Question

Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light. Which of the following statements describes a relationship that Engelmann's experiment helped to determine?A. the relationship between wavelength of light and the rate of aerobic respiration. B. the relationship between wavelength of light and the amount of heat released. C. the relationship between wavelength of light and the rate of photosynthesis. D. the relationship between carbon dioxide concentration and the rate of photosynthesis.

Answer 1

Answer:

The correct answer is C and Engelmann conducted this experiment to prove relationship between algae and the rate of photosynthesis.

Explanation: First we must talk about 3 facts:

1) Prism scatters the white light into different wavelengths.

2) Photosynthesis, 6 carbon dioxide and 6 water molecules are consumed and 6 oxygen and 1 sugar molecule is synthesized using light energy.

6CO2 + 6H2O → C6H12O6 + 6O2

3) Aerobic bacteria breaks down sugar while using oxygen and produces water and carbon dioxide in simplified terms.

So with this experimental setup a researcher can understand the rate of the photosynthesis by increased accumulation of aerobic bacteria near algae  in certain wavelengths since they uses oxygen and tend to move close to the oxygen source (see figure). In this experiment there are no ways to measure heat (B), there is no known relation between wavelength of light and aerobic respiration since it can happen even in the dark (A) and finally there are no ways to measure carbon dioxide (D).