Which technique has helped in investigation of Calvin cycle ?
(a) Radioactive isotope technique
(b) Biotechnology technique
(c) Photometric technique
(d) Flashlight experimental technique

Options

A. Radioactive isotope technique
B. Biotechnology techinque
C. Photometric technique
D. Flash light experimental technique

Answer

To solve the question "Which technique has helped in the investigation of the Calvin cycle?" we need to analyze the options provided and understand the significance of each technique in relation to the Calvin cycle.

### Step-by-Step Solution:

1. **Understanding the Calvin Cycle**:
The Calvin cycle is a crucial part of photosynthesis where carbon dioxide is fixed into organic molecules. It involves a series of biochemical reactions that convert carbon dioxide and ribulose-1,5-bisphosphate (RuBP) into glucose and other carbohydrates.

2. **Analyzing the Options**:
- **(a) Radioactive isotope technique**: This technique involves using isotopes, such as Carbon-14, to trace the path of carbon in photosynthesis. Melvin Calvin used this technique to investigate the Calvin cycle.
- **(b) Biotechnology technique**: While biotechnology encompasses various methods for studying biological processes, it is not specifically linked to the investigation of the Calvin cycle.
- **(c) Photometric technique**: This technique measures the intensity of light and is not directly related to the biochemical pathways of the Calvin cycle.
- **(d) Flashlight experimental technique**: This option seems vague and does not correspond to any established scientific method used in the study of the Calvin cycle.

3. **Identifying the Correct Answer**:
The radioactive isotope technique, specifically the use of Carbon-14, was instrumental in tracing the steps of the Calvin cycle and identifying key products like phosphoglyceraldehyde (PGA). This led to the understanding of carbon fixation in plants.

4. **Conclusion**:
Based on the analysis, the correct answer to the question is **(a) Radioactive isotope technique**.