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Plants:
Domain & Kingdom
General Charecteristics
- - Domain: Eukarya (multicellular)
- - Kingdom: Plantae
- - Autotrophs: produce own food/nutrients
- - Cell walls made of cellulose
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Angiosperms
Flowering plants
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Root System
- - Located underground
- - anchor and support
- -Absorbs water and minerals
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Shoot System
- - Only in angiosperms (flowering plants)
- - Consists of stem and leaves
- - Stems role: transports water and minerals from the roots to the leaves. Also transports the products of photosynthesis.
- - Leaves role: Photosynthesis
- - Water, Carbon Dioxide, Sunlight
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Stem
- - Main axis of the plant (angiosperms)
- - Supports the leaves
- - Contains vascular tissues
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Leaf
- - Major part of the plant that carries out photosynthesis
- - Waxy cuticle that reduces gas exchange
- - Contain Guard Cells (epidermal cells with chloraplasts) and Stomata (small pore in leaf epidermis)
- - Usually Broad and flat
- - Blade: Wide portion of leaf
- - Petiole: Stalk that attaches blade to stem
- - Axillary Bud: Originates from leaf axil
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Deciduous Plants
Plants that lose their leaves every year.
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Meristematic Tissue
- Allows a plant to grow its entire life by retaining cells that have the ability to divide and produce more tissues
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Apical Meristem
- - Meristematic tissue that is present in the root tip and shoot tip
- - Produces 3 types of primary meristem which develop into 3 types of specialized tissue
- - Epidermal Tissue
- - Ground Tissue
- - Vascular Tissue
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Epidermal Tissue
- - Forms the outer protective covering of a plant
- - Modified in the roots, stems, and leaves
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Ground Tissue
- - Forms the bulk of a plant and contains 3 types of specialized cells
- - Parenchyma: deeper within plant tissue
- - Collenchyma: Under the cuticle
- - Sclerenchyma: Lingin
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Difference between Parenchyma, Collenchyma, and Sclerenchyma cells
Thickness of cell membrane.
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Vascular Tissue
- - Provides internal system of conduction
- - 2 types
- - Xylem, Phloem
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Xylem
- - Vascular tissue that transports water and minerals from the roots to the leaves.
- - Complex Tissue
- - 2 types of conducting cells
- - Vessel elements: Shorter and wider with perforated plates in their end wall
- - Tracheids: Long with tapered ends and are less efficient transporters, but allow water to move across end or side walls
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Phloem
- - Vascular tissue that transports sugars and other organic compounds throughout the plant.
- - Sieve-Tube members:
- - Arranged to form a continuous Sieve-Tube
- - Contain cytoplasm, but no nuclei
- - Have nucleated companion cell that keeps both cells alive
- - Connected by plasmodesmata
- - Compound Tissue
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Complex Tissue
Contains more than one type of cell
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Cotyledons
Stores the nutrient molecules that the embryo uses
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Monocot
- - One cotyledon
- - Endosperm is the food-storage tissue
- - Xylem and phloem in a ring
- - Vascular bundles are scattered
- - Leaf veins form parallel pattern
- - Flower parts in 3 and multiples of 3
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Eudicots
- - Two or more cotyledons
- - Cotyledons supply nutrients to embryo and seedling
- - Phloem between arms of xylem
- - Vascular bundles in distinct ring
- - Leaf veins form a net pattern
- - Flower parts in 4 and 5 and their multiples
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Transpiration
When water reaches the leaves and then ecaporates
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Opening and Closing of Stomata
- *Stoma are bordered by guard cells*
- - Influenced by environmental conditions
- - Open stomata: guard cells fill with water, gas exchange occurs
- - Closed stomata: guard cells are empty
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Plants evolved from:
- - Freshwater green algae 450 million years ago
- - Common Traits:
- - Chlorophyll A and B
- - Store excess carbs as starch
- - Have cellulose in cell wall
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5 Major Evolutionary Events for Life on Land
- 1. Embryo Production
- 2. Vascular Tissue
- 3. Megaphylls
- 4. Seeds
- 5. Flowers
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Alternation of Generations
- - Two multicellular individuals (sporophyte and gametophyte) alternate, each producing the other
- - Plants differ as to which generation is dominant
- - Dominant Generation: Most conspicuous and carries out most of the photosynthesis
- - Nonvascular plants: Gametophyte
- - Vascular plants: Sporophyte
