Botany Ch. 8

  1. Photoautotrophs
    Organisms that get their energy through photosynthesis; plants, algae, and photosynthetic bacteria.
  2. Chemoautotroph
    An organism, primarily bacteria, that does not rely on photosynthesis but instead gets carbon from CO2 and energy from inorganic chemicals.
  3. Photosynthesis
    The process by which plants use solar energy to make their own food, transforming carbon dioxide and water into sugars that store chemical energy.
  4. Respiration
    Aerobic process of extracting energy from food. Glycolysisreactions take place in thecytosol. Krebs cycle reactions take place in mitochondria.
  5. Photon
    A packet of electromagnetic energy; a photon’s energy depends on its wavelength.
  6. Chlorophyll a
    Blue-green photosyntheticpigment directly involved inlight reactions; absorbs light from the blue-violet and red ranges of the spectrum.
  7. Chlorophyll b
    Yellow-green photosyntheticpigment that acts as anaccessory pigment by transmiting light energy tochlorophyll a molecules. Differs in structure from chlorophyll aby only a few atoms.
  8. Light reactions
    Photosynthetic reactions that occur within thylakoidmembranes of chloroplasts. Inputs are light energy and H2O; outputs are the chemical energy of ATP and NADPH and O2 (as a by-product.)
  9. Photosystem
    One of two light-harvesting units consisting of a reaction center and accessory pigments; absorbs light energy on thestroma side of a thylakoidmembrane.
  10. Electron transport chain
    A series of electron carriers (such as NADH, NADPH, andFADH2) that pass an electron from chlorophyll a through a series of oxidation-reduction reactions during photosynthesisand also during respiration.
  11. Calvin cycle
    Photosynthetic reactions that assemble simple three-carbon sugars, using ATP and NADPH from the light reactions and CO2 from the air; takes place in the stroma of chloroplasts. To make one three-carbon sugar molecule, 3 CO2, 9 ATP, and 6 NADPH are required.
  12. Rubisco
    The abbreviation for the enzymeribulose1,5-bisphosphatecarboxylase/oxygenase, which adds carbon from CO2 to another molecule in carbon fixation. The most abundant protein in chloroplasts. As an oxygenase, rubisco also catalyzes photorespiration, bringing O2 into the Calvin cycle.
  13. C4 pathway
    Addition to the Calvin cycleused by C4 plants common in hot, dry regions; binds CO2 with four-carbon (C4) compounds, which are then used to supply an increased concentration of CO2 to the Calvin cycle. See also C3 plants andcrassulacean acid metabolism.
  14. Photorespiration
    A compromise process common in C3 plants during hot, dry weather when stomata close to prevent dehydration. It uses light and consumes oxygen, but produces no ATP or food because less CO2 is available. C4 photosynthesis and crassulacean acid metabolism are adaptations in other plant species that minimize photorespiration.
  15. Bundle sheath cell
    These cells surround the vascular bundle in flowering plants. In C4 plants, they are large and photosynthetic and are the site of Calvin cycle reactions.
  16. Crassulacean Acid Metabolism (CAM)
    Plants (usually tropical) that use crassulacean acid metabolism (CAM) for carbon fixation at night. Carbon fixation and Calvin cycle reactions occur in the same cells at different times. Typical CAM plants are succulents in the family Crassulaceae, many cacti, and pineapples. These plants close their stomata during the day and open them at night. Compare C3 plants and C4plants.
  17. Wavelength
    Is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves
  18. CO2 Fixation
    Refers to any process through which gaseous carbon dioxide is converted into a solid compound. It mostly refers to the processes found in autotrophs (organisms that produce their own food), usually driven by photosynthesis, whereby carbon dioxide is changed into sugars.
  19. C3 pathway
    The metabolic pathway followed in the light-independent phase of photosynthesis by most plants of temperate regions, in which the first product is the three-carbon compound glycerate 3-phosphate. This is formed when carbon dioxide combines with ribulose bisphosphate in the first reaction of the Calvin cycle. Plants that follow this pathway are referred to as C3 plants.
Card Set
Botany Ch. 8
Chapter 8 Vocab.