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Covenant Bio112 Exam 1
N/A
230
Biology
Undergraduate 1
03/23/2012

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Term
Types of Revelation
Definition
General Revelation
Special Revelation
Term
What we should avoid:
Definition
1. Ad hominem attacks with those of differing opinions
2. Abandoning attempts to reconcile special and general revelation
3. Jumping to shallow conclusions
Term
What we should pursue tenaciously:
Definition
1. Humility
2. Humbly realize the fallness of our faculities
3. We do not understand all of creation
Term
Six Day Interpretation of Creation Days
Definition
Young earth--500 years old
Most straightforward reading
Term
Day Age Interpretation of Creation Days
Definition
"Yom" as used as age instead of a literal 24 hour day
Refer to different scientific evidence
Genesis is historical account but the days are not 24 hours long.
Term
Analogical Day Interpretation of Creation Days
Definition
Days are God's work days, not identical to our days.
Days are not a known length--logical rather than chronological.
Term
Framework Theory about Creation Days
Definition
Creation week is a metaphor, days are poetic vehicles.
Length of days are unspecified, timing is unimportant.
Term
Sedimentary Rock Strata
Definition
-Simpler organisms in deeper strata
-Complex organisms in higher strata
-Show distinctive assemblies of fossil organisms
Term
Radiometric dating of fossils (indirect measures)
Definition
-Carbon 14
-decays into Nitrogen 14 over a long period of time
-Radioactie isotype of carbon
-Ratio of C12 to C14 can suggest age of specimen
-Assumes that production of C14 in the atmosphere is constant.
-Potassium 40
-Deposited in volcanic rock layers
-As it decays, it is changed to Argon 40.
-Limits of radiometric dating:
-Require assumption about initial amounts present in a material.
Term
Proposed Geologic Eons, Eras, and Periods
Definition
-Hadean Eon
-Archaean Eon
-Proterozoic Era
-Phanerozoic Era
Term
Hadean Eon
Definition
-4.5 billion years ago
-toward the end of this eon, prokaryotic (bacteria) appears
Term
Archaean Eon
Definition
-3.8 billion years ago
-Photosynthetic bacteria
-1st eukaryotic cells
Term
Proterozoic Era
Definition
-2.5 billion years ago
-Multi-cellular eukaryotic
-Bilateral Eukaryotes-have back and bellyy
Term
Phanerozoic Era
Definition
-543 million years ago
-Cambrian Explosion-reptiles, amphibians, etc. suddenly show up
Term
Biological Evolution
Definition
-A heritable change in one or more characteristics of a population (of a single species) or species across many generations
-From a genetic perspective, involves changes in allele over time.
-Viewed in a smaller scale, relating to genetic or phenotypic changes within a population over time=Microevolution
-Viewed on a larger scale relating to formation of new species or groups of species=Macroevolution
Term
Species
Definition
-Groups of related organisms that share a distinctive form, function.
-Among species that reproduce sexually, members of the same species are capable of interbreeding to produce viable and fertile offspring.
Term
Charles Darwin
Definition
-British naturalist born in 1809
-1858-presented evolution at a meeting of Linnaean society
-1859-ideas published in "Origins of Species"
-Alfred Russell Wallace independently came up with a similar theory
Term
Natural Theology
Definition
-Creator's plan could be understood by studying nature
-Characteristics/adaptations in organisms were evidence that creatures were designed for a particular purpose.
Classification allowed an appreciation of the hierarchical steps on the ladder of life.
Term
Influences on Darwin's Thinking
Definition
1. Linneaus (1707-1778)
-Father of taxonomy
-Came up with the idea that classifications were not attempts to establish evolutionary relationships
2. Cuvier (1769-1832) and Catastrophism
-Interpreted fossil strata as record of life's history
-Speculated that boundaries between fossil strata correspond to the time of historical catastrophic events.
-Catastrophic events caused mass extinctions.
-Changes show immigration of species.
3. James Hutton (1726-1797) and Charles Lyell (1797-1895)
-Profound geological change due to slow, continuous process that continue to operate in the world
-Against all of Catastrophism
-Ex. Canyons form by erosion-suggests old earth
4. Lamarck (1744-1829)- a drive toward complexity
-Early evolution model-1809
-Organisms have tendency to adapt and change in response to environment.
-A continuous line of descent from simple to complex organisms
-Adaptation-Organs and structures not used deteriorate, those that are used in survival tend to be strengthened. Theses are heritable in offspring.
-Ex. giraffe
5. Other influences on Darwin's Thinking
-Thomas Malthus, an Anglican minister and "doomsday" economist
-unchecked population growth would inevitably lead to famine, disease, and ceaseless struggle for existence.
-Don't have so many kids
-Selective Breeding
-Many traits are transmitted from parents to offspring.
-Designed to modify traits in domesticated species
-Might natural forces alter the features of living organisms over time?
Term
Darwin's voyage on The Beagle
Definition
-1831-1836
-South America was major focus.
-Darwin was asked to examine living resources.
Term
Darwin's Observations
Definition
-South America's flora and fauna were distinct from that found in Europe.
-Read Well's Principles of Geology-became convinced of uniformitarian view of ancient and changing earth.
-Temperate South America flor and fauna were more similar to tropical South America flora and fauna than organisms in similar temperate climate in Europe.
-South America flora and fauna resembled the fossils in temperate South America.
-Distinct traits of island species that provided them ways to better exploit their native environment.
-Galapagos island chain-species were similar to mainland species
Term
Darwin's Conclusions
Definition
-Descent with Modification
-Two separated populations of a species could diverge as each adapted to local conditions
-If environment conditions change drastically, a species characteristic could change over time.
-Over many generations, because of divergence, new species will arise.
-Conclusion: All species are related through ancestral connections
Term
Darwin's Conceptual Framework
Definition
Observation 1
-If all individuals survive to reproduce to the extent to which they are capable of, populations would tend to grow exponentially.
Observation 2
-Environmental resources are limited.
-Inference 1
-Reproductive activity can lead to a struggle for existence, not all will survive.
-Populations tend to remain stable in size over time.
Observation 3
-Variations in many observable traits abound in populations of organisms
Observation 4
-Much of this variation is heritable.
-Inference 2
-Survival is not random but may depend on how well adapted an individual is to compete for resources.
-Natural Selection: Best fit individuals will leave more offspring.
-Inference 3
-Populations will shift to more adaptiveness-will be able to survive prevailing conditions
Term
The "Modern Synthesis"
Definition
-Darwin's theory preceded Mendel's genetic works; no conception of mechanism of inheritance.
-Genetics has allowed us to understand the relationship between traits and heritability.
-Key Features:
-Natural variation exists that is caused by random changes in the genetic material.
-Genetic changes may be advantageous, disadvantageous, or neutral.
-If genetic change promotes an individual's survival and/or ability to reproduce, natural selection may increase the prevalence of that trait in future generations.
Term
Evidence Cited in Support of Evolution
Definition
-The Fossil Record
-Much of what we know about the history of life on Earth comes from the study of fossils.
