BIOL 2112 Chapter Notes - Chapter 10: Light-Harvesting Complex, Purple Sulfur Bacteria, Electromagnetic Spectrum
3 May 2018
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Lectures 18-19 Study Guides – Photosynthesis
1) A. What is the difference between a photoautotroph and a heterotroph? Pg. 188, figure
legend 10.2, sentences 1-2; column 2, paragraph 1, sentences 1-2) Photoautotrophs use
light energy to drive synthesis of organic molecules from CO2 and water. Heterotrophs
obtain organic material by the second major mode of nutrition. Unable to make own food,
they live on compounds produced by other organisms. B. List five photoautotrophs whose
oxygen producing capability is critical for life on earth. (Pg. 188, Fig. 10.2) Plants,
multicellular alga, unicellular eukaryotes, cyanobacteria, purple sulfur bacteria. 2) A. In
what type of cell is photosynthesis mainly carried out? (Pg. 189, paragraph 2, sentence 3)
mesophyll cells B. Write the chemical equation for photosynthesis in its simplest form. (Pg.
190) CO2 + H2O
[CH2O] + O2 C. What is the general formula for a carbohydrate that
appears in the equation? (Pg. 190) Synthesis of sugar molecule one carbon at a time
adding up to a glucose molecule. 3) Photosynthesis is a series of oxidation-reduction
reactions. A. What molecule is oxidized and what molecule is reduced in photosynthesis?
(Pg. 191, paragraph 1) Water us oxidized, carbon dioxide is reduced. B. What is the source
of energy needed for this process and why? (Pg. 191, paragraph 1, sentences 7-8) Because
the electrons increase in PE as they move from water to sugar, they require energy from
light. 4) A. In the electromagnetic spectrum, what is the most dangerous type of radiation?
(Pg. 192, Fig. 10.7, lecture notes) Gamma Rays B. How is this radiation minimized on
earth? (Pg. 192, column 2, paragraph 4, sentence 1) Atmosphere selectively allows visible
light to pass while screening out a substantial fraction of other radiation. C. What
segment of the electromagnetic spectrum is the ultimate source of energy for life on
earth? (Pg. 192, column 2, paragraph 2, sentence 4) Visible Light 5) What is the physical
basis for: A) an object that is black in color, absorbs all wavelengths – black, absorbs no
wavelengths – white B) an object that is white in color? (Pg. 193, paragraph 1) 6) A. What
are the energy wavelengths absorbed by most plants? (Pg. 194, Fig. 10.10a) Violet blue and
red light B. How does a plant absorb this broad range of wavelengths? (Pg. 194, paragraph
2, sentences 1-3) Different types of pigments with different absorption spectra in
chloroplasts. C. What are carotenoids and what role do they play in the human eye? (Pg.
194, paragraph 3, sentences 2-4) Hydrocarbons that are various shades of yellow and
orange because they absorb violet and blue-green light. They broaden spectrum of colors
that can drive photosynthesis. Also serve as photo protection. 7) A. What is the difference
between the structures of chlorophyll a and chlorophyll b? (Pg. 194, Fig. 10.11) Chlorophyll
a and chlorophyll b differ in only one of the functional groups bonded to the porphyrin
ring (chlorophyll a – CH3, chlorophyll b – CHO). B. What effect does this difference have on
wavelength absorption? Because of this difference, they absorb at slightly different
wavelengths in red and blue parts of the spectrum. Chlorophyll appears blue green and
chlorophyll b olive green under visible light. (Pg. 192, paragraph 2, sentences 5-6) C.
Where in the chloroplast do you find the light-absorbing porphyrin head of the chlorophyll
molecule? (Pg. 194, Fig. 10.11, lecture notes) In the thylakoid membrane in complexes
called photosystems. 8) The following questions refer to Figure 10.14 and the eight
detailed steps of the light reactions on pages 197-198. A. What occurs when a photon of
light strikes a light-harvesting complex? A photon strikes one of the pigments molecules in
a light harvesting complex of PS II, exciting one of its electrons. As the electron falls back
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Document Summary
Lectures 18-19 study guides photosynthesis: a. 188, figure legend 10. 2, sentences 1-2; column 2, paragraph 1, sentences 1-2) photoautotrophs use light energy to drive synthesis of organic molecules from co2 and water. Heterotrophs obtain organic material by the second major mode of nutrition. Unable to make own food, they live on compounds produced by other organisms. List five photoautotrophs whose oxygen producing capability is critical for life on earth. (pg. 10. 2) plants, multicellular alga, unicellular eukaryotes, cyanobacteria, purple sulfur bacteria. In what type of cell is photosynthesis mainly carried out? (pg. 189, paragraph 2, sentence 3) mesophyll cells b. Write the chemical equation for photosynthesis in its simplest form. (pg: co2 + h2o [ch2o] + o2 c. what is the general formula for a carbohydrate that appears in the equation? (pg. 190) synthesis of sugar molecule one carbon at a time adding up to a glucose molecule. 3) photosynthesis is a series of oxidation-reduction reactions.
