Question

question 16
this microbe is photosynthetic, but in the absence of light it can use organic compounds as an energy source. its
carbon source is an organic compound. the appropriate classification for this organism would be _.
a lithotroph
b photoautotroph
c photoheterotroph
d chemoautotroph

Explanation:

• Lithotroph: Obtains energy from inorganic substances, which is not the case here as the microbe uses organic compounds in the absence of light.
• Photoautotroph: Uses light as energy and \(CO_2\) as a carbon source. But this microbe uses organic carbon, so this is incorrect.
• Photoheterotroph: Uses light for energy (photosynthetic) and organic compounds as a carbon source. This matches the description.
• Chemoautotroph: Obtains energy from chemical reactions and \(CO_2\) as a carbon source. Not relevant to the given description.

Answer:

C. photoheterotroph