-Broad patterns
-Simpler forms in lower strata, complex forms in upper strata.
-Fossils show that many changes suddenly appear; gradual changes are relatively rare. Punctuated equilibrium.
-Darwin-some universal ancestor, tree with diagonal lines, throughout time there would be slow, incremental morphological change in the body form throughout the ancestors
-In actual fossil record-common ancestor, through time it doesn't change too much, suddenly many new forms are developed in the fossil record
-Cambrian Explosion-a lot of diverse animal forms appear without any precursors in the fossil record
-Rapid rates of evolution have been suggested to occur when changes in the physical and biological environment create conditions that favor new traits.
-Emergence of novel features
-Truly novel features of organisms appear infrequently. Most changes in fossil organisms involve alterations of structures that already exist in organisms from lower strata.
Term
Examples of Evidence Found in Support of Evolution
Definition
1. Fishapod (Tiltaalik rosease)
-Suggested to be a transitional form between fish and tetrapods; provides link between earlier and later forms
-Had broad skull, flexible neck, eyes on top, primitive wrist, and five fingers
2. Oysters
-Fossil evidence suggests that 200 mya, some oysters underwent shell changes.
-Smaller, curved shells were superseded by larger, flatter shells.
-Hypothesis: Flatter shells are more stable in disruptive water currents and so were better adapted if water currents became stronger.
Term
Biogeiography
Definition
-The study of geographical distribution of extinct and modern species
-Extinct species fossil distributions
-Continental Drift-fossils of very similar organisms are on both continents
-Modern species distributions
-Isolated continents and island groups have evolved their own distinct plant and animal communities.
-Immigration of initial populations, then divergence
-Island species resemble those found on closest mainland, with adaptational changes.
-Geological change may foster separation of populations, set up distinct selection conditions.
Term
Convergent Evolution
Definition
-Two different species from different proposed ancestral lineages show similar characteristics and occupy similar environments.
-Examples of proposed convergent traits
-Giant anteater and echidna both have long snouts and tongues to feed on ants
-Aerial rootlets for clinging in English ivy and wintercreeper.
-Overall body form of dolphins and fish
-Antifreeze proteins in different very coldwater fish
Term
Homology
Definition
A similarity in structure in two distinct species that is attributed to a common ancestor that had that structure
-Many different categories of homology have been sued to establish relationships between species.
-Circular Reasoning
Term
Anatomical Homology
Definition
-Homologous physical structures are structures in different species proposed to be derived from common ancestor.
Example: Same set of bones in the limbs of modern vertebrates proposed to have undergone evolutionary change to be used for many different purposes.
-Vestigial structures are anatomical structures that have highly reduced and has no apparent current function (but resemble functional structures of presumed ancestors)- it is not needed in a species' environment
-Ear wiggling muscles, tail bone, appendix in humans (recently proven to be beneficial in the immune system)
-Pelvic bones in some snakes and whales
Term
Development Homology
Definition
-Subcategory of Anatomical Homology
-Species that different as adults often bear significant similarities during embryonic stages
-Notochord present in diverse chordate species
-Presence of branchial arches (gill ridges) in human embryos and fish embryos
-Teeth in embryonic baleen (long fibrous filtering system in mouth) whales
-Human embryos have long bony tails
Term
Molecular Homology
Definition
-Similarities in biochemical characteristics of cells suggest (to some) that all like arose from a single common ancestor
-All living species use DNA to stor information.
-Processing of information to yield proteins in similar.
-Certain biochemical pathways are found in all or nearly all species.
-Examples: Glycolysis pathway, Kreb's cycle
Term
Genetic Homology
Definition
-Homologous genes- two genes derived from the same ancestral gene
-May reveal possible molecular details of evolutionary change
-Two sequences may be similar due to the same ancestral gene but not identical due to the independent accumulation of different mutations over time.
-The longer the time since the hypothetical common ancestor, the greater the divergence.
-Morphological Tree vs. Molecular Tree
-They don't always match up. Scientists are now trying to combine the two different types of trees.
Term
The Concept of Species
Definition
-Known number of species: 1.4 million
-Estimates of unidentified species: 2 million to 100 million
Term
Difficult in identifying a "species"
Definition
-A single species may exist in 2 distinct populations that may be thought to be in the slow process of evolving into 2 or more distinct species.
-When do you draw the line to say that they are two distinct species?
Term
Ways of Defining Species
Definition
1. Morphological (physical attributes) Species Concept
-Species are identified by having a unique combination of physical traits.
-Historically, emphasized physical traits, but now extended to include DNA/protein sequence traits.
-Advantages
-Can be applied to all organisms, both asexual and sexual organisms.
-Can be applies to extinct organisms.
-Drawbacks
-How many/which traits should be considered?
-Traits often vary in a continuous way, so where to draw the line?
-Members of the same species can look very different while members of a different species (defined in other ways) can look very similar.
2. Biological Species Concept
-A species is a group of individuals whose members have the potential interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species.
-Defined by reproductive isolation in natural environments (hybrids may be possible in artificial environments such as labs or zoos.)
-Problems:
-May be difficult to determine in 2 populations are truly reproductively isolated.
-Cannot be applies to asexual species or extinct species
Term
Evolutionary/Phylogenetic/Chadistic Species Concept
Definition
-A species is derived from a single lineage that is distinct from other lineages and has its own evolutionary tendencies and historical fate
-Lineage
-Genetic relationship between an individual or group of individuals and its ancestors
-Species are unbranched lines of phylogenetic trees.
-Drawback-lineages difficult to examine and identify; oftentimes controversial
Term
Ecological Species Concept
Definition
-Each species occupies a unique ecological niche.
-Unique set of habitat resources that a species requires, as well as its influence on the environment and other species.
-Within their own ecological niche, members of a given species compete with each other for survival.
-If two organisms are very similar, their specific needs will overlay, which results in competition.
-Individuals competing for identical resources are likely to be of the same species.
-Useful for identification of asexually reproducing species, such as bacteria and protist species.
-Drawbacks
-Depends on how fully the niche, needs of the organisms are known.
-Convergent evolution?
