Respiration is -

Options

A. Anabolic + Exergonic
B. Catabolic + Exergonic
C. Catabolic + Endergonic
D. Anabolic + Endergonic

Answer

### Step-by-Step Text Solution:

1. **Definition of Respiration**: Respiration is a physiochemical process that involves both physical and chemical components.

2. **Physical Process**: In the physical aspect of respiration, there is an exchange of gases. In plants and animals, the primary gases exchanged are carbon dioxide (CO2) and oxygen (O2).

3. **Chemical Process**: The chemical phase of respiration is crucial for understanding how energy is produced. During this phase, adenosine triphosphate (ATP) is generated, which serves as a form of chemical energy.

4. **Source of Energy**: The primary source of energy in respiration is glucose, a carbohydrate consisting of six carbon atoms (C6H12O6).

5. **Breakdown of Glucose**: When glucose is broken down, it is converted into pyruvate, which is a three-carbon molecule (C3H4O3).

6. **Further Breakdown**: The pyruvate can then be further broken down into acetyl-Coenzyme A (acetyl-CoA), which is a two-carbon compound (C2H3O).

7. **TCA Cycle**: The acetyl-CoA enters the Tricarboxylic Acid (TCA) cycle, which is a series of chemical reactions used by all aerobic organisms to generate energy.

8. **Electron Transport Chain (ETC)**: Following the TCA cycle, the process continues with the Electron Transport Chain, where further energy is extracted.

9. **Oxidative Phosphorylation**: The final stage of respiration is oxidative phosphorylation, which produces the majority of ATP.

10. **Catabolic Process**: Respiration is a catabolic process, meaning it involves the breakdown of larger molecules into smaller ones, releasing energy in the process.

11. **Exergonic Process**: The breakdown of glucose is an exergonic process, indicating that energy is released, primarily in the form of ATP.

12. **Conclusion**: Therefore, respiration can be defined as a catabolic and exergonic process that involves the breakdown of glucose to produce ATP, alongside the exchange of gases.