Type of Light for Photosynthesis
Answer: B. Blue and red
Photosynthesis is the process by which plants convert light energy into chemical energy, which is then used to fuel various plant functions. Light is a crucial factor in photosynthesis, and certain colors of light are more effective than others. The type of light that is most effective for photosynthesis to occur is a combination of blue and red light.
Explanation:
To understand why blue and red light are effective for photosynthesis, it is important to know about pigments called chlorophylls, which are responsible for capturing light energy. The two main types of chlorophylls, chlorophyll a and chlorophyll b, have different absorption spectra.
1. Chlorophyll absorption:
- Chlorophyll a absorbs light most efficiently in the red and blue regions of the visible spectrum.
- Chlorophyll b absorbs light most efficiently in the blue and red-orange regions of the visible spectrum.
2. Action spectrum:
- The action spectrum of photosynthesis shows the rate of photosynthesis at different wavelengths of light.
- The action spectrum reveals that chlorophyll a and chlorophyll b have peak absorption in the blue and red regions of the spectrum.
3. Red and blue light:
- Red light (wavelengths around 660 nm) and blue light (wavelengths around 430 nm) are most efficiently absorbed by chlorophyll a and chlorophyll b.
- These wavelengths of light provide the highest energy to drive the photosynthetic reactions.
4. Other colors:
- Ultraviolet and blue light (shorter wavelengths) are also absorbed by chlorophylls but to a lesser extent.
- Green and yellow light (wavelengths around 500-600 nm) are poorly absorbed by chlorophylls and are reflected, which is why plants appear green.
In summary, blue and red light are the most effective for photosynthesis because they are absorbed most efficiently by chlorophyll a and chlorophyll b. This absorption of light energy allows plants to carry out the process of photosynthesis, producing glucose and oxygen as byproducts.