Term
Reproductive isolation mechanisms
Definition
-Driving force for biological speciation
-Consequence of genetic change as diverging species/populations adapt their environments, preventing exchange of genetic material
-Prezygotic barriers
Term
Prezygotic barriers
Definition
-Prevent two species from reproducing sexually
-Prevent formation of zygote (first cell after fertilization)
Term
Habitat isolation
Definition
-Prezygotic barrier
-Geographic barrier prevents contact
Term
Temporal Isolation
Definition
-Prezygotic barrier
-Reproduce after different times of the day or year
-Spring field cricket and fall field cricket
Term
Temporal Isolation
Definition
-Prezygotic barrier
-Reproduce after different times of the day or year
-Spring field cricket and fall field cricket
Term
Temporal Isolation
Definition
-Prezygotic barrier
-Reproduce after different times of the day or year
-Spring field cricket and fall field cricket
Term
Behavioral Isolation
Definition
-Behaviors important in mate choice
-Changes in song
Term
Mechanical Isolation
Definition
-Size and incompatible genitalia prevents mating
Term
Gametic Isolation
Definition
-Gametes fail to unite successfully
-Block development of viable, fertile individuals
-Allow fusion of sperm and egg from different species
-Important in species that release gametes into the water or air
Term
Allopatric Speciation
Definition
-Proposed to be the most common source of evolution, cladogenesis (splitting of lineages)
-Occurs when some members of a species become geographically separates, and then diverge
-Can also occur when small population moves to a new location that is geographically separated: "founder effect" (this population may not be genetically typically)
-Genetic drift and natural selection may quickly lead to differences
-Adaptive radiation-single species evolves into array of descendants that differ greatly in habitat, form, or behavior
Term
Sympatric Speciation
Definition
-Proposed to occur when members of a species that initially occupy the same habitat within the same range diverge into two or more different species
-Interbreeding issue
-Involves abrupt genetic changes that quickly lead to the reproductive isolation of a group of individuals (otherwise, hybridization would erase the divergence)
-Example: Changes in chromosome number in plants
-Autopolyploidy
-Allopolyploidy
-Xenopus laevis (frog)-proposed to be an allotetraploid species
-Issue: this type of speciation relies on a lot of unusual events
Term
Autopolyploidy
Definition
-Plants have more than the normal sets of chromosomes
-Non-disjunction of chromosomes during meiosis, self-fertilization
-Tetraploid species formed (crossing with diploid would not produce fertile offspring)
-Observed by DeVries in primroses in early 20th century (28 chromosomes, rather than 14)
Term
Allopolyploidy
Definition
-Results from cross fertilization between two species
-A hybrid is produced that is most often sterile, but can reproduce asexually.
May restore sexual reproduction through subsequent chromosome duplication (to produce two chromosomes of each type)
Term
Plat Diversity Overview
Definition
-Division=Phylum
-By far, flowering plants make up the most diverse plant division.
More flowering plant species than all other combined.
-All plants exhibit "alteration of generations"
-A sequence in a life cycle in which a haploid (half the number of chromosomes), gamete-producing phase is followed by a diploid, (spore-producing phase has two chromosomes); the spores of the latter reinitiate the haploid phase
-Gametophyte (haploid)
-Microscopic in flowering plants
-Produces gametes by mitosis
-Sporophyte (diploid)
-In flowering plants, large independent, recognizable plant
-Produces spores by meiosis (haploid spores)
Term
Flowering Plant Reproductive Development
Definition
-Mature flowering plants produce seeds and fruits
-Flower tissue enclose and protect tiny male and female gametophytes
-Fruits enclose seeds and function in seed dispersal
-Can also protect seeds from environment
-Seeds enclose plant embryos
Term
Annuals
Definition
-Plants that die after producing seeds during their first year of life
Term
Biennials
Definition
-Plants that do not reproduce the first year but may the following year
Term
Perennials
Definition
-plants that live for more than 2 years, often producing seed every year after maturity
Term
Four Essential Processes of Plant Growth and Development
Definition
1. Cell division (mitosis)
2. Growth
3. Cell specialization
4. Apoptosis (programmed cell death)
Cell migration does not occur during development of plants (unlike animals)-cells mature, differentiate where they are laid down
Term
Principles of Plant Growth and Development
Definition
-Development and maintenance of a distinctive architecture throughout life
-Maintenance of populations of stem cells in meristems
-Stem cells-unspecified cells, capable of producing cells that can differentiate into a number of different cell types
-Meristematic stem cells divide to renew meristems, and leave cells behind to differentiate.
-Growth by expansion of cells in controlled directions, by water uptake
Term
Shoot Apical Meristems
Definition
-Shoot apical meristems (SAM)
-Rapidly dividing cells at shoot tips and branches
-Produces shoot systems
-Stems, branches, leaves, and other organ systems
Term
Root Apical Meristems (RAM)
Definition
-Rapidly dividing cells at root tips
-Produce root system
-Roots and root branches
Term
Primary Meristems
Definition
-SAM and RAM produce additional meristematic tissues (primary meristems) that produce specialized primary tissues
Term
Three Types of Primary Meristems
Definition
1. Protoderm-generates epidermis
2. Procambium-produces vascular tissues (primary xylem and phloem)
3. Ground meristems-produces ground tissues (cortex and pith)
Term
Secondary Meristems
Definition
-Lateral meristems
-Surround the established stem of a plant and cause it to grow laterally (i.e larger in girth/diameter)
-vascular cambium
-Cells are pushed into the stem, making it grow out.
-Cork cambium
-Secondary meristems produce secondary tissues.
Term
Stem Cells
Definition
-Plant meristems contain stem cells that remain undifferentiated but can produce new cells capable of differentiating into specialized tissues.
-Plant stem cell divide to produce one cell that remains unspecialized and another cell that is capable of differentiating into various types of specialized cells
Term
Plant Cell Expansion
Definition
-Enclosed in a cell wall, but plants can undergo processes to loosen up or stretch the cell wall. This process becomes possible through the intake of water through the vacuole. THis water causes pressure in the cell wal, causing the cell wall to stretch and grow.
-Growth in plant involves:
-Producing new cells
-Cell expansion
-Expansion occurs when water enters the central vacuole by osmosis
-Allows for rapid cellular growth rate
Term
Leaves
Definition
-Main photosynthetic (ATP/glucoses is being synthesized) systems
-Site of gas exchange
-Susceptible to water loss, drying
-Water loss can be useful to the plants because through evaporation, water is pulled up from the roots to the tips of the plants
Term
Simple leaves
Definition
-Only one blade
-Advantageous in shade by providing maximal light absorption
Term
Complex or compound leaves
Definition
-Dissected into leaflets
-Common in hot environments for heat dissipation
Term
Leaf Venation
Definition
-Eudicot leaves have pinnate or palmate venation
-Monocot leaves have parallel venation
Term
Leaf Surface Features
Definition
-Waxy cuticle on epidermis helps avoid desiccation (water loss).
-Filter UV radiation, reduce microbe and animal attack (similar to sunscreen).
-Guard cells regulate stomatal opening and closing.
-Stomata are encircled by guard cells.
-Guard cells are prone to close when they are stressed out because it is very hot outside and at night to prevent water loss.
-Trichomes offer protection from excess light, ultraviolet radiation, extreme air temperature, or attack by herbivores.
Term
Modified Leaves
Definition
-Most leaves function primarily in photosynthesis
-But leaflike primordial tissues can modify their development for other roles
-Tendrils
-Tough scales that protect buds
-Poinsettia "petals"-the red petals are actually just leaves with pigmentation change
-Cactus spines
Term
Stems
Definition
-Support for the plant body
-Few millimeters to 100 meters in length
-Carries nutrients throughout plant (in vascular tissues)
-Defense system to protect against predators and infection
-Produces leaves, branches, and flowers
-Hold the leaves up
-May function in storage and photosynthesis
-Nodes-attachment for leaves and branches
-Internodes-regions between the nodes
-Buds-contain meristematic tissue, areas of growth (stems, leaves, and flowers)
Term
Stem Vascular Tissue
Definition
-Primary vascular tissue will be derived from primary meristem (procambium)
-Secondary vascular tissue will be derived from secondary meristem (vascular cambium)
Term
Herbaceous vs. Woody Vascular Tissue
Definition
-Herbaceous (non-woody) plants produce mostly primary vascular tissues.
