Section 2: Plant Biology Flashcards
What are nonvascular plants
plants without a vascular system consisting of xylem and phloem.
Examples of nonvascular plants
Liverworts, hornworts, mosses
what are vascular plants
plant with vascular systems, xylem and phloem (tracheids).
Examples of vascular plants
lycophytes, pteridophytes, cyrads, ginkos, conifers, gymnosperms and angiosperms.
what do lycophytes and pteridophytes have in common
seedless, lignin, roots and leaves, and have tracheids.
what is the difference between lycophytes and pteridophytes
lycophytes: seedless, lignin, roots and leaves, and have tracheids; roots are forked.
Pteridophytes: more vascularized and have branched roots.
What is special about angiosperms
they are the most evolved plant, they have 4 times the amount of vascular systems
how are angiosperms the most evolved
Flowering plants are able to survive in a greater variety of habitats than gymnosperms. Flowering plants mature more quickly than gymnosperms, and produce greater numbers of seeds. The woody tissues of angiosperms are also more complex and specialized.
what does xylem do
transports water
what does phloem do
transports nutrients and minerals
what do angiosperms have that other plants don’t
flowers and fruits
what is the shoot
the stem and the leaves
what is a shoot system
multiple stems and leaves of the same plant
what is a root system
all of the plant’s roots
what does only a plant cell have
cell wall, vacuole, chloroplasts.
what does a cell wall do for a plant
provides a structural framework to support plant growth and acts as the first line of defense when the plant encounters pathogens. The cell wall must also retain some flexibility, such that when subjected to developmental, biotic, or abiotic stimuli it can be rapidly remodeled in response.
what does a chloroplast do?
a plastid: membrane bound organelle.
Chloroplasts have pigments that can absorb light at certain intensities
what does a central vacuole do?
can make 80% of cell volume; usually filled with water; can store calcium, magnesium, pigments, etc. ; used to maintain cell shape.
what does an animal cell only have
lysosomes and centrioles
what is the difference between glycogen and cellulose/starch
glycogen is heavily branched; cellulose/starch have hydroxyl groups.
what shape is amylose
non branched
what shape are amylopectins
branched
what bonds do two starches have
glycosidic linkages
what does pectin do
helps fuse other cells together by attracting negative charges.
Also helps the growth and development of the plant stem.
what is a desmotubule
extension of ER going across plasmodesmata; involved in the lateral transfer of lipid molecules from one cell’s ER to another.
why does a plant need water structurally
to maintain turgidity
what is the middle lamella
a layer that cements together the primary cell walls of two adjoining plant cells. It is the first formed layer to be deposited at the time of cytokinesis. The cell plate that is formed during cell division itself develops into middle lamella or lamellum.
what does the central vacuole do
holds water for structural support and allows cell growth by turgor pressure
what does the auxin hormone do
the master hormone; promotes cell growth and elongation of the plant. In the elongation process, auxin alters the plant wall plasticity making it easier for the plant to grow upwards. Auxin also influences rooting formations.
what do cytokinin hormones do
promote cytokinesis
what do gibberellin hormones do?
promotes seed germination, root and shoot elongation, flowering, and fruit patterning; important for cell division and stem cell regulation.
what do microfibrils do
give plant cells its shape. Formed in stacks which allows the cell wall inside to grow a certain way; can grow up and down, sideways.
what is the meristem
are centers of mitotic cell division, and are composed of a group of undifferentiated self-renewing stem cells from which most plant structures arise. Meristematic cells are also responsible for keeping the plant growing.
what is the apical meristem
region of cells capable of division and growth in the root and shoot tips in plants. Apical meristems give rise to the primary plant body and are responsible for the extension of the roots and shoots.
what is dermal tissue
the covering on various plant parts (outside)
what is ground tissue
most of the plant’s body with a variety of functions (metabolically active tissue).
what is vascular tissue
form interconnected conducting vessels for water and nutrients.
what is the cortex of the plant
tissue of unspecialized cells lying between the epidermis (surface cells) and the vascular, or conducting, tissues of stems and roots.
what are the main organs of the plant
stem, root, leaves
what do all multicellular organisms do
carry out cell division, grow, differentiate/cell specialization, apoptosis
what might happen when a meristem cell divides?
