus is a _ tropism while away is _
Positive
Negative
What generation dominates in moss. What does this mean
Gametophyte
Most of life cycle and sporophyte depend on ^ for nutrients which is gets by photosynthesis
What is moss
Green carpet like plan in damp forests
What are ferns
Seedless vascular plants intermediate of primitive bryophytes and vascular flowering plants
Which generation is dominant in ferns and how does the dependancy work
Sporophyte
However both g and s sustain themselves by photosynthesis
What are seed plants
Vascular seed producing plants
What generations do angiosperms depends on
Sporophyte
In gymosperms (conifers/cones) how do gametophytes form
Gametophyte develops from haploid spores retained in sporangia