-Woody plants produce primary and secondary vascular tissue.
-Woody plants begin as herbaceous seedling with only primary vascular systems.
Term
Three Domain Phylogeny
Definition
-Two prokaryotic domains-Archaea and Bacteria (these two groups used to be one group known as Eukaryota)
-Eukaryota is also a domain.
-Archaea are exrymophiles, outwardly resemble bacteria.
Term
Structure of Bacteria
Definition
-Cell shape (one aspect of bacterial taxonomy)
-Spherical-cocci
-Rod-shaped-Bacilli
-Spiral-shaped-Spirochaetes
-Slimy Mucilage-secreted coat that serve variety of functions
-Protection from immune reactions of host species
-Avoidance of drying out
-Holds cell together, keeps them from washing away
-Cell Wall Structure
-Helps to maintain cell shape and help protect against attack
-Also helps avoid lysis in hypotonic solutions
-Archaea and some bacteria use protein
-Most bacteria use peptidoglycan
-Gram-positive-thick peptidoglycan layer outside plasma membrane
-Gram-negative-thin peptidoglycan layer outside of plasma membrane
-Additional lipid bilayer outer envelope, outer leaflet not in lipoplysaccharides.
Term
Peptidoglycan
Definition
-Polymer of sugar and amino acid subunits
Term
Motility of Bacteria
Definition
-Flagella-spinning filament, allows swimming behavior
-can be single or multiple
-Pili-threadlike structures extend or retract, allow gliding movement across a surface
Term
Reproduction of Bacteria
Definition
-Binary Fission-chromosome replicate, copies moved toward opposite poles; plasma membrane pinches inward, new cell wall material deposited
-Akinetes and Endospores
-Akinetes-food filled
-Cyanobacterial cells can survive winter conditions in frozen lakes
-Endospores-bacterial cells form tough protein coats that protect against water loss. Can live for centurues. Bacillus anthracis, Clostridium botulinum (food poisoning), Clostridium tetani
Term
Ecological Roles of Bacteria and Archaea
Definition
-Autotrophs vs. Heterotrophs
-Aerobic vs. Anaerobic
Term
Autotrophs vs. Heterotrophs
Definition
-Autotrophs-"producers", produce their own ATP, and all or most of needed organic molecules
-Photoautotrophs (Cyanobacteria)
-Chemoautotrophs
-Heterotrophs-require organic molecules from external source (humans)
Term
Aerobic vs. Anaerobic
Definition
-Aerobic-utilize oxygen in respiration (humans)
-Obligate-must have oxygen
-Facultative-can switch to anaerobic mode in the absence of oxygen
-Anaerobic-no oxygen, anaerobic respiration (can be obligate anaerobes or aerotolerant)
Term
Prokaryotic Organisms and the Carbon Cycle
Definition
-Producers-autotrophs, build complex carbon compounds, fix carbon
-Decomposers-break down carbon compounds, release carbon dioxide
Term
Prokaryotic Organisms and the Nitrogen Cycle
Definition
-Diazotrophs take atmospheric nitrogen (N2), and convert it to ammonia (which can be used to synthesize amino acids and nucleotides)
-Can form close associations with plants-Rhizobium nodules and legumes
Term
Traditional Subdivisions of the Domain Eukarya
Definition
1. Protista
2. Fungi
3. Plantae
4. Animalia
Term
Kingdom Protista
Definition
-All sorts of organisms
-Simplest eukaryotes
-Most unicellular but some are colonial, multicellular
-Some photosynthesis, while others eat bacteria or other protists
-Most live in wet or aquatic habitats
-This kingdom has been a catch-all. Eukaryotes that are not classified in the plant, animal, or fungi kingdoms (though some protists appear closely related to plants or animals or fungi.
-Not considered a monophyletic group
-Supergroups have been assigned (groupings about kingdom/phylum level)
Term
Kingdom Protists Classified by Habitat
Definition
-Particularly common and diverse in oceans, lakes, wetlands, and rivers.
-Plankton-free swimming or floating
-Phytoplankton-photosynthesis
-Protozoan plankton-heterotrophic
-Occur primarily as single cells, colonies, short filaments
Term
Kingdom Protista Classified by Mode of Motility
Definition
-Swim using eukaryotic flagella
-Cila-shorter and more abundant than flagella
-Amoeboid movement-using pseudopodia
Term
Kingdom Protista Classified by Four Basic Types of Nutrition
Definition
-Phagotrophs-heterotrophs that ingest particles
-Osmotrophs-heterotrophs that rely on uptake of small organic molecules
-Autotrophs-photosynthetic
-Mixotroph-able to use autotrophy and phagotrophy or osmotrophy depending on conditions
Term
Asexual Reproduction in Kingdom Protista
Definition
-All protists can reproduce asexually by mitosis (some reproduce sexually)
-Many can produce cysts with thick, protective walls that remain dormant in bad conditions
-many protozoan pathogens can spread from one host to another via cysts
Term
Xylem
Definition
-Primarily responsible for the transport of water and dissolved minerals from roots upward in plant body through process of evaporation
-In vascular bundle, located towards the center of stem
Term
Phloem
Definition
-Primarily responsible for the transport of organic nutrients (dissolved sugars) from leaves or roots to other areas of the plant (flow can occur in both directions, depending on the time of year)
Term
Arrangement of vasculature
Definition
-Monocots-scattered arrangement of vascular bundles
-Generally herbaceous, no vascular cambium
-Dicots-fewer vascular bundles organized in a ring
-Pith-parenchyma cells inside the ring
Term
Primary Xylem
Definition
-Composed of: tracheids and vessel elements (dead cells)
-Conduct water and dissolved minerals
Term
Primary Phloem
Definition
-Composed of:
-Sieve elements (living cells)
-Companion cells (also living) and sieve element function
-Parenchyma cells
-Supportive fibers
Term
Secondary Vascular Tissue
Definition
-Secondary vascular tissues produced by vascular cambium.
-Secondary xylem-wood
-Secondary phloem-inner bark
-Secondary xylem conducts most of a woody plant's water and minerals may function several years.
-Usually only the current year's production of secondary phloem is active in food transport.
-Bark composed of outer bark (mostly dead cork cells from cork cambium) and inner bark (secondary phloem from vascular cambium)
-Cork cambium produces outer bark, which protects the surface of the tree as it grows in diameter. Cork cells dead when mature and layered with lignin and suberin (help to prevent water loss)
Term
Postzygotic Barriers
Definition
-Hybrid inviability
-Fertilized egge cannot progress pasty early embryonic stages
-Hybrid sterility
-Interspecies hybrid viable but sterile (not fertile)
-Ex. horse and donkeys can interbreed, but they produce offspring that is sterile.
