The key compound of Calvin cycle is

Options

A. PGA
B. PGAL
C. DHAP
D. DPGA

Answer

**Step-by-Step Solution:**

1. **Understanding the Calvin Cycle**: The Calvin cycle is a crucial process in photosynthesis that occurs in the stroma of chloroplasts in plants. It is responsible for the fixation of carbon dioxide into organic compounds.

2. **Key Components of the Calvin Cycle**: The cycle utilizes ATP and NADPH, which are energy carriers produced during the light-dependent reactions of photosynthesis. These components are essential for converting carbon dioxide into glucose.

3. **Initial Reaction**: The cycle begins with the enzyme Rubisco (Ribulose bisphosphate carboxylase/oxygenase) catalyzing the reaction between carbon dioxide and ribulose bisphosphate (RuBP), resulting in the formation of 3-phosphoglycerate (PGA).

4. **Conversion Steps**: The PGA is then phosphorylated and reduced through a series of steps to form glyceraldehyde 3-phosphate (G3P). This compound is crucial as it serves as a building block for glucose and other carbohydrates.

5. **Identifying the Key Compound**: Among the various compounds formed during the Calvin cycle, G3P (glyceraldehyde 3-phosphate) is identified as the key compound because it directly contributes to the synthesis of glucose, which is vital for the plant's energy needs.

6. **Conclusion**: Therefore, the key compound of the Calvin cycle is G3P (glyceraldehyde 3-phosphate), which is also known as PGAL (phosphoglyceraldehyde).

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