Chapter 10

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Unformatted text preview: . As s hown in the image below, mos t of the bac teria were attrac ted to the regions of the alga illuminated by red or v iolet­blue light. This dis tribution of bac teria s hows that red and v iolet­blue wav elengths are mos t effec tiv e in driv ing photos y nthes is . By meas uring ox y gen produc tion with aerotac tic bac teria, Engelmann des c ribed an ac tion s pec trum for photos y nthes is . The ac tion s pec trum (indic ated by the blac k line plot in the image abov e) s hows the relativ e effec tiv enes s of eac h c olor of light in driv ing photos y nthes is . se ste r ingbiology.c om/myc t/a ssignme ntPr intVie w? a ssignme ntI D= 2242937 8/41 13- 10- 13 Cha pte r 10 What assum ptions did Engelm ann m ake in order to conclude that red and violet­blue light were m ore effective than green light in driving photosynthesis? Select the two that apply. Hin t 1. T he relationship between the number of bacteria and the amount of oxygen produced The amount of ox y gen produc ed in photos y nthes is inc reas es with the amount of time that the s ample (the alga in Engelmann’s ex periment) is illuminated. The image below s hows the number of aerotac tic (ox y gen­s eek ing) bac teria that c lus ter near an illuminated algal c ell as time pas s es . Note that the longer the algal c ell is illuminated, the more ox y gen it produc es , and the more bac teria are attrac ted to it. Thus , Engelmann deduc ed that the number of bac teria at any loc ation on the mic ros c ope s lide is related to the amount of ox y gen at that loc ation. Hin t 2. Would the distribution of chloroplasts in each algal cell affect the outcome of Engelmann’s experiment? Cladophora is a filamentous green alga. Eac h c ell in the filament c ontains many s mall c hloroplas ts that are ty pic ally dis tributed uniformly around the periphery of the c y toplas m. Cons ider two different Cladophora c ells , eac h with the s ame number of c hloroplas ts . One c ell’s c hloroplas ts are uniformly dis tributed throughout the c ell (top), and the other c ell’s c hloroplas...
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This document was uploaded on 02/17/2014 for the course BIOCHEMIST 2550 at Ohio State.

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