A scientist studying the oxygen concentration in sealed chambers containing cultured plant cells finds that when the chambers are illuminated, the concentration of oxygen increases. However, when the chambers are kept in the dark, the concentration of oxygen decreases. Why does the oxygen concentration decrease when the chamber is kept in the dark?
Plant cell chloroplasts switch their structure and function and become mitochondria.
Plant cell mitochondria consume oxygen by aerobic respiration.
Plant cell chloroplasts run the photosynthetic pathways backward to consume oxygen.
The chambers must not be properly sealed, so that oxygen is leaking out.
The cultures in the chambers must be contaminated with some animal cells, since only animal cells consume oxygen.