Question

A researcher wants to determine if a unicellular organism he discovered is an autotroph or a heterotroph. He radioactively labels the carbon in CO2 and C6H12O6, and exposes one culture of his organism to the labeled CO2 and another culture to the labeled C6H12O6. What would happen if his organism is an autotroph?
A. Labeled carbon would be seen in the carbohydrates of organisms exposed to CO2.
B. Labeled carbon would be seen in the carbohydrates of organisms exposed to C6H12O6.
C. Labeled carbon would not be seen in the carbohydrates of either culture.
D. Labeled carbon would be seen in carbohydrates of both cultures.

Answer 1

Answer:

A

Explanation:

Autotrophs utilize the energy from  sunlight to reduce carbon dioxide to carbohydrates (glucose). The energy from the sunlight is used to split water into H+ and O2- and the H+ used in the reduction process. The labeled carbon in the carbon dioxide will, therefore, be incorporated by the autotrophs in the carbohydrates made in photosynthesis.