Chapter 10, Problem 1Q

Summary Introduction

To review:

The rate of photosynthesis increases in the leaf exposed to higher light intensities.

Given:

The graphs representing the rate of photosynthesis as a function of the intensity of light.

Introduction:

The process of photosynthesis is light dependent. Photosynthesis converts light energy into chemical energy. The rate of photosynthesis will increase if the leaves are exposed to the higher intensity of light.

Explanation of Solution

Photosynthesis is a light-dependent process. This process uses light energy to produce carbohydrate and provide energy to plant for various metabolic activities taking place in the plant. This process produces carbohydrate by using light and carbon dioxide.

The rate of photosynthesis increases when there are higher light intensities. The leaves, which are exposed to the higher intensity of light, show high rate of photosynthesis. At low light intensity, the leaves will show a decrease in the rate of photosynthesis. The leaves with the larger surface area and high density of chlorophyll will show a high rate of photosynthesis as they can absorb more light.

From the given graphs, it is clearly visible that both the plants show increasing rate of photosynthesis in high intensity of light (shown by orange line) and rate of photosynthesis is low in low intensity of light (shown by purple line). The photosynthesis is directly proportional to the intensity of light, so the curves of photosynthesis increase with increasing light intensities.

This occurs because of the increase in the rate of light-dependent reactions, which in turn results in the increase in photosynthesis rate. However, the rate of photosynthesis is dependent on other factors like temperature and carbon dioxide concentration. Therefore, with further increase in light intensity, the photosynthesis rate does not rise further and eventually plateaus.

Conclusion

Thus, it can be concluded that photosynthesis is a light-dependent process. The rate of photosynthesis is directly proportional to the intensity of the light but to a certain extent only, as photosynthesis is controlled by various other factors also.