Which of the following cellular metabolic processes can occur both in the presence or absence of `O_(2)`?

Options

A. Glycolysis
B. Fermentation
C. TCA cycle
D. Electron transport coupled with chemiosmosis

Explanation

To determine which cellular metabolic process can occur both in the presence and absence of oxygen, we need to analyze the options given: glycolysis, fermentation, TCA cycle, and electron transport coupled with chemiosmosis.

### Step-by-Step Solution:

1. **Understanding Metabolic Processes**:
- Metabolic processes are biochemical reactions that occur within cells to convert substrates into products. These processes can be categorized based on their oxygen requirements.

2. **Aerobic vs. Anaerobic Processes**:
- **Aerobic processes** require oxygen to occur (e.g., TCA cycle and electron transport chain).
- **Anaerobic processes** can occur without oxygen (e.g., fermentation).

3. **Analyzing Each Option**:
- **Glycolysis**: This process breaks down glucose into pyruvate and can occur in both the presence and absence of oxygen. In the presence of oxygen, pyruvate enters the TCA cycle; in the absence of oxygen, it can be converted into lactic acid or ethanol through fermentation.
- **Fermentation**: This is an anaerobic process that occurs without oxygen. It cannot occur in the presence of oxygen in the same way.
- **TCA Cycle**: This cycle is strictly aerobic and requires oxygen to function.
- **Electron Transport Chain with Chemiosmosis**: This process also requires oxygen and cannot occur in its absence.

4. **Conclusion**:
- The only process that can occur in both the presence and absence of oxygen is **glycolysis**.

### Final Answer:
The correct answer is **glycolysis**.

---