one daughter cell might receive a protein signal to remain a meristem cell. The other daughter cell might go on to be ground or dermal cells.
what is the shoot apical meristem (SAM)
stem cells that continuously generates organs and tissues.
what is the root apical meristem (RAM)
a small region at the tip of a root in which all cells are capable of repeated division and from which all primary root tissues are derived (root growth source)
what is the protein SAM uses
wus
what is the protein RAM uses
wox
what is parenchyma
a type of simple permanent tissue that makes a major part of ground tissues in plants, where other tissues like vascular tissues are embedded. They are non-vascular and composed of simple, living and undifferentiated cells, which are modified to perform various functions.
what is collenchyma
a simple plant tissue, consisting of only one cell type. Collenchyma cells are elongated, living cells that occur especially in peripheral positions in leaves and stems of eudicotyledons where they provide mechanical support while they are still growing.
what is sclerenchyma
provide mechanical support and strength to the plants. They provide structural support to the plant organs. They form protective coverings around nuts and seeds. They are also a part of vascular bundles and form conductive tissues
what is a vascular bundle
a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. transporting nutrients, growth signals, amino acids, and proteins between aerial and underground tissues.
what is a palisade
a layer of closely packed cells found under the upper epidermis and cuticle which is the outermost layer of a leaf. The definition of palisade is a layer of plant cells containing chloroplasts right below the cuticle and upper epidermis in plants. Palisade cells are columnar shaped.
what is spongy parenchyma
a spongy layer of irregular chlorophyll-bearing cells interspersed with air spaces that fills the interior part of a leaf below the palisade layer.
what are eudicots
angiosperms that have two seed leaves upon germination
how is the vascular tissue arranged in eudicots
ring arrangement
what are monocots
angiosperm which typically contain only one embryonic leaf, or cotyledon.
how is the vascular system arranged in a monocot
random vascular tissue throughout
what are leaf primordia
first leaves of a plant
what happens to monocots’ first leaves
they lose them
what do eudicots do with their first leaves
preserve them
What do primary meristems give rise to
secondary meristems
why is the upper portion of the leaf thicker and the cuticle waxy?
to protect itself from UV exposure
what are herbaceous plants
vascular plants that have no persistent woody stems above ground.
what are woody plants
woody texture that have secondary growth
what do eudicots stem with
a single leaf and primate venation (main veins that radiate from base of the leaf).
what is pinnate venation
when there is a main vein in the middle of the leaf and several branches.
how do monocots stem?
they stem and leaf with parallel venation (only main veins going one direction)
what can compound leaves do?
survive in extreme heat because of the smaller leaves that are in abundance
what is the cuticle of the leaf
on epidermis helps avoid desiccation.
Filters UV radiation, reduce microbe and animal attacks, self cleaning,
Waxy texture.
what are trichomes
offer protection from excessive light, ultraviolet radiation, extreme air temperature, or attack by herbivores.
Can comes in various shapes and states with stem and leaves,
Filled with secondary metabolites (poison), secreted or stored.
what are phytoalexins
low molecular weight antimicrobial compounds that are produced by plants as a response to biotic and abiotic stresses.
what are guard cells
regulate stomatal opening and closing for water, oxygen, and carbon dioxide.
what do leaves most do for the plant
photosynthesis
what are other leaf shapes plants can have
Tendrils
Tough scales that protect buds
Poinsettia “petals”
Cactus spines
what is primary xylem
the xylem that is formed during the primary growth from procambium of apical meristems.
what is primary xylem made of
Unspecialized parenchyma cells.
what do tracheids and vessel elements do
conduct water and dissolved minerals (not living cells).
properties of tracheids
Tracheid xylem is dead, but extremely tough and acts like structure support.
Tracheids are small and vessel elements are large.
what can happen to vessel elements
they can get embolisms, especially in the wintertime
what is guttation
release embolism from vessels with water.
what is primary phloem
a type of phloem that forms from the procambium during the primary growth. The primary growth is responsible for the growth in length in plants.
what is the procambium
a meristematic tissue that enables the primary growth of a plant.
what is the main function of primary phloem
Transports organic compounds and certain minerals.
