Shared Flashcard Set

Details

Botany Comprehensive Exam
Fall 2012
252
Biology
Graduate
07/04/2012

Additional Biology Flashcards

 


 

Cards

Term
Chlorobium chlorophyll
Definition
Primary pigment in green sulfur bacteria
Term
Bacteriochlorophyll
Definition
Primary pigment in purple bacteria
Term
Phycobilins
Definition
Water soluble accessory pigments in red algae and cyanobacteria
Term
Restriction enzymes (HindII, EcoRI)
Definition
Cut double stranded DNA at specific recognition sequences
Term
Taq polymerase
Definition
Temperature-resistant DNA polymerase used in PCR
Term
Centromere
Definition
Region of chromosome that holds the sister chromatids together
Term
Mitotic spindle
Definition
Widest in the center and tapers towards the ends; appears in the area formerly occupied by the nucleus
Term
Spindle fibers
Definition
Bundles of microtubules
Term
Kinetochores
Definition
Specialized protein complexes that develop on each centromere; spindle fibers attach here during mitosis and meiosis
Term
Daughter chromosomes
Definition
After anaphase the two sister chromatids are separated and called daughter chromosomes
Term
Motor proteins
Definition
Use ATP to pull the chromosomes along the microtubules to the poles while tubulin subunits are simultaneously lost at the kinetochore (i.e. dynein or kinesin)
Term
Phragmoplast
Definition
Barrel shaped system of microtubules that form between the two daughter cells
Term
Synapsis
Definition
The pairing of homologous chromosomes
Term
Bivalents
Definition
The associated pairs of homologous chromosomes
Term
Chiasma
Definition
The "X" configuration that is visible evidence that crossing-over has occured
Term
Totipotence
Definition
The power of regeneration
Term
Suspensor
Definition
A structure at the base of the embryo in many vascular plants; it may push the embryo into a nutrient-rich tissue of the female gametophyte
Term
Protoderm
Definition
Precursor to epidermis
Term
Ground Meristem
Definition
Precursor to the ground tissue
Term
Procambium
Definition
Precursor to the vascular tissues (xylem and phloem)
Term
Funiculus
Definition
The stalk that connects the ovule to the ovary wall
Term
Epicotyl
Definition
The upper portion of the axis of an embryo or seedling, above the cotyledons and below the next leaf or leaves
Term
Plumule
Definition
The first bud
Term
Hypocotyl
Definition
The stemlike axis below the cotyledon
Term
Radicle
Definition
Embryonic root at the base of the hypocotyl
Term
Radicle
Definition
Embryonic root at the base of the hypocotyl
Term
Scutellum
Definition
Grass cotyledon
Term
Coleoptile
Definition
Grass' sheathlike protective structure that encloses the radicle and plumule
Term
Hilum
Definition
Scar on the seed coat caused by the removal of the funiculus
Term
Epigenous
Definition
Germination in which the cotyledons are carried above ground
Term
Stomatal transpiration (2 steps)
Definition
(1) Evaporation of H2O from cell wall surfaces bordering the intercellular spaces of the leaf, and (2) diffusion of the resultant H2O vapor from the intercellular spaces into the atmosphere via the stomata
Term
Radial micellation
Definition
These allow the guard cells to lengthen while preventing them from expanding laterally
Term
Environmental factors affecting stomatal movement
Definition
CO2 concentration, light, and temperature
Term
How does temperature affect the rate of transpiration
Definition
Rate of H2O evaporation doubles for every 10 degree C rise
Term
Cavitation
Definition
A rupture of the water columns
Term
How does humidity affect the rate of transpiration
Definition
Rate of transpiration is proportional to the vapor pressure difference
Term
How do air currents affect the rate of transpiration
Definition
Wind blows away the water vapor from leaf surfaces, affecting the vapor pressure difference across the surface. Sometimes, the air is very humid, wind may decrease transpiration by cooling the leaf, but a dry breeze will greatly increase evaporation
Term
Tropism
Definition
Directional growth in response to an external stimulus
Term
Embolism
Definition
Occurs after cavitation and is the filling of vessels and/or tracheids with air or water vapor
Term
Air seeding
Definition
Occurs only when the pressure difference across the wall or pit membrane exceeds the surface tension at the air-water meniscus spanning the pores
Term
Apoplastic water movement
Definition
Occurs via cell walls
Term
Symplastic water movement
Definition
From protoplast to protoplast via plasmodesmata
Term
Transcellular water movement
Definition
From cell to cell, with water moving from vacuole to vacuole
Term
Guttation
Definition
The exudation of liquid water from leaves, which is caused by root pressure
Term
Hydathodes
Definition
Location where water is exuded from the leaves
Term
Hydraulic lift
Definition
Water taken up at night by deep roots located in moist soil regions is transferred to dry soil regions via shallower roots
Term
The major pathway followed by ions from the epidermis to the endodermis of the root
Definition
Symplastic
Term
Active ion transport from the soil to the vessels of the xylem requires two carrier-mediated membrane events
Definition
(1) uptake at the plasma membrane of the epidermal cells, and (2) secretion into the vessels at the plasma membrane if the parenchyma cells bordering the vessels
Term
Essential elements for plant growth (17)
Definition

