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Exam 2
Plants
107
Biology
Undergraduate 1
04/24/2012

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Term
Tissue Level Transport
Definition
1. Transmembrane Transport
2. Symplastic Transport
3. Apoplastic Transport
Term
Transmembrane Transport
Definition
1. Export of material from one cell into the intercellular space, followed by import of the same substance by an adjacent cell
2. Movement of auxin
Term
Symplastic Transport
Definition
1. Movement of a substance from the cytosol of one cell to the cytosol of an adjacent cell via plasmodesmata
2. Transport through plasmodesmata occurs primarily by diffusion
3. "Symplast" formed by all of a plant's cells & plasmodesmata
4. Connected cytoplasm-continuous connections of all cytoplasms by plasmodesmatas
Term
Plasmodesmata
Definition
Microscopic channels which traverse the cell walls of plant cells-stretches between 2 cytoplasms
Term
Apoplastic Transport
Definition
1. Movement of solutes through cell wall material, spaces between cells: material outside the cell can find a way to diffuse into the cell
2. Apoplast-continuum of water-soaked cell walls & intercellular spaces
3. Short-distance transport
Term
Tissue Level Transport Pathways in Roots
Definition
1. Both symplastic & apoplastic transport play important roles in mineral nutrient transport through the outer tissues of roots
2. Apoplastic transport moves soil water and dissolved minerals through root epidermal and cortex tissues
3. Apoplastic movement stops at root endodermis-barrier between root cortex & central core
4. Casparian strips prevent apoplastic transport into root vascular tissues-only symplastic movements allowed: epidermis is caulked to gum up area between cells
5. Endodermal plasma membranes possess specific channels & transporters for essential mineral nutrients
6. Root endodermis functions as a molecular filter that allows the passage of beneficial solutes that have entered from the symplast or have been specifically transported into endodermal cytosol through specific transport channels
Term
Xylem loading
Definition
large amounts of water enter the long-distance conducting cells of the xylem, carrying solutes along
Term
Long-Distance Transport in Plants
Definition
1. Bulk or mass flow-mass movement of liquid caused by pressure, tension, gravity, capillary action, or a combo of these
2. Liquids and dissolved solutes move faster by bulk than diffusion
3. Movement of fluid in xylem and phloem
Term
Movement of fluid in xylem and phloem
Definition
1. xylem water flow driven upward
2. phloem movement occurs from regions of high to low solute concentration
Term
Flowering plant xylem contains several types of specialized cells
Definition
1. Xylem parenchyma cells alive, not directly involved in long-distance
2. Thick-walled supportive fibers may be alive or dead at maturity; provide structural support
3. Tracheids & vessel elements are specialized water-conducting cells and are always dead and empty of cytosol when mature (gymnosperms contain only tracheids)
Term
Tracheids
Definition
1. Long & narrow with slanted ends
2. Lignin-containing (water impermeable, secondary wall)
3. Pits
Term
Pits
Definition
Nonlignified holes allow water to flow from one tracheid to another
Term
Vessels & Vessel Elements
Definition
1. Vessel elements are aligned in pipeline-like files known as vessels
2. Gives greater capacity for bulk flow to flowering plants
3. Water flows faster through vessels than tracheids
Term
Cohesion-Tension Theory
Definition
Plants expend little or no energy on bulk flow through xylem
Term
Forces that power xylem bulk flow
Definition
1. Adhesion
2. Water is cohesive due to strong hydrogen bonding
3. Sun's energy indirectly powers transpiration
Term
Adhesion
Definition
water stick to lignified walls of xylem vessels
Term
Sun's energy indirectly powers transpiration
Definition
1. Heat from sunlight
2. Use of water in photosynthesis
Term
Heat from sunlight
Definition
1. Causes evaporation at leaf surfaces, 90% of water is taken in is lost by evaporation
2. Tension exerted on water by evaporation at plant's surface pulls a continuous stream of water from the soil
Term
Use of water in photosynthesis
Definition
formation of reduced carbon compounds (<10% of water uptake)
Term
Adaptations to reduce Transpirational water loss
Definition
1. Stomatal movements
2. Leaf abscission or leaf drop
Term
Stomatal movements
Definition
1. Guard cells close to conserve water when it is not needed for photosynthesis
2. Blue light stimulates active guard cell ion uptake, water flows in, cells expand and stomata opens
3. At night, ions pumped out, cell deflates and stomata closes
Term
Leaf abscission or leaf drop
Definition
1. Occurs normally to prevent water stress or to temperature or light changes
2. Particularly valuable adaptation for desert plants and angiosperm trees of seasonally cold habitats
