## Explanation

Cellular respiration is considered a **spontaneous reaction** because the Gibbs Free Energy ($\Delta G$) for the process is **negative**. This indicates that the reaction occurs naturally without the need for external energy input.

### Gibbs Free Energy

The spontaneity of a reaction is determined by the Gibbs Free Energy change, given by the formula:

$\Delta G = \Delta H - T\Delta S$Where:

- $\Delta G$ is the change in Gibbs Free Energy
- $\Delta H$ is the change in enthalpy
- $T$ is the temperature in Kelvin
- $\Delta S$ is the change in entropy

For cellular respiration, this can be expressed as:

$\Delta G_{\text{respiration}} = -nFE_{\text{cell}}$Where:

- $n$ is the number of moles of electrons transferred
- $F$ is the Faraday constant
- $E_{\text{cell}}$ is the cell potential

### Breakdown of Cellular Respiration

During cellular respiration, glucose ($C_6H_{12}O_6$) reacts with oxygen ($O_2$) to produce carbon dioxide ($CO_2$), water ($H_2O$), and energy. The overall reaction can be summarized as:

$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$### Key Points

- The breakdown of glucose in the presence of oxygen releases a substantial amount of energy, leading to a large negative $\Delta G$.
- A negative $\Delta G$ value confirms that cellular respiration is thermodynamically favorable and spontaneous.
**High entropy ($\Delta S$)**: The reaction leads to an increase in disorder (more molecules of $CO_2$ and $H_2O$ as compared to glucose and $O_2$), contributing to the negative $\Delta G$.

### Conclusion

**Cellular respiration is a spontaneous reaction** due to its large negative Gibbs Free Energy change, which ensures the process occurs naturally and efficiently, providing the necessary energy for various biological functions.