C, H, O, K, Ca, Mg, N, P, S, Fe, Mn, Zn, Cu, Cl, Bo, Mo, Ni

First 8 are micronutrients and last 9 macronutrients

Term
Two primary criteria by which an element is judged to be essential
Definition
(1) If it is needed to complete the life cycle, and (2) if it is part of any molecule that is necessary for life
Term
Necrosis
Definition
Exhibit symptoms such as stunted growth of stems and leaves, localized death of tissues
Term
Phototropism
Definition
Growth of shoot tips towards light under the influence of the hormone auxin
Term
Thigmotropism
Definition
A response from contact with a solid object. Cells touching the support shorten slightly, and those on the other side elongate
Term
Photoperiodism
Definition
Biological response to a change in the proportions of light and dark in a 24-hour daily cycle. Effect of daylength on flowering discovered by W.W. Garner and H.A. Allard 75 years ago
Term
In 1959, Harry A. Borthwick
Definition
Named a photoreceptor phytochrome
Term
Thigmomorphogenesis
Definition
altering growth patterns and generalized effects of mechanical stimuli on plant growth and development
Term
Heliotropism
Definition
ability for leaves and flowers of many plants to move diurnally, orienting themselves either perpendicular or parallel to the sun's direct rays. Not a result of asymmetrical growth. Movements involve pulvini
Term
Secondary growth results from the activity of
Definition
two lateral meristems: the vascular cambium and the cork cambium
Term
Resin ducts
Definition
Relatively large intercellular spaces lined with thin-walled parenchyma cells that secrete resin into the duct
Term
Tyloses
Definition
Are formed in the vessels when they become nonfunctional; they are baloon-like outgrowths from ray or axial parenchyma cells through pit cavities in the vessel wall
Term
rootcap
Definition
A thimble-like mass of living parenchyma cells that protects the apical meristem
Term
Embryogenesis
Definition
Development of an embryo from a fertilized egg, or zygote
Term
Apical Meristems
Definition
Found at the tips of all roots and stems and are involved primarily with extension of the plant body.
Term
Initials
Definition
The cells that maintain the meristem--the cells that perpetuate the meristem
Term
The primary meristems
Definition
protoderm, procambium, and ground meristem. These are extended through the plant body by the activity of apical meristem.
Term
Development
Definition
The sum total of events that progressively form an organism's body--involves 3 overlapping processes: growth, morphogenesis, and differentiation. The specific development pathway followed is detemined by environmental factors.
Term
Morphogenesis
Definition
During development a plant assumes a particular shape or form
Term
Differentiation
Definition
The process by which cells with identical genetic constitutions become different from one another and from the meristematic cells from which they originated. Cellular differentiation depends upon the control of gene expression.
Term
Epigeous
Definition
Type of seed germination in which cotyledons are carried above ground.
Term
Hypogeous
Definition
The type of seed germination in which the cotyledons remain underground.
Term
Column
Definition
One stamen present that is fused with the style and stigma into a single structure
Term
Pollinium
Definition
The entire contents of an anther are held together and dispersed as a unit
Term
Flavonoids
Definition
The most important pigments in floral coloration.
Term
Phototropins 1 & 2
Definition
Flavoproteins identified as the photoreceptors for blue light signaling pathways in Arabidopsis
Term
Chromophore
Definition
The light absorbing portion of the phytochrome molecule
Term
Etiolated
Definition
A condition with increased stem elongation, poor leaf development, and a lack of chlorophyll; found in plants growing in the dark
Term
Stratification
Definition
The process of exposing seeds to low temperatures for an extended period of time before attempting to germinate them at warm temperatures
Term
Scarification
Definition
The process of cutting or softening a seed coat to hasten germination
Term
Vernalization
Definition
The induction of flowering by cold treatment
Term
Hormone involved in phototropism
Definition
Auxin
Term
Hormones involved in gravitropism
Definition
Auxin and cytokinin (in roots)
Term
Starch-statolith hypothesis
Definition