3. Ethylene stimulates formation of abscission zone with separation layer and underlying protective area
Term
Phloem
Definition
1. Mature phloem tissues remain alive & retain at least some cytoplasmic components
2. Phloem works under positive hydrostatic pressure, unlike xylem, which is under tension (negative pressure)
3. Composed of supporting fibers, parenchyma cells, sieve-tube elements (cells), & adjacent companion cells
Term
Sieve-tube elements
Definition
1. Sieve-tube elements loses its nucleus & most of the cytoplasm to reduce obstruction to bulk flow
2. Companion cell supplies mRNA & proteins to sieve tube element via plasmodesmata
Term
Phloem loading
Definition
1. Companion cells play an essential role in conveying sugars to sieve-tube elements for long-distance transport
2. Sucrose (disaccharide) used for most long distance transport
Term
2 types of phloem loading
Definition
1. Symplastic loading
2. Partial Apoplastic loading
Term
Symplastic loading
Definition
1. Many woody plants transport sucrose from sugar producing cells of the leaf, to companion cells & then to sieve-tube elements via plasmodesmata
2. Does not require ATP; facilitated diffusion
Term
Partial Apoplastic loading
Definition
1. Load sugar into sieve-tube elements or companion cells from intercellular spaces, often up a concentration gradient by active transport
2. ATP must be used to move the sugar across the plasma membrane into a companion cell or sieve-tube element
Term
Translocation of Phloem Sap (bulk transport system)
Definition
1. Phloem transport driven by differences in turgor pressure that occur between cells of a sugar source and sugar sink
2. Source and sink tissues may change during the seasonal cycle
3. Because of the changes in source and sink tissues, the direction of phloem flow may change with seasons
Term
Source
Definition
tissue that is producing & releasing sugar
Term
Sink
Definition
tissue that is actively taking & storing source
Term
Translocation
Definition
bulk transport from source to sink tissue
Term
Source & sink tissues may change during the seasonal cycle
Definition
1. Photosynthetic leaf mesophyll is the main sugar "source" during the time of the year when the leaves are actively photosynthesizing
2. Roots are the main "source" when new growth, leaf formation occurs in the spring
3. Roots, developing leaves, seeds, & fruits are sugar "sinks" at different times of the year
Term
Pressure flow hypothesis
Definition
Ernst, Munch, German plant physiologist, 1930
1. Sieve-tube elements near source tissues have comparatively high solute content due to movement of sugars from source
2. Water tends to rush into them from adjacent xylem, thereby building hydrostatic pressure
3. Vessel elements near "sink" tissues have lower solute concentration
4. Hydrostatic pressure overcomes reduced solute pressure & water moves into adjacent xylem
Term
Alternation of Generations-Review
Definition
2 multicellular life cycle stages
1. Diploid, spore-producing by meiosis
2. Haploid, gamete-producing by mitosis
Term
Flowers
Definition
1. Reproductive shoot-a stem branch that produces reproductive organs instead of leaves
2. Flower organs produced by shoot apical meristems
3. Flower organ functions
Term
Flower organs produced by shoot apical meristems
Definition
1. Sepals
2. Petals
3. Stamens
Term
Sepals
Definition
1. Often function to protect unopened flower bud
2. After the flower blossoms, the sepals help support the petals
Term
Petals
Definition
Usually serve in attraction of pollinators
Term
Stamens
Definition
1. Produce male gametophytes & foster their early development
2. Filament topped by anther
3. Diploid cells undergo meiosis producing 4 tiny, haploid spores (micropores)
4. At the time of dispersal, the microspores is a two-or-three-celled male gametophyte produced by mitotic division
5. Each male gametophyte (pollen grain) develops a tough outer wall
6. During a later phase of development, a mature male gametophyte produces sperm cells
Term
Anther
Definition
a group of 4 microsporangia
Term
Early male gametophyte development
Definition
1. Each microscopic nucleus undergoes mitosis to form male gametophyte
2. Generative cell divides to produce 2 sperm cells
3. Tube cell will form pollen tube
Term
Pollen wall development
Definition
1. Each plant species has distinctive shape to pollen wall
2. Composed largely of sporopollenin (physical strength)
Term
Carpels
Definition
1. Vase-shaped structures that produce, enclose, & nurture female gametophytes and mature male gametophytes
2. Contain veins of vascular tissue that deliver nutrients from the parent sporophyte to the developing gametophytes
3. Flower contains one or more carpels that form a pistil
4. Carpel composed of stigma, ovary, & style
Term
Ovary
Definition
produces & nourishes one or more ovules
Term
Ovules
Definition
spore-producing structure enclosed in integuments (megasporangium)