-Hybrid breakdown
-Hybrids viable and fertile but subsequent generations have genetic abnormalities
Term
Modified Stems
Definition
-Rhizomes-underground stems
-Stolons-aboveground creeping stem
-Tubers-(potatoes) and bulbs (onions, irises, and tulips) are underground modified stems that store food
-All of the above allow for asexual (vegetative) reproduction
Term
Root Structure
Definition
-Epidermis of mature roots encloses region of group parenchyma-root cortex
-Root cortex cells often rich in starch (food storage site)
-Primary vascular system includes xylem enclosed in phloem
-Pericycle encloses root vascular tissue
-Produces lateral (branch) roots
-Woody roots produce primarily vascular tissues followed by secondary vascular tissues
Term
Root Growth
Definition
-Root meristem and root cap (cap protects apical meristem)
-RAM contains stem cells, protoderm (epidermal tissues), ground meristem (ground tissue), and procambium (makes vascular tissue)
-Also produces protective root cap
-Root tips embedded in lubricating mucigel
-Zone of elongation
-Cells extend by water uptake
-Zone of maturation
-Root cell differentiation and tissue specialization
-Identified by presence of root hairs (water and mineral uptake) absent from older regions
Term
Root System Specialization
Definition
-Eudicots often have taproots (one main root with many branches)
-Monocots have fibrous roots (no main roots, many equivalent branches from base of stem)
-Other types of roots
-Prop root-originate from stem, support the plant
-Buttress roots-broad supporting structures in shallowly rooted trees
-Pneumatophores-upward directed appendage, allows for gas exchange
-Fleshy storage roots-carrots, sugar beets
Term
Overview of Plant Behavior
Definition
-Plants engage in more active behaviors than generally given credit for
-Many different types of stimuli can lead to a variety of behavioral/developmental responses in plants
Term
Plant Responses to Internal and External Stimuli
Definition
-Internal
-Electrical signals-action potentials particularly important in rapid plant movements
-Chemical signals-hormones control plant cell, tissue and, organ development and allow plants to respond to environmental stimuli
-External
-Light, atmospheric gases (CO2 and water vapor), temperature, touch, wind, gravity, water, and rocks, and soil stimuli
-Herbivores, pathogens, organic chemicals from neighboring plants, and beneficial or harmful soil organisms
-Agricultural chemicals including hormones
Term
Plant signal transduction
Definition
-Process in which a cell perceives a signal, switching on an intercellular pathway that leads to intercellular responses
-Involves:
-Receptors or sensors
-Proteins that become activated when they receive a specific type of signal
-Messengers or second messengers
-Transmit messages from many types of activated sensors to effector molecules
-Calcium ions common
-Effectors
-Molecules that directly influence cellular responses
-Often involve activation or repression of gene expression
-Signal transduction ends when an effector causes a cellular response
Term
Plant Hormones
Definition
-About a dozen small molecules synthesized in metabolic pathways
-Auxins, cytokinins, gibberellins, ethylene, abscisic acid, and brassinosteroids
-One hormone may have multiple effects
-Different concentrations or combinations can produce distinct responses
Term
Auxins
Definition
-Master plant hormone
-Influence plant structure, development, and behavior in many ways:
-Apical-basal polarity of plant body
-Important in the development of vascular tissues
-Alter pattern of growth and development in response to environment
Term
Auxin transport
Definition
-Produced primarily in apical shoot tips and young leaves
-Directionally transported
-May enter cells by diffusion
-AUX1 plasma membrane protein (Auxin influx carrier) at apical cell end
-PIN proteins transport auxin out (auxin efflux carriers) at basal or lateral surfaces of cells
-Polar transport-auxin flows down in shoots and into roots
-Differences in localization of carriers explains variation in auxin concentration within plants
Term
Auxin Effects
Definition
-Many effects on practical important to humans
-Seedless fruit production
-Stimulate flower ovaries to mature into fruits
-Retardation of premature fruit drop
-Used as commercial rooting compound
-Pinching topmost shoots alter new outgrowth, produces bushy plants
Term
Role of Auxin in Phototropism
Definition
-1880s-Darwin and son were the first to publish results of experiments on phototropism
-Shoots of seedlings left uncovered grew toward the light
-Shoots of seedlings with covered or removed tips did not bend toward the light.
-Seedling shoot tips transmitted some "influence" to lower shoot portions.
Term
Went and Briggs' Experiment on the Role of Auxin in Phototropism
Definition
-Shoot tips of oat seedlings cute off and placed on agar blocks.
-Four treatments to decapitated shoots:
-Placed auxin-laden agar blocks off-center on some
-Placed auxin-laden blocks evenly onto others
-Placed plain agar blocks off-center on some
-Left them uncapped
-Auxin application could substitue for directional light stimulus
-Asymmetrical auxin distribution mechanism causing bending
Term
Cytokinins
Definition
-promote cell division in plant shoots and roots
Term
Gibberellins
Definition
-influence various development processes, including stem elongation, germination, dormancy, flowering, and fruit maturation and senescence
Term
Ethylene
Definition
-Stimulates or regulates the ripening of fruit, the opening of flowers, and the abscission (or shedding) of leaves.
-If you put a banana in a bag, it will ripen faster.