Sedimentable amyloplasts in shoots/columella act as gravity sensors

 

Term
Protoplast pressure hypothesis
Definition
Weight of entire protoplast determines gravity perception
Term
Tensegrity Model
Definition

Refers to the structural integrity created by interactive tension between structural components;

amyloplasts create tension on actin filaments, increasing cytosolic Ca2+

Term
Parthenocarpic fruits
Definition
Fruits that may develop without seed formation
Term
Simple Fruits
Definition
Fruits develop from one carpel or from several united carpels
Term
Aggregate Fruits
Definition
Fruits that consist of a number of separate carpels of one gynoecium; composed of fruitlets
Term
Multiple Fruits
Definition
Consist of the gynoecia of more than one flower
Term
Haustoria
Definition
Specialized absorptive organs of parasitic flowering plants
Term
Saprophytes
Definition
Plants that obtain their nutrition from decaying organic matter
Term
Anthophyta
Definition
Refer collectively to the Bennettiales, gnetophytes, and angiosperms
Term
The earliest known fossils of angiosperms
Definition
Flowers and pollen grains up to 130 million years old, from the Early Cretaceous period
Term
Bennettitales and gnetophytes first appear in the fossil record in...
Definition
the Triassic period, about 225 million years ago
Term
The perianth of early angiosperms
Definition
did not have distinct sepals and petals
Term
First alkaloid to be identified in 1806
Definition
Morphine from the opium poppy
Term
Tannins
Definition
Probably the most important deterrent to herbivore feeding in angiosoerms, phenolic compounds present in relatively high concentrations in the leaves
Term
Cell theory formulated
Definition
early in the 19th century
Term
Cell theory states
Definition
(1) all living organisms are composed of one or more cells, (2) the chemical reactions take place within the cells, (3) cells arise from other cells, (4) hereditary information is passed from parent to daughter cells
Term
The plasma membrane has several important functions
Definition
(1) It mediates the transport of substances into and out of the protoplast, (2) it coordinates the synthesis and assembly of cell wall microfibrils (cellulose), (3) it detects and facilitates responses to hormonal and environmental signals involved in the control of cell growth and differentiation
Term
Cyclosis, or cytoplasmic streaming
Definition
The constant movement of the cytoplasm during the life of the cell
Term
The characteristics of diffusion are
Definition
(1) Each molecule moves independently of the others, (2) these movements are random
Term
Plasmolysis
Definition
The separation of the protoplast from the cell wall because of the removal of water from the protoplast by osmosis
Term
Three types of endocytosis
Definition
phagocytosis, pinocytosis, receptor-mediated
Term
Chromatin
Definition
The combination of DNA and its associated proteins in eukaryotic chromosomes
Term
Three ways in which RNA differs from DNA
Definition
(1) The sugar is ribose rather than deoxyribose, (2) thymine found in DNA is replaced by uracil in RNA, and (3) RNA is usually single-stranded and does not form a regular helical structure
Term
Palindromic
Definition
One strand is identical to the other strand when read in the opposite direction
Term
Hardy-Weinberg law
Definition
The proportions, or frequencies, of the alleles and genotypes in a population's gene pool remain constant, or at equilibrium, from generation to generation unless acted upon by agents other than sexual recombination
Term
Hardy-Weinberg equation
Definition
p^2 + 2pq + q^2 = 1
Term
Mutations
Definition
Occur spotaneously, occur at random or by chance
Term
Gene flow
Definition
The movement of alleles into or out of a population
Term
Genetic Drift
Definition
Refers to changes in the gene pool due to chance
Term
Developmental plasticity
Definition
When the observed differences arise directly because of the environmental conditions
Term
Allopatric speciation
Definition
Speciation is most commonly the result of the geographic separation of a population of organisms
Term
Sympatric speciation
Definition
Speciation that occurs without geographic isolation
Term
Autopolyploidy
Definition
Polyploidy leading to the formation of new species as a result of the doubling of chromosome number within individual organisms of a species
Term
Allopolyploidy
Definition
Results from a cross between two different species, producing an interspecific hybrid
Term
Systematics
Definition
