How mitochondria and chloroplasts are opposites in function?

Answer 1

There is no definite difference in function, however the necessary catalysts are quite different. Chloroplasts require sunlight to start, whereas mitochondrion do not require light.

REVISION:

I disagree with the previous answer - the function of a mitochondria and a chloroplast are fundamentally different, indeed nearly opposite in many respects. Chloroplasts are the site of photosynthesis whereby light energy and carbon dioxide are utilized to form sugars. Mitochondria are the site of much of cellular respiration (parts of cellular respiration also occur in the cytoplasm) where oxygen and sugars are broken down to generate energy and carbon dioxide. Plants utilize their chloroplasts to generate sugars wherein the energy of the sun can be stored and later used by their mitochondria and cellular respiration to generate energy.

Answer 2

Mitochondria are responsible for cellular respiration, which involves the breakdown of organic molecules to generate energy in the form of ATP. Chloroplasts, on the other hand, are involved in photosynthesis, where they convert light energy into chemical energy in the form of glucose. Mitochondria produce ATP while consuming oxygen, while chloroplasts produce glucose while consuming carbon dioxide.