Term
Stress Hormones
Definition
-Help plants respond to environmental stresses such as flooding, drought, high salinity, cold, heat, and attack by microorganisms and herbivores
-Abscisic acid
-Brassinosteroids
-Salicylic acid
-Systemin
-Jasmonic acid
-Nitric oxide
Term
Herbivore attack
Definition
-Structural barriers help to reduce infection and herbivore attack
-Herbivore attack
-Wide variety of chemical defenses
-Plant responses to Jasmonic acid can cause synthesis of chemicals that are repulsive to herbivore
-Can also cause release of chemicals attract predators of their attackers and/or cause defensive response in neighboring plants
Term
Microbial Pathogen Attack
Definition
-Chemicals produced by bacterial and fungal pathogens elicit response
-Example: Systemic acquired resistance (SAR)
-Localized response can result in the production of alarm signals that travel to noninfected regions of a plant and induce widespread resistance to diverse pathogens
-Jasmonic acid
-May cause production of defensive enzymes or tannins (toxic to certain microorganisms)
-Volatile compounds may be transmitted to nearby plants, initiating defense response
Term
Gravitropism
Definition
-Growth in response to the force of gravity
-Shoots are said to be negatively gravitropic
-Most roots are positively gravitropic
-Statocytes contain starch-heavy plastids called statoliths
-Heavy statoliths sink, causing changes in calcium ion messengers, including lateral auxin transport
-Changes direction of root or shoot growth
Term
Thigmotropism
Definition
-Touch responses
-Roots encounter rocks as they grow down
-Touch response temporarily supersedes their response to gravity
-Roots grow horizontally until they get around the barrier, then downward growth in response to gravity resumes
-Grasping behavior of vine tendrils
-More rapid responses ("nastic responses" or "thigmonasty"), caused by changes in water content of cells
-Leaves with pulvinus to become limp when touched
-Electrical impulse transmitted, causes pumping of ions, loss of plant cell turgor pressure
Term
Photoreceptors
Definition
-Respond to light absorption by switching on signal transduction
-Results in sun tracking, phototropism, flowering and seed germination
-Examples:
-Phytochromes are red light receptors involved in timing or germination, flowering
-Blue-light receptors
-Cyptochromes help young seedlings determine if light environments bright enough for photosynthesis
-Phototrponin- main blue-light sensor in phototropism
-Becomes phosophorylated when exposed to blue light, converting light signal to a chemical signal
Term
Photoperiodism and Flowering
Definition
-Flowering plants can be classified as long-day, short-day, or day-neutral plants according to the way of their flowering responds to night length
-Long-day plants-flower in spring or early summer, when the night period is shorter than a defined period
-Short-day plants-flower only when the night length, as long as day length meets the minimal requirements for plant growth
-Day-neutral plants-flower regardless of the night length, as long as day length meets the minimal requirements for plant growth
Term
Phytochromes and Photoperiodism
Definition
-Phytochromes-red and far-red-light receptors
-Flips back and forth between 2 conformations
-Pfr-conformations that only absorbs far-red-light and activates cellular responses
-Moves from cytoplasm to nucleus, impacting gene regulation
-Absorption of far-red light causes conversion of Pr (inactive)
-When left in the dark (or exposed to far-red light), Pfr transforms to red light absorbing Pr (inactive)
-Pr can only absorb red light and cannot activate cellular responses
-Red light converts from Pr to Pfr.
Term
Nutrient
Definition
-Beneficial substance metabolized by or incorporated into an organism
-Deficiency symptoms may develop in plants that receive too little required nutrients
-Scarcity of nutrients may:
-Select for adaptations that help in acquisition
-Or trigger adaptive changes that aid in nutrient acquisition
-Certain nutrients can be limiting factors-carbon dioxide, water, and other mineral nutrients can limit growth
Term
Essential Nutrients
Definition
-Substances needed by plants in order to complete their reproductive cycle
Term
Macronutrients
Definition
-Required in amounts of at least 1g/kg of plant dry matter
Term
Micronutrients or trace elements
Definition
-Required in amounts at or less than 0.1 g/kg per day
Term
Carbon Dioxide
Definition
-Macronutrient
-Most of play dry mass originates from CO2 (carbon fixation)
-Often, plants do not obtain enough CO2 for maximal photosynthesis
-Modern atmospheric CO2 is only 350 mill/L (0.035% of atmospheric content)
-1000 mil/L of CO2 is required to saturate photosynthesis
Term
Water
Definition
-a macronutrient
-Typically 90% of weight in living plants
-Essential for several reasons
-As a nutrient, source of most hydrogens and some oxygen in organic compounds (reduced carbon compounds)
-Important for metabolic biochemical reactions (e.g. hydrolysis)
-Solvent for other mineral nutrients
-Main transport medium in plants
Term
Additional Plant Nutrients
Definition
-Macronutrients-nitrogen, potassium, calcium, magnesium, phosphorous, and sulfur
-Micronutrients-chlorine, iron, manganese, boron, zinc, sodium, copper, molybdenum, and nickel
-When plants lack essential nutrients they displat deficiency symptoms
-Failure to reproduce, tissue death, and changes in leaf color
-Chlorosis-yellowing of leaves
-Each nutrient has specific roles to play.
Term
Nitrogen
Definition
-Frequently limits plant growth
-Large amounts required for synthesis of amino acids, nucleotides, alkaloids, and many others
-Largest component in plants by weight after carbon, oxygen, and hydrogen
-Although earth's atmosphere is 78% nitrogen (N2), plants cannot use this form
-Nitrogen must occur in a "fixed" form such as ammonia (NH3), ammonium ion (NH4+), or nitrata ion (NO3-).
-Microorganisms oxidize ammonia to nitrate.
-Nitrate is the most common form of most fixed nitrogen enters plant
-Plasma membrane transported proteins import nitrate into root cells
-Transported in xylem
-Can be stored in vacuoles
Term
Fixing Atmospheric Nitrogen
Definition
-Takes nitrogen out of its gaseous form and puts it into a chemical form
-Much of fixed nitrogen in soil is recycle from compounds in other organism
-New fixed nitrogen can be added by lightning, fire, air, pollution, and biology and industrial fixation
-Nitrogen fixation-atmospheric N2 combined with H to give NH3
-Most biological nitrogen fixation by certain prokaryotes
-By many types of Cyanobacteria
-Other nonphotosynthetic bacteria also fix nitrogen
-Symbionts transfer nitrogen directly to plant cells
-All nitrogen-fixing prokaryotes utilize large amounts of ATP and nitrogenase to fix nitrogen
Term
Plant Adaptations that Increase Nutrient Supply
Definition
-Highly branched roots
-More or longer root hairs
-Fungal symbiotic associations
-Bacterial symbiotic association
-Capture of animals by carnivorous plants
-Parasitic associations
Term
Symbiotic Associations that Aid in Nutrient Acquisition
Definition
-Mycorhizzal associations
-About 90% of seed plants have fungal symbiotic associations
-Fungi live within root tissues or envelop root surfaces
-Fungi obtain organic food from plant while fungi supplies water and mineral nutrients
-Very efficient way to harvest water and mineral (especially phosphorus) from a larger volume of soil
Term
Plant-prokaryote symbioses
Definition
-Provides fixed nitrogen
-Some bacterial symbiotes live within plant cells or tissues
-Plants provide organic nutrients to bacteria
-Bacteria supplies plants with more fixed nitrogen than they could get from soil
-Legume-Rhizobia Symbioses
-Certain bacteria live in root cells of legumes
-Rhizobia can live independently but only fix nitrogen inside root nodules
-Nodule formation involves chemical signals between rhizobia and host plant
Term
Plant Transport Overview
Definition
-Root system absorbs water and dissolved minerals from the soil
-Shoot system uses these materials together with CO2 during photosynthesis to produce sugar needed by roots and for overall plant growth and reproduction
-Xylem transports water and dissolved minerals
-Phloem transports dissolved organic substances
-Cells uses active and passive processes to promote transport
Term
Cellular Water Movement in Plants
Definition
-Water content of plants' cells depend on:
-Osmosis (into cells)
-Turgor pressure-hydrostatic pressure that increases as water enters plant cells
-Cell walls restrict the extent to which cells can swell
-Turgidity
-Turgid plant has a cytosol/vacuole full of water and plasma membrane pushes up against the cell wall
-"Plasmoylzed" cell has lost so much water that turgor pressure is lost, cell membrane pulls away from cell wall
-Flaccid cell is between the 2 extremes
Term
Empirical Thought
Definition
-relies on observation to form an idea or hypothesis, rather than trying to understand life from a nonphysical or spiritual point of view.