Cells are alive unlike xylem.
what is the primary phloem made up of
living sieve tube elements and companion cells that aid sieve tube elements metabolize
what are supportive fibers in primary phloem
long sclerenchyma that runs along sieve-tube elements that provide protection and aid in packaging
what are created by the companion cells
P protein and P protein RNA
what do P proteins do
clot tubes if there is damage
why does wood have tracheids
for water support
what do resin ducts do
resin helps prevent attack by pathogens and herbivores.
how does water and nutrients get passed 100 meters
capillary action; xylem and phloem work together
what is transmembrane transport
involves proteins that will physically take whatever the plant needs and carry it through the root cells (ATP).
what is symplastic transport
through the plasmodesmata
what is apoplastic transport
water and minerals can go through cell walls of the layers on cells in roots; diffusion of water and minerals between cells.
what is the casparian strip
a waxy, ribbon-like compound made out of phenol polymers and suborin; form a barrier to the apoplastic flux, forcing ions to pass through the selectively permeable plasma membrane into the cytoplasm, rather than move along the cell wall.
what is the pith
a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which in some cases can store starch.
what is wood composed of
all xylem
what is the vascular cambium
a layer of meristematic cells (or initials) that arises between primary xylem and phloem;gives rise to secondary meristems, which give rise to xylems.
what is the cork cambium
gives rise to secondary meristem, which gives rise to the phloem.
what are the percent makeup of wood
25% lignin, 50% cellulose, 25% other types of polymers
what kind of roots to eudicots have
taproots
what are taproots
a main root that has little roots growing off.
Taproots are constructed in a way to anchor themselves.
what kind of roots to monocots have
branched; no main root and random
what is a quiescent cell
a cell that doesn’t grow but is still alive; acts like a barrier between downward growing cells and vascular cells.
what are root caps
tip of the root that produces mucilage; made of parenchyma
what are root hairs
long but thin hairs that stem from the root that absorb water and nutrients
what are stem nodes
tissue that gives rise to the leaves
what are internodes
area between the nodes; represent how much the plant has grown; indicate how large the plant might get.
what are auxiliary meristems
tissues that produce branches and flowers
what does the axil determine
the direction/angle of growth
where does the auxin hormone come from
secreted by epidermal layer; meristem follows in layers
where is the gibberellic acid hormone from
produced by the SAM; promotes cell division and growth
do eudicots have petals or tepals
petals
do monocots have petals or tepals
tepals
how many petals do eudicots
4 or 5 (and combos of those numbers)
how many tepals do monocots have
3 or combos of 3
what are the male flower components
a stamen composed of an anther (sporangia) and filament
how is pollen formed
Diploid cell undergoes meiosis, turning 1 cell to 4, and creates haploid microspores, which undergo a little bit of mitosis and give rise to pollen.
what is pollen typically
a gametophyte
what is a generative cell
a cell within the pollen spore that will divide into two cells to form sperm
what is the pollen spore structure
pollen coat, cytoplasm, generative cell, nucleus, tube cell.
what is the filament
vascular tissue that supplies nutrients from sporophyte (plant) through development of the anthers.
what is the female pistil composed of
stigma, style, and ovary
what does the ovary house
the ovules, 1 or more in ovary
what is the sporangia tissue of female flowers
the ovules
how is the female sporangia formed
A diploid cell undergoes meiosis, creating 4 haploid cells, but 3 cells die off and 1 cell undergoes mitosis and becomes a 7 cell gametophyte.
what do the 7 cells do
One of the 7 cells is the egg, the cells surrounding the egg are synergistic cells, the other 3 are antipodal cells. The megaspore that holds the 7 cells have 2 nuclei called bilobed nuclei.
what is the microphyte
entrance for the tube cell to the megaspore
what is self pollination
when the pollen lands on the same plant’s stigma
what is cross pollination
when pollen of one plant land on another plant’s stigma
what happens if the s proteins are on the inside and match the genotypes of the ovules
the pollen will try to grow but RNAse will chop up the growth.
what happens if the s proteins are on the outside and match the genotypes of ovules
s proteins on the stigma will immediately stop pollen growth.
when is are the spores compatible
if the 4 genotypes don’t match (2 to 4 and 3 to 1)
what does the pollen coat do
allows growth and fertilization; protection
what does the tube cell do
will grow from the pollen sporophyte into the stigma, where it will work its way down to the ovary. The nucleus and the generative cells will be transported down the tube, they are now called sperm.