- - A shift to sporophyte dominance is an adaptation for life on land
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Sporophyte
- - 2n (Diploid)
- - Produces spores by meiosis
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Gametophyte
- - n (Haploid)
- - Produces gametes by mitosis
- - Sperm and egg fuse = diploid zygote
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Changes That Occurred with Adaptation to Terrestrial Life
- - Gametophyte = Smaller
- - Sporophyte = Larger
- - Mosses and ferns: spores disperse gametophyte
- - Gymnosperms and angiosperms: seeds disperse sporophyte
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Nonvascular Plants
- - Lack vascular tissue, true roots, stems, leaves
- - Dominant Generation = Gametophyte
- - Flagellated sperm swim to egg
- - 3 Divisions- Phylum: Bryophtye
- - Horns, Liverworts (flat, lobed thallus OR leafy), Mosses
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Mosses
- - Live in a variety of enviornments
- - Most can reproduce asexually by fragmentation
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Adaptations and Uses of Nonvascular Plants
- - Can live on bare rock, fences, cracks in sidewalks, stone walls
- - Help convert rocks to soil
- - Peat moss forms in bogs as it accumulates
- - Used as fuel, holds water
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Vascular Plants
- - Have vascular tissue
- - Have true roots, stems, and leaves
- - Dominant Generation: Sporophyte
- - Some do not produce seeds
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Seedless Vascular Plants
- - Two groups: Lycophytes & ferns and their allies
- - Produce windblown spores
- - Flagellated sperm released by antheridia
- - Swim in a film of external water to archegonia
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Ferns
- - Phylum: Polypodiophyta
- - Largest group of plant other than flowering plants
- - Great diversity in form and habitat
- - Warm, moist, tropical regions
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Life Cycle of Fern
Dominant sporophyte produces windblown spores, when spore germinates the gametophyte (water dependent) develops.
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Lycophytes
- - aka Club Mosses
- - Among 1st land plants to have vascular tissue
- - Common in moist woodlands in temperate climates (ground pines)
- - Also in tropics and subtropics
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Seed Vascular Plants
- - Most plentiful in biosphere today
- - Seeds contain sporophyte embryo and stored food which allows an embryo to survive long periods of dormacy
- - Seeds germinate under favorable conditions
- - Heterosporous: two types of spores and produce male (produced by pollen grain) and female (develops in ovule) gametophytes
- -Gymnosperms and Angiosperms
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Gymnosperm
- - "Gymno" = Greek for naked
- - Most are cone-bearing
- - Ovules located on surface of cone scales
- - Ovules not completely enclosed by diploid tissue
- - Later become seeds
- - 4 groups: conifers, cycads, ginkgoes, gnetophytes
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Pollination
Deposition of pollen on a female gametophyte.
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Pollen Tube
Path followed by sperm to reach ovule
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Conifers
- - Phylum: Pinophyta
- - Evergreens; best known gymnosperms
- - Oldest and largest trees on Earth
- - Adapted to cold, dry weather
- - Dominant sporophyte produces 2 kinds of cones:
- - Pollen Cones (male) & seed cones (female)
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Ginkgoes
- - Phylum: Ginkgophyta
- - Maidenhair Tree = only surviving species
- - Females produce fleshy seeds that give off a foul odor
- - Resistant to pollination
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Angiosperms
- - Phylum: Magnoilophyta
- - Flowering plants
- - Very large and successful group
- - 240,000 known species
- - Live in all types of habitats
- - Large size range (microscopic-100 meters)
- - Seeds develop from an ovule within an ovary, which becomes the fruit
- - Covered seeds
- - Co-evolved with insects
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Pollinator
Animal that carries pollen to another flower.
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Receptacle
- - Tip of stalk that bears flower
- - Also bears sepals, petals, stamens, and carpels
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Sepals (caylx)
- Modified leaves that protect bud
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Petals (corolla)
- Modified leaves, may be colorful to attract pollinators
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Stamen
- - Male reproductive structure
- - Anther: pollen production
- - Filament: stalk
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Carpel (pistil)
- - Female reproductive structures
- - Stigma: pollen receptor
- - Style: elevates stigma
- - Ovary: ovule production and containment
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Life Cycle of Flowering Plants
- - Dependent on flower which produces both pollen and seeds
- - Pollination can be wind or pollinator
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The Fruit
- Final product of a flower, aids in the dispersal of seeds
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Microbiology
Study of microbes.