The scientific study of biological diversity and its evolutionary history
Term
In 1753, Linneaus...
Definition
published a two-volume work entitled Species Plantarum
Term
Important innovation to the polynomial system devised by Caspar Bauhin (1560-1624) and Linneaus
Definition
Binomial system
Term
Taxon
Definition
The taxonomic group at any level, the level at which it is ranked is called a category
Term
Paraphyletic
Definition
Pertaining to a taxon that excludes species that share a common ancestor with species included in the taxon
Term
Polyphyletic
Definition
Pertaining to a taxon whose members are derived from two or more ancestors not common to all members of the taxon
Term
Principle of parsimony
Definition
The fundamental principle of cladistics is that a cladogram should be constructed in the simplest, least complicated, and most efficient way
Term
Plasmids
Definition
A prokaryotic cell may contain one or more of these smaller extrachromosomal pieces of circular DNA, which replicate independently of the cell's chromosome
Term
Inclusions
Definition
Occassionally prokaryotes contain these, which are distinct granules consisting of storage material
Term
Fimbriae
Definition
Shorter, and more rigid, and typically more numerous that may serve for attachment for prokaryotes
Term
Pili
Definition
Longer and only one or a few are present usually involved in the process of conjugation between prokaryotes
Term
Endospores
Definition
Bacteria have the capacity to form these, dormant resting cells
Term
Prochlorophytes
Definition
A group of photosynthetic prokaryotes that contain chlorophylls a and b, as well as carotenoids, but do not contain phycobilins
Term
Prochloron
Definition
A genus of prochlorophytes that lives only along tropical seashores, as a symbiont within colonial sea squirts; the cells are spherical in shape and contain an extensive system of thylakoids
Term
Prochlorothrix
Definition
A genus of prochlorophytes that is filamentous and has been found growing in several shallow lakes in the Netherlands
Term
Prochlorococcus
Definition
A genus of prochlorophytes that has been found deep in the euphotic zone
Term
Mycoplasmas
Definition
Bacteria that lack cell walls
Term
The extracellular state of viruses
Definition
consist of a nucleic acid core (the viral genome) surrounded by a protein coat
Term
Three types of plant viruses
Definition
the geminiviruses, the badnaviruses, and the caulimoviruses
Term
Capsid
Definition
A shell-like covering that protects the nucleic acid of a virus, which is composed of one or more proteins, called capsid or coat proteins, which assemble in a precise symmetrical manner
Term
Two major structural classes of viruses
Definition
Helical virion and icosahedron
Term
Subliminal
Definition
When viruses remain confined to the intially infected cell
Term
Systemic infection
Definition
Virus infection that moves throughout the plant body
Term
Viroids
Definition
smallest known agents of infectous disease; they consist of small, circular, single-stranded molecules of RNA and lack capsids
Term
Endophytes
Definition
Symbiotic relationships with fungi in which the fungi live inside the leaves and stems of apparently healthy plants. Many of these fungi produce toxic secondary metabolites that protect their hosts against pathogenic fungi and insect attack
Term
Exozymes
Definition
Enzymes excreted by a fungus onto a food source (the smaller molecules that are released are then absorbed at or near the growing tips of their hyphae)
Term
Two types of specialized hyphae
Definition
Rhizoids (anchor some kinds of fungi to the substrate) and haustoria (important for parasitic fungi)
Term
Dikaryon
Definition
In some species of fungi karyogamy does not follow plasmogamy immediately, and therefore the two haploid nuclei do not fuse for some time, forming a dikaryon
Term
Calyptra
Definition
The enlarged venter of the archegonium; as the bryophyte embryo develops, the venter undergoes cell division, keeping pace with the growth of the young sporophyte
Term
Seeds
Definition
Structures that provide the embryonic sporophyte with nutrients and that also help protect it from the rigors of life on land
Term
Dermal Tissue System
Definition
makes up the outer, protective covering of the plant
Term
Vascular tissue system
Definition
comprises the conductive tissues-xylem and phloem; embedded in the ground tissue system
Term
Ground tissue system
Definition
the vascular tissue system is embedded in this complex
Term
Stele
Definition
