Please enable JavaScript.

Coggle requires JavaScript to display documents.

Exam 2 - Coggle Diagram

- - - - layers of photosynthetic bacteria/cyanobacteria
        
        cyanobacteria
        
        likely the oldest known fossilized organism
        
        Chemical clues, 2-methylhopane almost exclusive in cyanobacteria cell walls
      - Secrete mucilage sticking together in thin mats on rock surface
    - - Only at tips find organisms that require oxygen in high concentrations
    - - Iron was plentiful and very little free oxygen
      - Iron depleted and then oxygen began to build up in atmosphere
    - - Went from iron rich environment to oxygen rich environment
  - - - Thykaloid reactions
        
        light reactions
      - Stromal reactions
        
        dark reactions
        
        Calvin-Benson- Bassham Cycle
    - - likely started as sunscreen
      - early on there was no ozone layer
      - Cyanobacteria with scytonemin in sheath, pigment that protects them for UV radiation
      - Chlorophyll similar to hemoglobin and likely common ancestor
    - - Molecules that absorb particular wavelengths of light energy and reflect others
      - plants are whatever color based on whether they reflect, absorb, or transmit green light
        
        Absorbed light energy
        
        electrons excite
        
        electron bumps to next orbital
        
        electron will be passed to next electron or fall back to original orbital
        
        if it falls back it will release energy in the form of heat and fluorescence
        
        Absorbance spectrum
        
        absorbed energy depends on the pigment
        
        visible spectrum used
      - Chlorophyll
        
        Chlorophyll a
        
        most abundant pigment in plants
        
        peak absorbance
        
        430 nm and 660 nm
        
        Chlorophyll b
        
        second most abundant
        
        peak absorbance
        
        450 nm and 650 nm
      - must have accessory pigments
        
        accessory pigments
        
        Carotenoids
        
        Beta carotene
        
        Help broaden absorption spectrum
        
        Also act as sunscreen
        
        Visible during the fall
      - Resonance energy
        
        absorption and excitation occurs in photosystems
        
        Absorbed energy is moved around via resonance energy
        
        funneled to reaction center
        
        special chlorophyll a
  - - - consists of
        
        Antennal complex
        
        Accessory pigments
        
        Chlorophyll pigments
        
        Reaction center
      - embedded in the thylakoid
    - - PSI
        
        P700
        
        absorb longer wavelengths
        
        Chl a>>Chl b
      - PSII
        
        P680
        
        absorb shorter wavelengths
        
        Chl b >> Chl a
        
        Hydrolosis
    - - some energy used to make it stable
      - energy released in a stepwise controlled manner
    - - electrons passed from PSII to PSI
        
        Excited PSII electron grabbed by pheophytin
        
        Passed to plastoquinone
        
        Passed to cytochromeb6f complex
        
        Passed to plastocyanin
        
        Passed to PSI
      - Electron from PSI to NADP+
  - - - Flow of electrons does not directly create ATP
      - Electron flow coupled with flow of protons
      - Electron energy drops when flow through cytochrome complex
      - Electrons return to chlorophyll
      - Protons trapped in special internal chamber, thylakoids
      - summary
        
        PSI
        
        Plastoquinone
        
        Cytochrome b6f
        
        Plastocyanin
    - - e- from PSII to NADPH
        
        NADPH
        
        more powerful than ATP
        
        sulfur bacteria beginnings
        
        One photosystem
        
        Pull electrons off hydrogen sulfide
        
        Chlorophyll = bacteriochlorophyll
        
        H2S
        
        structure similar to H2O
        
        Sulfur lower redox potential than oxygen
      - NAD+
        
        great oxidizer
        
        final electron acceptor
    - - light energy to split water
      - Oxygen evolving complex of PSII
      - Oxygen and protons released
      - Oxygen diffuses out of stomata
      - Protons left behind
    - - Plastoquinone & Cytochrome b6f work in concert to bring protons from stroma to lumen
      - lake of protons
      - cyclic and noncyclic
  - - - Ribulose 1,5-bisphosphate carboxylase oxygenase
      - Fixes CO2 into organic carbon
      - Up to 50% total soluble protein in plant leaf or microbe
    - - Reduction
        
        Energy from ATP stored into C3 molecule
        
        Energetic electrons reduce C3 molecule
        
        Ends in a pool of G3P (C3)
      - Regeneration
        
        Carbon shuffling
        
        Get the RuBP back (C5)
        
        Takes more ATP
      - Fixation
        
        CO2 bound to RuBP (C5)
        
        Immediately breaks into 2 C3
    - - RuBisCO binds to CO2 and O2
      - if low CO2 it binds to O2
      - Disadvantages
        
        Not as efficient
        
        Produces toxic by-product
      - Advantages (sometimes)
        
        High light tolerance
        
        Reduce photo-inhibition
        
        Provides metabolites for other processes, including stress protection proteins
        
        Alpine environments
        
        Drought prone environments
        
        High salinity environments
    - - production of glucose
      - occurs in the chloroplasts, amyloplasts, and cytosol
- - - - Greek, haploos + einai = single being
    - - haplodiplontic
        
        Greek, haploos + diploos + einai = single double being
    - - also known as interpolation theory
        