Term
Ovaries & Ovules
Definition
1. Within ovule, diploid cell produces 4 megaspores by meiosis (3 die)
2. Surviving megaspore generates female gametophyte by mitosis
Term
Female gametophyte
Definition
1. Each ovule produces a single female gametophyte by mitosis of megaspore
2. Often possess 7 cells & 8 nuclei
Term
Female gametophyte often possess 7 cells & 8 nuclei
Definition
1. Egg cell lies between 2 synergids
2. 3 antipodial cells
3. Central cell has 2 nuclei
Term
Fertilization
Definition
1. Development of the mature male gametophyte
2. Pollen Germination
3. Double Fertilization
Term
Development of the mature male gametophyte
Definition
1. When pollen grains land on stigma, stigma allows only appropriate genotype to germinate
2. Pollen tube grows through micropyle and delivers sperm to female gametophyte
3. Results in double fertilization
Term
Pollen Germination
Definition
1. Pollen grain germinates by taking up water & producing a pollen tube
2. Pollen generative nucleus usually divides by mitosis to produce 2 sperm cells
3. Upon rehydration a pollen tube extends into the between cells of the style
4. To deliver sperm to egg cells, the tube must grow from the stigma, through the style, to the ovule
5. A pollen tube conveys 2 sperm cells to the female gametophyte
6. Tip growth controlled by tube cell nucleus
7. New cytoplasm & cell wall material added to tip of elongating cell
8. Callose plugs concentrate components of the cytoplasm at the tip
9. Tube enters through micropyle of the ovule
Term
Double Fertilization
Definition
1. One of the 2 sperm cells fertilize the egg to produce the diploid zygote
2. Other sperm fuses with 2 nuclei located in central cell
Term
Other sperm fuses with 2 nuclei located in central cell
Definition
Produces endosperm by mitosis
Term
Produces endosperm by mitosis
Definition
1. Endosperm develops as a nutritive tissue, usually triploid chromosome number
2. Supplies nutritional needs for developing embryo and often seedling
3. Rich in protein, lipid, carbohydrate, vitamins, & minerals
4. Nutrients in endosperm comes from parent sporophyte by apoplastic transport
5. Eudicots store nutrients from endosperm in cotyledons-mature seeds contain little to no endosperm
6. Monocots retain considerable endosperm in the mature seed
Term
Embryo
Definition
A young, multicellular, diploid sporophyte
Term
Tough seed coat
Definition
Produced by sporophyte integuments
Term
Seeds
Definition
Contain tissues from 2 sporophyte generations
Term
Embryo Development
Definition
1. Embryogenesis is the development of single celled zygotes by mitosis
2. First cell division is unequal
3. Suspensor disappears and older embryos rely on endosperm
Term
First cell division is unequal
Definition
1. Establishes apical-basal polarity
2. Smaller cell develops into embryo
3. Larger cell develops into suspensor that channels nutrients & hormones to young embryo
Term
Distinction between eudicot & monocot embryos
Definition
1. Young eudicot embryos are spherical but become heart-shaped as cotyledons develop; shoot meristems forms between cotyledons
2. Mature monocot embryos are cylindrical with a single cotyledon & a side notch where apical meristem forms
Term
All animals share similarities in the ways in which they:
Definition
1. Exchange materials with their surroundings
2. Obtain energy from organic nutrients
3. Synthesize complex molecules
4. Reproduce themselves
5. Detect and respond to signals in their immediate environment
Term
What is unique/distinct about animals in comparison to plants?
Definition
1. No cell wall-impacts on developmental events & tissue/organ structure
2. No photosynthesis-acquisition of organic nutrients
3. Rapid, coordinated movement used in pursuit of food, or avoidance of predators
Term
Animal Tissues
Definition
1. Specialized cells of a given type cluster together to perform a specific function
2. 4 main categories
Term
Muscle
Definition
1. cells specialized to contract
2. 3 types in higher animals
Term
Skeletal Muscle Tissue
Definition
attached to bone or exoskeleton for locomotion, voluntary control
Term
Smooth Muscle Tissue
Definition
surrounds hollow tubes & cavities for propulsion of contents, involuntary control-e.g. blood vessels, most digestive organs
Term
Cardiac Muscle Tissue
Definition
only in the heart; involuntary control
Term
Nervous Tissue
Definition
1. Initiate & conduct electrical signals from one part of the animal's body to another
2. Electrical signals produced in one nerve cell may stimulate or inhibit other nerve cells
Term
Electrical signals produced in one nerve cell may stimulate or inhibit other nerve cells
Definition
1. Stimulate new electrical signals in adjacent neurons
2. Stimulate muscles to contract (nerve-muscle contraction)
3. Stimulate glands to release chemicals
Term
Epithelial Tissue
Definition
1. Sheets of densely packed cells