Central cylinder of stem and root in the primary plant body consisting of the primary vascular tissues and pith
Term
Microphylls
Definition
contain only a single strand of vascular tissue, associated with stems possessing protosteles and are characteristic of the lycophytes, not associated with gaps
Term
Megaphylls
Definition
associated with stems that have either siphonosteles or eusteles, leaf traces associated with leaf gaps and leaf trace gaps, the leaf has a complex system of branching veins
Term
Homosporous
Definition
only one kind of spore as a result of meiosis; found in almost all pteridophytes, equisetophytes, and some lycophytes
Term
Heterospory
Definition
The production of two types of spores in two different kinds of sporangia; found in some of the lycophytes, in a few ferns, and in all seed plants; common as early as the Devonian period, with the earliest record from about 370 mya
Term
Endosporic development
Definition
when gametophyted develop within the spore wall, as in heterosporous plants
Term
Exosporic development
Definition
gametophytes develop outside the spore wall, as in homosporous plants
Term
Polyembryony
Definition
The megagametophyte of gymnosperms produces several archegonia, as a result more than one egg may be fertilized, and several embryos may begin to develop within a single ovule
Term
The colonization of land was associated with the evolution of structures to...
Definition
obtain water and minimize water loss
Term
Plants underwent further adaptations that made it possible for them to reproduce on land:
Definition
1. Production of drought-resistant spores, 2. Evolution of complex, multicellular structures in which the gametes were held and protected from drying by a layer of sterile cells
Term
Co-pigmentation
Definition
The colorless flavones and flavonols can alter the color of a plant part through the formation of complexes with anthocyanins and metal ions. Responsible for some intensely blue flower colors
Term
Systemic acquired resistance (SAR)
Definition
develops in response to a localized attack by pathogenic bacteria, fungi, or viruses
Term
The nucleus performs 2 important functions:
Definition
1. It controls the ongoing activities of the cell by determining which protein molecules are produced by the cell and when they are produced 2. it stores the genetic information, passing it on to the daughter information stored in the nucleus
Term
Three main types of plastids
Definition
Chloroplasts (contain chlorophyll and carotenoid pigments), chromoplasts (contain carotenoid pigments), and leucoplasts (nonpigmented). Proplastids are the precursors of plastids
Term
Peroxisomes
Definition
Organelles bound by a single membrane, posess neither DNA nore ribosomes, and play important roles in photorespiration and/or the conversion of stored fats to sucrose during seed germination.
Term
Hemicelluloses
Definition
Function in the cell to limit the extensibility of the cell wall by tethering adjacent microfibrils regulating cell enlargement
Term
Entrained
Definition
The process by which a periodic repition of light and dark causes a circadian rythm
Term
Synaptonemal Complex
Definition
pairs of homologous chromosomes approach each other very closely
Term
Polysomes
Definition
An aggregation of ribosomes actively involved in the translation of the same RNA molecule, one after another
Term
Prolamellar body
Definition
Semicrystalline body found in plastids arrested in development by the absence of light
Term
Etioplasts
Definition
Plastid of a plant grown in the dark and containing a prolamellar body
Term
Cortical
Definition
Peripheral cytoplasm in cell
Term
Cortical ER
Definition
ER located just inside the plasma membrane of the cell; regulates calcium ions
Term
Hyperosmotic/hypertonic
Definition
[solutes]out >[solutes]in
Term
Isoosmotic/isotonic
Definition
[solutes]out = [solutes]in (normal in animal cells)
Term
Hypoosmotic/hypotonic
Definition
[solutes]out<[solutes]in (normal for plant cells)
Term
Theory of punctuated equilibrium as described by Eldredge and Gould
Definition
Species undergo most of their morphological modification as they first diverge from their progenitors, and then change little even as they give rise to additional species. Long periods of gradual change are punctuated by periods of rapid change
Term
Polyphyletic
Definition
Pertaining to a taxon whose members are derived from 2 or more ancestors not common to all of the members of the taxon
Term
Paraphyletic
Definition
