Question

Experimental Inquiry: Which Wavelengths of Light Drive Photosynthesis? WORD O ( 10 of 11 T diamento 500 600 Wavelength of light (nm) Add om so by man s on Education, the By measuring oxygen production with aerotactic bacteria Engelmann described an action spectrum for photosynthesis. The action spectrum (indicated by the black line plot in the image above) shows the relative effectiveness of each color of light in diving photosynthesis What assumptions did Engelmann make in order to conclude that red and violet-blue light were more effective than green light in driving photosynthesis? Select the two that apply. The distribution of chloroplasts within each algal cell was approximately the The number of bacteria clustered at each wavelength(color) was approximately proportional to the amount of oxygen being produced by that portion of the The alga absorbed the same number of photons at each wavelength (color)

Answer 1

Englemann passed the light of different wavelengths to the different part of alga by using a microscope that had prism. He kept the aerobic bacteria within the alga. He noticed that the accumulation of aerobic bacteria to that portion of alga which got blue and red light was higher than any other region of algal body. This was because that portion of alga which got blue and red light showed maximum rate of photosynthesis, hence liberated maximum oxygen. The rate of photosynthesis in blue and red light was high because the chlorophyll molecule absorb the light of specific wavelengths (that correspond to blue and red light) . Light of all wavelengths is not absorbed by chlorophyll. Since the bacteria was aerobic they accumulated within that region. The distribution of chloroplast was same for every segment of alga.

So the option A and B is correct. Option C is incorrect.