Explain how cellular respiration provides energy for the cell by breaking down sugar molecules.

In the process of cellular respiration, the glucose molecules are consumed and a number of products are generated, along with the energy molecules (ATP). The balanced chemical reaction for the process is:

`C_6H_12O_6 + 6O_2 -> 6 CO_2 + 6H_2O + ATP`

In this process, 1 mole of glucose and 6 moles of oxygen are used to produce 6 moles of carbon dioxide, 6 moles of water and ATP (adenosine triphosphate) molecules. The ATP molecules are the energy currency of the cell. 

The process of cellular respiration can take place both aerobically as well as anaerobically. It has been observed that aerobic process is much more efficient, as compared to anaerobic respiration, in terms of ATP molecules generated per molecule of glucose. Aerobic respiration produces about 36 molecules of ATP per molecule of glucose consumed, whereas anaerobic respiration produces only 2 molecules of ATP.

Interestingly, cellular respiration and photosynthesis are complementary processes and each uses the products of the other. 

Hope this helps.