Final answer:
The major processes are photosynthesis in chloroplasts and cellular respiration in mitochondria, both of which are contained in double-membraned organelles and use a cytochrome complex.
Step-by-step explanation:
The major process that occurs in the organism (2) referenced is likely photosynthesis, which takes place in the chloroplasts of plant and plant-like cells. Chloroplasts have a double membrane and contain their own DNA and ribosomes. In the light-dependent reactions of photosynthesis, the energy from sunlight is absorbed by chlorophyll in the chloroplasts, producing oxygen from water. The light-independent reactions, also known as the Calvin cycle, then use carbon dioxide to produce glucose. These processes are facilitated by the cytochrome complex involved in the electron transport chain.
In the case of the mitochondrion, it deals with cellular respiration, which is the process of making ATP using the chemical energy found in glucose and other nutrients. Mitochondria are also double-membraned organelles that use a version of the cytochrome complex for their processes. Cellular respiration occurs in several steps, including glycolysis, the citric acid cycle, and oxidative phosphorylation.