What is the Difference Between Light Reaction and Calvin Cycle?

The difference between the light reaction and the Calvin cycle lies in their dependence on light and their specific roles in photosynthesis. Here are the main differences:

• Dependence on Light: The light reaction is light-dependent, meaning it can only occur in the presence of light. In contrast, the Calvin cycle is light-independent and can take place in the presence or absence of light.
• Location: The light reaction takes place in the thylakoid membranes of chloroplasts, while the Calvin cycle occurs in the stroma of chloroplasts.
• Function: The light reaction captures light energy and converts it into chemical energy in the form of ATP and NADPH, which are required for the Calvin cycle. The Calvin cycle, also known as the dark reaction, uses the energy from ATP and NADPH to convert carbon dioxide into glucose (a simple sugar).
• End Products: The end products of the light reaction are ATP and NADPH, while the end product of the Calvin cycle is glucose.

In summary, the light reaction is the initial stage of photosynthesis that traps light energy, while the Calvin cycle is the second step that uses the energy from the light reaction to synthesize glucose from carbon dioxide.

Comparative Table: Light Reaction vs Calvin Cycle

The light reaction and Calvin cycle are two distinct stages of photosynthesis. Here is a table comparing their differences:

In summary, the light reaction depends on sunlight and occurs in the thylakoid membranes, while the Calvin cycle is light-independent and takes place in the stroma. The light reaction produces ATP and NADPH, which are then used in the Calvin cycle to convert carbon dioxide into glucose.