The correct answer is two major stages. The first stage is known as the light reactions where solar energy is converted to chemical energy. The second stage is the Calvin cycle that synthesizes sugar.

Glucose is the six carbon sugar that is the main product of photosynthesis. Water and carbon dioxide are the reactants in photosynthesis. Lipids are fat molecules that store energy in cells.

In photosynthesis, water, carbon dioxide, and energy in the form of sunlight are inputs, and the outputs are glucose and oxygen. A nonspontaneous reaction is one that will not proceed without the net input of energy (in this case, sunlight).

CAM plants open their stomata only at night, when temperatures are lower and water loss is less severe. This prevents gas exchange during the day thus making them less efficient at photosynthesis, but the water conservation makes it a worthwhile trade off. The processes of glycolysis, oxidative phosphorylation, the Calvin cycle and the Krebs cycle occur in all plants.

Plants are considered photoautotrophs, meaning that they can use the electromagnetic energy from sunlight to generate organic chemical energy. The process for this conversion is photosynthesis, which takes place in the chloroplasts of the plant cells. Sunlight excites electrons, which donate energy to form NADH and ATP. These compounds enter the Calvin cycle, which converts carbon dioxide to glyceraldehyde-3-phosphate, a sugar that can easily be converted to glucose and used for energy.

The sugars produced from photosynthesis then undergo oxidation via cellular respiration in order to actually produce ATP. Remember that plant cells contain both chloroplasts (to make sugars) and mitochondria (to make ATP).

Oxygen is the final electron acceptor in aerobic respiration. It becomes water upon being reduced by the accepted electrons, which explains why water is one of the products of respiration. Without the presence of oxygen, electrons would remain trapped and bound in the final step of the electron transport chain, preventing further reaction.

NADH and FADH₂ are necessary to donate electrons to the electron transport chain.

Aerobic cellular respiration is the process of breaking down glucose  to form intermittent electron electron carriers, which eventually donate their electrons to the final electron acceptor, oxygen, at the end of the electron transport chain. This process produces usable energy in the form of ATP, as well as waste produced of carbon dioxide and water.

One way to divide prokaryotes is into aerobes and anaerobes. Aerobes are organisms that can survive and grow in the presence of oxygen while anaerobes did not require oxygen for survival and growth. All aerobes can produce ATP with or without oxygen (though they may need oxygen for survival. However some anaerobes are harmed by the presence of oxygen (obligate anaerobes). These anaerobes can produce ATP through glycolysis or anaerobic respiration, where another molecule besides oxygen is used as the final electron acceptor for the electron transport chain.

If no oxygen is available, anaerobic respiration will occur. This can either be lactic acid fermentation, or alcoholic fermentation. In alcoholic or lactic acid fermentation, the pyruvate are decarboxylated and ultimately used to produce either ethanol or lactic acid, and regenerate NAD+ which will be reused for another cycle of glycolysis (2 ATP are produced for each round of glycolysis).

If no oxygen is available, anaerobic respiration will occur. This can either be lactic acid fermentation, or alcoholic fermentation. In alcoholic or lactic acid fermentation, the pyruvate are decarboxylated and ultimately used to produce either ethanol or lactic acid, and regenerate NAD+ which will be reused for another cycle of glycolysis (2 ATP are produced for each round of glycolysis).