how is the seed formed if spores are compatible
When one of the sperm reaches the egg through the micropyle, the embryo will turn to a zygote after undergoing mitosis. Alternation of generations will occur. The second sperm (the endosperm) will make up the nutritional tissue for the zygote. The embryo and the endosperm is referred to as the seed. (Double fertilization).
what is the ovary called when filled with seeds
fruit
what are the three mechanisms of pollination
wind, insects/animals, rain/watering
why are the seed undergo a drying process
to stop metabolism until seed/embryo reaches the right environment
what is the radicle
the first organ to appear when a seed germinates. It grows downward into the soil, anchoring the seedling.
what is the cotyledon
seed leaf within the embryo of a seed. Cotyledons help supply the nutrition a plant embryo needs to germinate and become established as a photosynthetic organism and may themselves be a source of nutritional reserves or may aid the embryo in metabolizing nutrition stored elsewhere in the seed.
what are plastids
double-membrane organelles which are found in the cells of plants and algae; green
what are protoplasts
isolated cells devoid of the cell wall.
what are chromoplasts
Like plastids but have carotenoids and lack chlorophyll. Carotenoid pigments are responsible for different colours like yellow, orange and red colour
what are leucoplasts
a colorless organelle found in plant cells, used for the storage of starch or oil.
what stimuli do all plants respond to
light, gravity, water, movement of the sun, and touch.
what is abscisic acid
It promotes the dormancy in seeds and buds.
how is auxin transported
down to the root tip from the shoot in the vascular cylinder. Here it is redistributed to the root cortex and epidermis, and transported back up the root to the elongation zone, where it regulates the rate of cell elongation.
what ancestral feature is retained in cycads and gingkoes; what are the constraints.
motile sperm with flagella; the plants need a lot of water in order to allow sperm to swim.
why did the seed evolve
they are better at helping plants to survive than spores are. For example, seeds contain a food source to help the new plant grow.
what are key innovations in plant evolution?
the increasing dominance of the sporophyte; green algae still have a dominant gametophyte
what are vascular seedless plants
plants that contain vascular tissue, but do not produce flowers or seeds. In seedless vascular plants, such as ferns and horsetails, the plants reproduce using haploid, unicellular spores instead of seeds.
how can plants refill embolized vessels
re-route water through nearby xylem, create new xylem or refill vessels to force the air bubbles to dissolve in water
why are vessel elements prone to embolism
if the tension in the xylem conduits becomes too high, thus xylem cavitation can occur i.e., water column breakage. This results in the hydraulic disconnection of leaves and above-ground parts from roots because xylem conduits are filled with air and water vapor
what is the cohesion-tension theory of water transport
The water ascent in trees is exclusively due to the transpirational pull from continuous water columns in the xylem conduit running from the roots to the leafs.
what is the relationship between sieve tube cells and companion cells
Companion cells are associated with sieve elements through plasmodesmata and they together help in the transport mechanism in plants.
why do land plants do alternation of generations
alternation of generations still allows sexual reproduction to occur. This greatly mixes the genes and increases the adaptability of the species. Sporophytes and gametophytes from different species also produce different types of spores and gametes.
what is the sepal of a flower
green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom.
what is the carpels of a flower
the ovule-bearing female reproductive organ of flowering plants
what is the microsporangia
sporangia that produce microspores that give rise to male gametophytes when they germinate.
what is the megasporangia
the structure of a plant body which contains female reproductive organ . It can be called ovule . It consists of nucellus and integument .
what is double fertilization
involves two sperm cells; one fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei that form the endosperm. After fertilization, the fertilized ovule forms the seed while the tissues of the ovary become the fruit.
what does the polar nuclei do
after an act of double fertilization forms triploid nutritive tissue called endosperm.
what tissues make the seed coat
develops from sporophyte tissues of the parent plant that are called integuments, one or several layers of sporophyte tissue that form the outer layers of the ovule.
what is the hypocotyl
the part of the stem of an embryo plant beneath the stalks of the seed leaves or cotyledons and directly above the root.
what is apical-basal polarity
a specialised apical membrane facing the outside of the body or lumen of internal cavities, and a specialised basolateral membrane localised at the opposite side, away from the lumen.
what is a protoderm
a thin outer layer of the meristem in embryos and growing points of roots and stems, which gives rise to the epidermis.