2. Specialized to protect, provide selective permeability, secrete or absorb materials
3. Rest on basal lamina or basement membrane
Term
Sheets of densely packed cells that
Definition
1. Cover the body or individual organs
2. Line the wall of body cavities
Term
Connective Tissue
Definition
1. Includes blood, adipose, bone, cartilage, loose & dense connective tissue
2. Oftentimes, much of connective tissue is composed of extracellular matrix around cells
Term
Functions of Connective Tissue
Definition
1. Provides scaffold for attachment
2. Protects & cushions
3. Mechanical strength
4. Transmit mechanical forces
Term
Organs
Definition
Composed of 2 or more kinds of tissues, organized together to provide coordinated function(s)
Term
Organ system
Definition
different organs work together to perform/regulate complex functions
Term
Organ systems frequently work together:
Definition
Spatial arrangement of organs into organ systems part of overall body plan
Term
Body fluids
Definition
1. 2 main compartments
2. Intracellular & extracellular fluid can be very different in solute composition
Term
2 main compartments of body fluids
Definition
1. Intracellular fluid
2. Extracellular fluid
Term
Intracellular fluid
Definition
inside cells
Term
Extracellular fluid
Definition
outside cells
Term
Circulatory Systems
Definition
1. Fluid transport systems designed for bulk transport within an animal's body
2. Closed Circulatory System
3. Open Circulatory System
Term
Closed Circulatory System
Definition
1. Fluid (blood) pumped within vessel system
2. Interstitial fluid
Term
Plasma
Definition
fluid portion of blood
Term
Blood cells
Definition
suspended in plasma
Term
Interstitial Fluid
Definition
fluid between cells outside vessels
Term
Open Circulatory Systems
Definition
1. Fluid (hemolymph) pumped but no distinction between pumped fluid & interstitial fluid
2. Typically no blood cells
Term
Animal Nutrition & Digestion
Definition
1. Basic similarities to animal cells lead to basic similarities in nutrition
2. However, different animal physiologies may lead to different nutritional demands
Term
Herbivores
Definition
eat plants
Term
Carnivores
Definition
consume animal flesh or fluids
Term
Omnivores
Definition
eat both plant & animal material
Term
What are nutrients?
Definition
any substance consumed by an animal that is needed for survival, growth, development, tissue repair, or reproduction
Term
Nutrients
Definition
1. Must be taken into the body
2. May need to be digested
3. May be used to make ATP
4. May be used as chemical building blocks, or as cofactors/coenzymes
Term
Nutrient Absorption
Definition
small molecules are often transported from area of digestion to animal's circulatory system
Term
ATP energy can be used for
Definition
1. Transport work
2. Mechanical work
3. Chemical work
Term
Animals often require
Definition
1. 5 categories of organic food molecules for complete nutrition
2. Inorganic nutrients (Minerals)
Term
5 categories of organic food molecules for complete nutrition
Definition
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
5. Vitamins
Term
Inorganic Nutrients (Minerals)
Definition
Phosphate, Potassium, Sodium, Calcium, Iron, etc.
Term
"Essential Nutrients"
Definition
Certain compounds cannot be synthesized from any ingested or stored precursor molecule
Term
Essential Amino Acids
Definition
1. 8 required by many animals
2. Cannot be synthesized by animal's own cells
3. Are not stored-need constant supply
4. Carnivores & omnivores readily obtain all essential amino acids in meat
5. Most plant food sources do not contain every essential amino acid in sufficient quantity to fully supply an animal's nutritional needs
Term
8 required Essential Amino Acids by many animals
Definition
Isoleucine, Leucine, Lysine, Methionine, Phenylalanine
Term
Essential Fatty Acids
Definition
1. Needed for building fats, phospholipids, steroid hormones
2. Certain polyunsaturated fatty acids cannot be synthesized by animal cells
3. Production of certain hormones requires intake of plant-derived fatty acids-Thromboxanes, Prostaglandins
4. Unsaturated fatty acids found primarily in plants
5. Strict carnivores obtain them from animal prey items
Term
Essential Minerals
Definition
Inorganic Ions
Term
Inorganic Ions
Definition
1. Many required in only trace amounts (mineral micronutrients)
2. Some required in larger amounts (mineral macronutrients)
Term
Mineral Micronutrients
Definition
1. Cobalt
2. Copper
3. Iodine
4. Arsenic
5. SIlicon
6. Selenium
7. Manganese
8. Molybdenum
Term
Mineral Macronutrients
Definition
1. Calcium
2. Phosphorous
3. Magnesium
4. Sodium
5. Potassium
6. Iron
7. Zinc
Term
VItamins
Definition
1. Fat-soluble vitamins--stored in adipose tissue
2. Water-soluble vitamins--not stored
3. Not all animals require the same vitamins
4. Vitamins serve as coenzymes (play essential functions in enzyme catalyzed reactions)
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