        Predictions
        
        Heteromorphic generations
        
        a short lived and simple sporophyte
        
        a relatively complex and persistent gametophyte
  - - - Dominant leafy gametophyte
        
        dominant life stage
        
        Antheridiophore
        
        male
        
        antheridia
        
        contain sperm
        
        Archegoniophore
        
        female
        
        archegonia
        
        contain eggs
      - Temporary diploid sporophyte
        
        sporophyte
        
        Small, temporary structure
        
        Parasitic on gametophyte
        
        Meiosis occurs within sporangium
        
        Sporocytes (2n)
        
        Spores (1n)
    - - Dominant leafy gametophyte
        
        Dominant life stage
        
        Antheridial head
        
        Male
        
        antheridia
        
        contain sperm
        
        archegonial head
        
        female
        
        archegonia
        
        contain eggs
      - Temporary diploid sporophyte
        
        sporophyte
        
        Small, temporary structure
        
        Parasitic on gametophyte
        
        Meiosis occurs within sporangium
  - - - Selaginella example
      - Heterosporous
      - Retained within spore walls
      - Sperm must still swim to egg
      - gametophyte
        
        Both male and female develop within spore wall
        
        small
      - sporophyte
        
        Heterosporous
        
        Reduction in megasporocytes to 1 per megasporangium
        
        Micro = male
        
        Mega = female
    - - Polypod fern example
      - Independent gametophyte
      - Independent sporophyte
      - Gametophyte
        
        Microgametophytes
        
        Male
        
        Antheridium
        
        Sperm
        
        Megagametophytes
        
        Female
        
        Archegonium
        
        Egg
      - Sporophyte
        
        sori
        
        large persistant diploid
  - - - Pine example
      - Microgametophyte no longer restricted to water
      - Megagametophyte protected by integuments
      - sporophyte
        
        Large dominant diploid stage
        
        Gametophyte reduced to microscopic structures
      - gametophyte
        
        Microgametophyte
        
        pollen
        
        Megagametophyte
        
        Becomes nutritive tissue
        
        Protected by integuments
        
        Within an ovule
    - - Lily example
      - Sporophyte dominant
      - Gametophytes microscopic
      - sporophyte
        
        The flowering plants are very diverse
        
        Annual to perennial
        
        Indeterminate growth
      - microgametophyte
        
        Multicellular haploid stage
        
        pollen grain
        
        immatute
        
        mature germinating
      - megagametophyte
        
        Multicellular haploid individual
        
        Egg one of the cells (nuclei)
- - - - current oxygen level
        
        20.9% O2
        
        535 times more O2 than CO2
      - oxygen level when land plants began to appear
        
        8-15 times more O2 than CO2
        
        4% O2
        
        weak ozone
        
        tissues were thin
    - - 470 mya
      - major changes in morphology and reproduction
      - multicellular sporophyte retain the zygote & embryo within the female gametophyte
    - - Charophycean green algae
      - Streptophyta
        
        Group includes Embryophyta and charophytes
    - - earliest spore and tissue fragment evidence 470 mya
      - trilete mark
      - cryptospores
        
        likely liverwort
        
        Liverwort macrofossils
        
        390 mya
        
        Dichotomously branched
    - - Cooksonia sporophytes
        
        425 mya
      - gametophyte complex
        
        Stomata
        
        Conducting elements
        
        Similar to extant liverworts
    - - Specialized conducting cells
      - spores 443 mya
      - Tracheid fossils 415 mya
  - - - Alternation of generations
      - Gametophyte dominant in early land plants
      - Sporophyte evolves dominance
    - - All land plant sporophytes but liverworts
      - Often aerial surfaces covered with cuticle
    - - Downward growing rhizomes
      - Positive gravitropism
      - Negative phototropism
      - Evolved a root cap
      - Early roots branched at tip
    - - Gametophyte completely dependent on sporophyte
      - Egg protected by special layers of tissue
      - Seed ferns
      - gymnsperm
        
        naked seed
      - angiosperm
        
        hidden seed
    - - Stem specialization
      - Attraction
      - Dispersal
      - Coevolution
- - - - 400 mya stomata scattered across sporangia
      - Similarities link to similar functions in extant angiosperms
    - - Likely the origin of stomata
      - Aid in desiccation of sporophyte
      - Stomata near sporophyte sporangia
      - Aid in spore dispersal
      - Likely not regulated
      - May have permitted some CO2 to enter
    - - Support early role different from today
      - Location on non-photosynthetic sporophyte tissue in early lineages
      - Extant early lineages have stomata that only open
    - - Pseudostomata continuous with epidermis or hypodermis, no space
      - Space filled with fluid with space made by cells pulling apart
      - Stomatal canal, small air space
    - - Monocot (grass)
        
        Dumbbell shape
        
        Same direction as epidermal cells
      - Eudicot
        
        Kidney-shaped
        
        Random orientation
  - - - Active metabolic processes
        
        Increase turgor pressure
        
        Moves ions, water follows by osmosis
      - Cytoskeleton microfibrils radially oriented
    - - Provides ATP for potassium pump
      - Protons are pumped out
      - Potassium moved in
      - Ancestral condition filled with chloroplasts
      - Closure at night or under water stress
    - - Amount of water loss to carbon gain
      - Close pore during water stress
      - Derived character
      - Reduce probability of cavitation
      - ABA responsive in seed plants