-Encouraged scholars to look for the basic rationale behind a given object or phenomenon.
Term
Inheritance of Acquired Characteristics
Definition
-The behavioral changes modified by traits were inherited by offspring.
-Example: Giraffes develop their elongated necks and front legs by feeding on high tree leaves.
Term
Transitional Form
Definition
-Provides a link between earlier species and many later species
-Example: fishapod
Term
Analogous Structures or Convergent Traits
Definition
-Similar characteristics that are a result of convergent evolution
Term
Selective Breeding
Definition
-Refers to programs and procedures designed to modify traits in domesticated species
-Also known as artificial selection
Term
Homologous Structures
Definition
-Traits that are considered to be derived from a common ancestor.
Term
Vestigial Structures
Definition
-Anatomical features that have no apparent function but resemble structures of their presumed ancestors.
Term
Homologous Genes
Definition
-Occurs when two genes are derived from the same ancestral gene
Term
Orthologs
Definition
-Genes that are homologous yet from different species
Term
Paralogs
Definition
-Two or more homologous genes found within a single species
Term
Gene family
Definition
-Consists of two or more copies of paralogous genes within the genome of a single organism.
Term
Exon Shuffling
Definition
-A type of mutation that creates many new genes during the evolution of eukaryotic species.
-An exon and the flanking introns are inserted into the gene, producing a new gene that encodes a protein with an additional domain.
-May also involve the duplication and rearrangement of exons
-Results in novel genes that express proteins with diverse functional modules.
Term
Horizontal Gene Transfer
Definition
-Involves the exchange of genetic material among different species
-Process by which species accumulate genetic changes
-Enables species to acquire new traits that foster the evolutionary process.
Term
Macroevolution
Definition
-The evolutionary changes that create new species and groups of species
-Occurs by the accumulation of microevolutionary changes, those that occur in a single gene
Term
Phylogenetic Species Concept
Definition
-The members of a single species are identified by having a unique combination of characteristics.
Term
Reproductive Isolation
Definition
-Prevents one species from successfully interbreeding with other species.
Term
Biological Species Concept
Definition
-A species is a group of individuals whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species
Term
Evolutionary Species Concept
Definition
-A species is derived from a single lineage that is distinct from other lineages and has its own evolutionary tendencies and historical fate
Term
Lineage
Definition
-The genetic relationship between an individual or group of individuals and its ancestors
Term
Ecological Species Concept
Definition
-Each species occupies an ecological niche
-Within their own niche, members of a certain species compete with one another for survival
Term
Ecological Niche
Definition
-The unique set of habitat resources that a species requires, as well as its influence on the environment and other species
Term
Prezygotic Mechanisms
Definition
-Prevent the formation of a zygote
Term
Postzygotic Mechanisms
Definition
-Block the development of a viable and fertile individual after fertilization takes place
Term
Interspecies Hybrid
Definition
-The offspring of two different species
Term
Anagenesis
Definition
-A single species is transformed into a different species over the course of many generations
-Evolutionary mechanisms cause the characteristics of the species to change.
Term
Cladogenesis
Definition
-Involves the division of a species into two or more species.
-Related to geographic isolation
Term
Adaptive Radiation
Definition
-A single ancestral species has evolved into a wide array of descendant species that differ greatly in their habitat, form, or behavior.
Term
Gradualism
Definition
-Suggests that each new species evolves continuously over long spans of time
-Large phenotypic differences that produce new species are due to the accumulation of many small genetic changes
Term
Punctuated Equilibrium
Definition
-Advocated in the 1970s by Niles Eldredge and Stephen Jay Gould
-Suggests that the tempo of evolution is more sporadic.
-Species exist relatively unchanged for many generations.
Term
Evolutionary Development Biology
Definition
-Evo-devo
-Compares the development of different organisms in an attempt to understand ancestral relationships between organisms and the developmental mechanisms that bring about evolutionary change.
Term
Paedomorphosis
Definition
-Common among salamanders
-The retention of juvenile traits as adults
-These species do have the ability to reproduce successfully.
Term
Allometric Growth
Definition
-The pattern whereby different parts of the body grow at different rates with respect to each other
Term
Seeds
Definition
-Reproductive structures produced by flowering plants and other seed plants, usually as the result of sexual reproduction
-Contain embryos that develop into young plants when seeds germinate.
Term
Alternation of Generations
Definition
-Flowering plants produce relatively large sporophytes and microscopic gametophytes that grow and develop within flowers.
-The alternation of the gametophyte and sporophyte generations.
Term
Growth
Definition
-The increase of weight and size.
Term
Development
Definition
-an increase in the number of organs, accompanied by differentiation of tissues and specialized cells having distinctive structure and function.
Term
Tissue
Definition
-Groups of adjacent cells that have particular functions
-Produced in meristems
Term
Cotyledons
Definition
-Embryonic leaves known as seed leaves
Term
Vegetative Growth
Definition
-The production of new tissues by the SAMs and RAMs during seedling development and growth of mature plants
Term
Indeterminate growth
Definition
-SAMs continuously produce new stem tissues and leaves as long as conditions remain favorable.
-Explains how very large plants can develop seedlings.
Term
Palisade Parenchyma
Definition
-Consists of closely packed, elongated cells adapted to absorb sunlight efficiently.
Term
Spongy Parenchyma
Definition
-Contains rounder cells separated by abundant air spaces
-The air spaces foster CO2 absorption and O2 release by leaves.
Term
Mesophyll
Definition
-The palisade and spongy parenchyma
Term
Expansins
Definition
-Unzip cross-linking cell-wall polysaccharides from cellulose microfibrils, so that the cell wall can stretch.
-The cells enlarge, often by elongating in a particular direction.
Term
Gibberellic Acid
Definition
-Stimulates both cell division and cell enlargement, causing young leaves to grow larger.
-Produce by leaf primordia when there is an absence of KNOX proteins
Term
Outer bark
Definition
-The protective layers of mostly dead cork cells that cover the outside of woody stems and roots.
Term
Inner bark
Definition
-Conducts most of the sugar transport in a large tree
-A thin layer of phloem
Term
Mucigel
Definition
-Cover root tips
-Composed of water bound by sticky polysaccharides secreted by root-tip epidermal cells.
-Lubricates roots, aiding in their passage through the soil.
-Helps in water and mineral absorption, prevents root drying, and provides an environment hospitable to beneficial microbes.
Term
Zone of Maturation
Definition
-Where most root cell differentiation and tissue specialization occur
-Located about the zone of elongation
-Can be identified by the presence of numerous microscopic hairs that emerge from the root epidermis.
Term
Root hairs
Definition
-Specialized epidermal cells that can be as long as 1.3 cm.
-Root hair plasma membranes are rich in transport proteins that use ATP to selectively absorb materials from the soil.
Term
Root cortex
Definition
-The region of the ground parenchyma at which the epidermis of mature roots encloses
-Often rich in starch and thus serve as a food storage site for plants.
