Hi there!
This process is known as cellular respiration. It is essential for all living to survive because it allows aerobic organisms to convert food into energy - without cellular respiration, we would not be able to produce energy, making it impossible to perform bodily functions that are important for life.
The word equation for cellular respiration is:
Glucose (energy) + Oxygen + Water ⇒ Carbon Dioxide + Water
The balanced chemical equation for cellular respiration is: C₆H₁₂O₆+6O₂+6H₂O⇒6CO₂+12H₂O
Hope this helps!