Pertaining to a taxon that excludes species that share a common ancestor with species included in the taxon
Term
Principal of parsimony
Definition
A fundamental principal of cladistics is that a cladogram should be constructed in the simplest, least complicated, and most efficient way.
Term
Molecular clock
Definition
The molecular clock (based on the molecular clock hypothesis) is a technique in molecular evolution to relate the time that two species diverged to the number of molecular differences measured between the species' DNA sequences or proteins. It is sometimes called a gene clock or evolutionary clock.
Term
Statoliths
Definition
Gravity sensors
Term
Acclimation
Definition
The process by which numerous physical and physiological processes prepare a plant for winter
Term
Cold hardiness
Definition
The ability of a plant to survive the extreme cold and drying effects of winter weather
Term
Vernalization
Definition
The induction of flowering by cold treatment
Term
Nastic movements
Definition
A plant movement in response to an external stimulus, with direction of movement unrelated to the direction of the stimulus
Term
Nyctinastic movements (Nyctinasty)
Definition
Night closure or sleep movements. Up and down movements of leaves in response to the daily changes of light and darkness and horizontally in the light
Term
Pulvinus
Definition
Jointlike thickenings at the base of the petiole of a leaf or petioule of a leaflet, and having a role in the movements of the leaf or leaflet.
Term
Thigmonastic movements (Thigmonasty)
Definition
Movement resulting from mechanical stimulation (i.e. sensitive plant) Leaves and leaflets droop suddenly in response to touch by sudden changes in turgor pressure in pulvinus cells at the base of each one
Term
Both cytokinin and auxin...
Definition
Appear to regulate root gravitropism, cytokinin in an early, rapid phase very near the root apex, and auxin in a later, slower phase farther from the root apex
Term
Short-day plants
Definition
Flower in the early spring or fall; they must have a light period shorter than a critical length 
Term
Long- day plants
Definition
Flower in the summer; require light periods that are longer than a critical length
Term
Progymnosperms
Definition
Reproduced by means of freely dispersed spores, they produced secondary xylem remarkably similar to that of living conifers, also produced secondary phloem, elaborate and highly differentiated branch system and more complex vascular system
Term
Ovuliferous
Definition
Cone scales; bearing the ovules 
Term
Matrotrophy
Definition
Food derived from the mother
Term
Bifacial vascular cambium
Definition
The most important evolutionary advance by the progymnosperms over both the trimerophytes and the ferns, producing both secondary xylem and phloem.
Term
Parenchyma tissue
Definition
Living when functional; throughout the plant body, as parenchyma tissue in cortex; as pith and pith rays; in xylem and phloem. Involved in metabolic processes (i.e. respiration and photosynthesis), storage and conduction, and wound healing and regeneration. In leaf mesophyll and in felsh of fruits
Term
Collenchyma tissue
Definition
Living when functional; in young elongating stems; support in primary plant body
Term
Sclerenchyma tissue
Definition
(fiber cells) Often functional cells dead; sometime in cortex of stems, most often with xylem and phloem, and in leaves of monocots; support and storage. Two types: fibers and sclereids
Term
Sclereid cells
Definition
living or dead when functional; found throughout the plant; mechanical and protective functions
Term
Three hypotheses for how shoots and roots perceive gravity
Definition
Starch-statolith hypothesis, protoplast pressure hypothesis, and tensegrity hypothesis
Term
endogenous
Definition
controlled internally, i.e. internal timing, biological clock, circadian rhythm
Term
mesocotyl
Definition
In grasses, the part of the embryo axis between the scutellum and the coleptile
Term
Role of bud scales
Definition
Similar to seed coat; prevent dessication, restrict movement of oxygen into the bud, and insulate the bud from heat loss
Term
abscission
Definition
shedding, of leaves, flowers, and fruits
Term
Casparian strip
Definition
band-like region of the primary wall of the endodermis containing suberin and lignin, which functions to prevent water loss
Term
Sorus
Definition
the structure where the sporangia are held
Term
Indusium
Definition
the protective cover on the undersurface of the leaf that protects the sorus and sporangia
Term
Casparian strip
Definition