-The root cortex of some plants contain intracellular air spaces that arise from apoptosis and provide routes for oxygen diffusion within the root.
Term
Pericycle
Definition
-Encloses the root vascular tissue
-A cylinder of tissues that have cell division capacity
-Produces lateral roots that force their way through the cortex to the surface
Term
Behavior
Definition
-Response to stimuli
-Example: Plant movement, growth and development in response to stimuli
Term
MicroRNAs
Definition
-miRNAs
-Mobile chemical signals control plant cell, tissue, and organ development and allow plants to respond to environmental stimuli.
Term
Phenotypic Plasticity
Definition
-Individual members of the same plant species that experience different environmental conditions may display considerable variation in structure or behavior
Term
Polar transport
Definition
-The process of auxin primarily flowing downward in shoots and into roots
Term
Plant tissue culture
Definition
-Used commercially to produce thousands of identical plants having the same desirable characteristics.
-Begins with the pieces of stem, leaf, or root that have been removed from a plant, and their surfaces are sterilized to prevent growth of microbes.
Term
Cryptochromes
Definition
-Help young seedlings determine if their light environment is bright enough to allow photosynthesis.
-If the light environment is not bright enough, then seedings will continue to elongate in the soil, toward the light.
Term
Statoliths
Definition
-Starch-heavy plastids that enable both roots and shoots to detect gravity
-Statoliths make up statocytes.
Term
Aerenchyma
Definition
-Aerenchyma formation involves the action of ethylene, which leads to programmed cell death, followed by cell collapse.
-The tissue in which internal, snorkeling-like airways that allow more oxygen to flow from the shoots to roots is produce.
Term
Heat shock proteins
Definition
-Proteins that help to protect proteins from heat damage and refold proteins to their functional state.
Term
Vernalization
Definition
-Plant adaptation to cold
-Allows plants that grow best in the cold to flower only in the warm season, after unfavorable winter conditions have passed.
-Example: wheat, barely, and other cereals
Term
Elicitors
Definition
-Produced by bacterial and fungal pathogens
-Promote virulence
Term
Virulence
Definition
-The infection of plant tissues
Term
Avirulence Genes
Definition
-Avr genes
-encode virulence-enhancing elicitors
Term
Resistance Genes
Definition
-R genes
-Many alleles of R genes occur in plant populations, providing plants with a large capacity to cope with many types of pathogens.
-Most encode proteins that function as receptors for elicitors.
Term
Hypersensitive Response
Definition
-HR
-Occurs when a plant recognizes the elicitors released by a pathogen and responds in such a way that the disease symptoms are limited.
Term
Systemic Acquired Resistance
Definition
-SAR
-A type of plant immune system
-Uses the same type of long-distance signaling process that is associated with herbivore attacks.
-At or near the wound, the production of systemin induces the production of jasmonic acid in nearby vascular tissues.
Term
Chlorosis
Definition
-A common mineral deficiency symptom, because many nutrients are needed for chlorophyll production
-The yellowing of leaves
Term
Fertilizers
Definition
-Soil additions that enhance plant growth by providing essential elements
-Also sold for use in enriching garden soil or growing houseplants.
Term
Soil horizons
Definition
-Layers of natural soils
-From top: horizon topsoil, horizon subsoil, horizon soil base, bedrock.
Term
Humus
Definition
-The organic constituents of soils
-Largely derived from plant detritus, although animal wastes and decayed animal bodies also contribute to the organic content of soils.
Term
Detritus
Definition
-The partially decomposed remains of plants
Term
Weathering
Definition
-The physical and chemical breakdown of rock
-Derive inorganic materials
Term
Leaching
Definition
-Dissolution and removal of inorganic ions as water percolates through materials.
Term
Organic Farming
Definition
-Production of crops without the use of inorganic fertilizers, growth substances, and pesticides.
-Examples: manure and compost
Term
Industrial Nitrogen Fixation
Definition
-A human activity
-Produce nitrogen fertilizers applied to crops
Term
Nitrogenase
Definition
1. Nitrogenase binds to a molecule of nitrogen gas
2. The bound nitrogen is reduced by the addition of two hydrogen atoms
3. Two molecules of ammonia are released and dissolve in cell water to form ammonium ions
Term
Mineralization
Definition
-The general process by which phosphorus, nitrogen, CO2, and other minerals are released from organic compounds
Term
Bacteriods
Definition
-The modified rhizobia present in mature nodules
Term
Passive Transport
Definition
-Movement of materials into or out of cells down a concentration gradient without the expenditure of energy in the form of ATP.
-Occurs by passive diffusion or facilitated diffusion
Term
Passive diffusion
Definition
-The movement of a solute through a phospholipid bilayer down a gradient.
Term
Facilitated Diffusion
Definition
-The transport of molecules across plasma membranes down a concentration gradient with the aid of membrane transport proteins.
Term
Transporters
Definition
-Proteins that transport molecules by binding them on one side of the membrane and then changing conformation so the molecule is released to the other side of the membrane.
-Increase the rate at which specific mineral ions and organic molecules are able to enter plant cells and vacuoles.
Term
Channels
Definition
-Membrane pores formed by proteins that allow movement of ions and molecules across membranes
Term
Cotransport
Definition
-Symport
-Transport of two substances in the same direction across a membrane
Term
Solute potential
Definition
-Osmotic potential
-Component of water potential due to the presence of solute molecules
-Proportional to the concentration of solutes in a solution.
Term
Pressure potential
Definition
-Component of water due to hydrostatic pressure
-The value for pressure potential can be either positive or negative.
Term
Relative water content
Definition
-RWC
-Often used to gauge the water content of a plant organ or entire plant
-Integrates the water potential of all cells within an organ or plant and is thus a measure of relative turgidity.
-Measurements of RWC can be used to predict a plant's ability to recover from the wilted condition.
-An RWC of less than 50% spells death for most plants, but some plants can tolerate lower water content for substantial time periods.
Term
Osmotic Adjustment
Definition
-Process in which plants often increase the solute concentrations of their cell cytosol
-By increasing the concentration of solutes inside cells, cold-resistant plants prevent water from moving out of their cells when ice crystal formation in intercellular spaces lower the water potential outside cells.
Term
Halophytes
Definition
-Plants that are able to grow in salty habitats, including coastal salt marshes.
-Example: Perennial glasswort
-Display adaptations that help rid their bodies of excess salts
-Some halophytes excrete salt from root surfaces, while others transport excess salt to their leaf epidermal cells.
Term
Vascular transfer cells
Definition
-Abundant at leaf gaps.
-Have extensive inward cell-wall protrusions
Term
Root pressure
Definition
-The process by which some plants are able to refill embolized vessels
-
Term
Guttation
Definition
-As the water rushes upward, it can dislodge air bubbles or dissolve them, thereby reversing embolism.
Term
P protein
Definition
-Phloem protein
-Masses of this protein congeal along sieve plates, preventing loss of phloem sap.
-Protein involved in short-term wound response
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