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Microbes
- - aka Microorganisms
- - Bacteria, archea, protists, fungi, viruses, viriods, prions
- - Most require a microscope to be seen
- - Are everywhere
- - Many cause human disease
- - Others provide important benefits
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Discovery of Microbial World
- - Late 1600s:
- - "Animalcules": microscopic life forms in water
- - Spontaneous generation
- - Late 1800s:
- - Louis Pasteur
- - Used microbes to discredit the theory of spontaneous generation in 1859
- - Virus caused rabies
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Origin of Microbial Life
Single common ancestor (3.5-4 billion years ago).
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Bacteria
- - Most common prokaryote on Earth
- - 9,000 species identified, estimated to be 10s of millions unnamed species
- - Found everywhere
- - 3 shapes:
- - Rod (bacilli), Spherical (cocci), Curved (spirillium)
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Bacteria Structre
- - Capsule (not present in all bacteria)
- - Cell Wall: helps determine different types of bacteria
- - Plasma Membrane
- - Plasma
- - Single circular chromosome (DNA) located in nuceloid (RNA) region
- - Plasmids: accessory rings of DNA that carry genes
- - Ribosomes
- - Storage granules
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Classification of Bacteria
Based on size and structure
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Gram Stain Method
- - Used to classify bacteria based on differences in cell wall
- - Most widely used
- - Result (positive or negative) is used to select antibiotics
- - Gram Positive: Thick cell wall (thick layer of peptidoglycan)
- - Gram Negative: Thin or lacking cell wall (thin layer/lacking layer of peptidoglycan)
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Bacterial Endospore
- - allows for survival in harsh conditions
- - Thick-walled, dehydrated structure
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Binary Fission
- - Asexual reproduction in bacteria
- - Replication & division = 2 new daughter cells
- - Daughter cells are clones (exact copy)
- - Duration: 20 min - A day or more
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Conjugation
Donor cell passes DNA to recipient cell via sex pillus.
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Transformation
Bacterium takes up DNA from environment released by dead bacteria.
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Transduction
Viruses carry bacterial DNA from cell to cell.
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Hetertrophic
- - Require an outside source of organic compound
- - Aerobic: use oxygen
- - Anaerobic: use sulfate or nitrate
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Chemoautotrophs
- - Reduce carbon dioxide to organic compound
- - Uses electrons
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Photosynthetic
- - Use solar energy to produce food
- - ex: Cynobacteria
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Cynobacteria
- - Have chlorophyll and other pigments
- - 3.8 billion years ago
- - Most oxygen of Earths atmosphere
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E. Coli
- - Bacterial disease
- - Many non-harmful strains live in our large intestines
- - E. Coli O157:H7 generates toxins that damage intestines lining
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Streptococcus Infections
- - Cause more disease than any other bacteria
- - Streptococcus pneumoniae: pneumonia, meningitis, middle ear infections
- - Streptococcus mutans: contributes to dental caries
- - Streptococcus pyogens: causes the most diseases (ex: strep throat)
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Staphylococcus aureus
- - about 20% of people are carriers
- - Mostly skin infections
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MRSA
- - Staph strain resistant to methicillin
- - Can be deadly
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Tuberculosis (TB)
- - A leading cause of death worldwide due to infectious disease
- - Very slow growing bacteria
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Antibiotics
- - Inhibit reproduction of bacteria by interfering with unique metabolic pathways
- - Work in 2 ways:
- - inhibit protein synthesis
- - inhibit cell wall biosynthesis
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Viruses (obligate parasites)
- - Acellular structures
- - Require a living cell to reproduce
- - Use host cells replication machinery
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Prions
- - Simpler than viruses
- - Proteins molecules that cause other proteins to become prions
- - Neurodegenerative diseases
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Viral Infections
- - Once in body, can reproduce and the person will have it in their body for the rest of their life
- - Even if asymptomatic, they are still infected
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Viral Size and Structure
- - Smaller than bacteria
- - Shapes: helix, sphere, polyhedron, and more complex forms
- - 2 main components:
- - Capsid (outer portion comprised of protein)
- - May be surrounding a lipid envelope
- - May have spikes for attachment
- - Nucleic Acid Core (RNA and DNA)
- - Both may be single or double stranded
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Viral Reproduction
- - Infect almost every type of organism on Earth
- - Each virus is specific to a certain host
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