The inner most layer of cortex—endodermis—is compactly arranged and lacks air spaces—these strips are found here. It is a wall thickening and an integral band-like portion of the primary wall and middle lamella that is impregnated with suberin and lignin. They are therefore impermeable to H2O—prevent water loss.

 

Term
Quiescent center
Definition

region of the apical meristem® corresponds to the promeristem (the initials and their derivatives)

 

It is able to repopulate the bordering meristematic regions when injured. Studies suggest that this center plays an essential role in organization and development of the root.

 

Most cell division occurs a short distance from this center.

 

Term
pneumatophores
Definition

Negatively gravitropic extensions of the root systems of some trees growing in swampy habitats; they grow upward and out of the water and probably function to ensure adequate aeration.

 

Term
prop roots
Definition

Adventitious roots arising from the stem above soil level and helping to support the plant; common in many monocots, for example, maize

 

Term
Sucrose
Definition

This is the primary form in which sugar produced by photosynthesis is translocated

 

Term
Carotenoids
Definition

Act as accessory pigments in photosynthesis; principle function is anti-oxidant, preventing oxidative damage to the chlorophyll molecules by light

 

Term
Rubisco
Definition

The enzyme that catalyzes initial reaction of the Calvin cycle, involving the fixation of carbon dioxide to ribulose 1,5-bisphosphate (RuBP)

 

Term
Jasmonates
Definition

A class of compounds known as oxylipins important in plant growth regulation and defense.

 

Term
Chytridiomycota
Definition
Aquatic; Hyphae are aseptate, coenocytic; asexual reproduction via zoospores. Distinguished from other fungi primarily by their characteristic motile cell, most of which have a single, posterior, whiplash flagellum.
Term
Zygomycota
Definition
Hyphae are aseptate, coencytic; asexual reproduction via nonmotile spores born in sporangia; sexual zygospores through the fertilization of+ ans - strains growing together
Term
Ascomycota
Definition
Hyphae are septate; asexual reproduction via budding, conidia (nonmotile spores), fragmentation; sexual reproduction via ascospores. Formation of ascus and ascospores formed following meiosis.
Term
ground tissue system consists of...
Definition
parenchyma, collenchyma, and sclerenchyma
Term
Basidiomycota
Definition
Hyphae are septate, with dolipore in many species; asexual reproduction via budding, conidia (nonmotile spores), fragmentation; sexual reproduction via basidiospores
Term
Homothallic
Definition
species in which the individuals are self-fertile
Term
Heterothallic
Definition
species in which the haploid individuals are self-sterile or not compatible

Term
Ectomycorhizae
Definition

 

surround the root cells; found primarily in temperate regions. In conifers, the hyphae grow between the cells of the root epidermis and cortex, forming a highly branched network called the Hartig net. Ecto are also characterized by a mantle, or sheath, of hyphae that covers the root surface, and are mostly formed with Basidiomycetes. At least 5000 spp. Are involved in ecto associations, often with a high degree of specificity

