Terms in this set (38)

  • autotroph
    An organism capable of producing complex organic compounds from simple inorganic molecules through the process of photosynthesis (using light energy) or through chemosynthesis (using chemical energy).
  • producer
    Another name for an autotroph.
  • photoautotroph
    An organism that harnesses light energy to drive the synthesis of organic compounds from carbon dioxide.
  • heterotroph
    An organism that obtains organic food molecules by eating other organisms or substances derived from them.
  • consumer
    Another name for a heterotroph.
  • photon
    A particle of electromagnetic radiation with no mass that carries a quantum of energy
  • wavelength
    The distance between crests of waves, such as those of the electromagnetic spectrum.
  • visible light
    Electromagnetic radiation that can be seen with the unaided eye.
  • What is the unit of measurement of wavelengths of light?
    Nanometers
  • _____ wavelengths have the most energy.
    Shorter
  • _____ wavelengths have the least energy.
    Longer
  • When light meets matter, it can be reflected, absorbed, or _____.
    Transmitted
  • Leaves appear green because the pigment _____ reflects and transmits green light.
    chlorophyll
  • action spectrum
    A profile of the relative performance of the different wavelengths in photosynthesis.
  • What autotroph did Engelmann use in his action spectrum experiment in 1883?
    Filamentous algae
  • What gas did Engelmann measure as an indicator of photosynthetic activity?
    Oxygen
  • What organism did Engelmann use as a measure of the amount of the products of photosynthesis?
    Aerobic bacteria
  • What device is used to measure a pigment's ability to absorb various wavelengths?
    Spectrophotometer
  • In a spectrophotometer, if transmittance is low, than absorption is _____.
    high
  • In a spectrophotometer, if transmittance is high, than absorption is _____.
    low
  • Absorption spectrum
    A graph plotting a pigment's light absorption versus wavelength.
  • What two wavelengths of light work best for photosynthesis?
    Violet-blue and red
  • When a pigment absorbs light, it goes from a ground state to a(n) _____ state.
    excited
  • If illuminated with UV light, an isolated solution of chlorophyll will _____, giving off red light and heat.
    fluoresce
  • Chlorophyll is found in the _____ of the mesophyll cells of leaves.
    chloroplasts
  • In addition to light energy, what two other reactants are needed for photosynthesis?
    Carbon dioxide and water
  • chromatography
    The process whereby small amounts of dissolved substances are separated by running a solvent along a material such as absorbent paper.
  • What two organic solvents did we use in the paper chromatography experiment?
    Petroleum ether and acetone
  • Solvent front
    The leading edge of the advancing liquid during chromatography.
  • During chromatography, the pigments move at different rates, depending on their differing _____ in the solvent and their attraction to the filter paper.
    solubilities
  • Which pigment is the most polar?
    Chlorophyll b
  • Chromatography paper (cellulose) is a _____ substance.
    polar
  • The solvent used in chromatography is a _____ substance.
    nonpolar
  • Which pigment will move the slowest during paper chromatography - the most polar or least polar?
    most polar
  • What does Rf stand for in chromatography?
    Retention fraction
  • In Activity 1, what liquid did you boil your leaves that were covered with the filters?
    Ethyl alcohol
  • In Activities 1 and 2, what chemical did we test for to determine the presence of photosynthesis?
    Starch
  • In Activity 1, which color filter allowed the greatest photosynthetic activity?
    Blue