 

Term
Endomycorhizae
Definition
penetrate the root cells; more common, occurring in ~80% of all vascular plants; the fungal component is a zygomycete and these relationships are not highly specific; the fungal hyphae penetrate the cortical cells of the plant root and this is where they form highly branched structures called arbuscules (and in some cases terminal swellings called vesicles). The arbuscules do not enter the protoplast but greatly invaginate the plasma membrane of the cortical cell, increasing its surface area and facilitating the transfer of metabolites and nutrients (most exchange takes place at the arbuscules).

Term
allele
Definition

One of the two or more alternative forms of a gene.

 

Term
homology
Definition

A condition indicative of the same phylogenetic, or evolutionary origin, but not necessarily same in present structure and/or function.

 

Term
CAM
Definition

Crassulacean Acid Metabolism- A variant of the C4 pathway; phosphoenolpyruvate fixes CO2 in C4 compounds at night and then, during the daytime, the fixed CO2 is transferred to the ribulose bisphosphate of the Calvin cycle within the same cell.

 

Term
ontogeny
Definition

The development, or life history, of all or part of an individual organism.

 

Term
genome
Definition

The totality of genetic information contained in the nucleus, plastid, or mitochondian.

 

Term
Lenticel
Definition

Spongy areas in the cork surfaces of the stem, roots, and other plant parts that allow interchange of gases between internal tissues and the atmosphere through the periderm; occur in vascular plants. 

 

Term
apomixis
Definition
reproduction without fertilization or meiosis
Term
Conidia
Definition

An asexual fungal spore not contained within a sporangium; it may be produced singly or in chains; most conidia are multinucleate.

 

Term
polar nuclei
Definition

Two nuclei (usually), one derived from each end (pole) of the embryo sac, which become centrally located;  they fuse with a male nucleus to form the primary (typically 3n) endosperm nucleus.

 

Term
sporophyll
Definition

A modified leaf or leaf-like organ that bears sporangia; applied to the stamens and carpels of angiosperms, fertile fronds of ferns, and other similar structures.

 

Term
antheridium
Definition

A sperm-producing structure that may be multicellular or unicellular.

 

Term
thallus
Definition

A type of body that is undifferentiated into root, stem, or leaf; the word thallus was used commonly when fungi and algae were considered to be plants, to distinguish their simple construction, and that of certain gametophytes, from the differentiated bodies of plant sporophytes and the elaborate gametophytes of the bryophytes.

 

Term
Archaea
Definition

A phylogenetic domain of prokaryotes consisting of the methanogens, most extreme halophiles and hyperthermophiles.

 

Term
plastid
Definition

Organelle in the cells of certain groups of eukaryotes that is the site of such activities as food manufacture and storage; plastids are bound by two membranes.

 

Term
To keep a population in H-W equilibrium:
Definition

Random mating, large population, isolation, no mutations, and no natural selection

 

Term
Exon
Definition
A segment of DNA that is both transcribed into RNA and translated into protein; exons are characteristic of eukaryotes
Term
Phycobilins
Definition
A group of water-soluble accessory pigments, including phycocyanins and phycoerythrins, which occur in the red algae and cynobacteria
Term
Vacuole
Definition
A space or cavity within the cytoplasm filled with a watery fluid, the cell sap; a lysosomal compartment
Term
Heartwood
Definition
Non-living and commonly dark-colored wood in which no water transport occurs; it is surrounded by sapwood
Term
Parenchyma tissue
Definition
involved in photosynthesis, storage, and secretion
Term
Collenchyma Tissue
Definition
Supports young growing organs
Term
Sclerenchyma tissue
Definition
strengthen and support plant parts no longer elongating
Term
Micropyle
Definition
In the ovule of seed plants, it is the opening in the integuments through which the pollen tube enters
Term
Thorns
Definition
modified branches
Term
spines
Definition
modified leaves
Term
prickles
Definition
extensions of the cortex or epidermis
Supporting users have an ad free experience!