Only portions of visible light can be taken up by chlorophyll. True False
The correct answer and explanation is:
Correct Answer: True
Explanation (Approx. 300 words):
Chlorophyll, the green pigment found in plants, is essential for photosynthesis—the process by which plants convert light energy into chemical energy. However, chlorophyll does not absorb all wavelengths of visible light equally; it only absorbs specific portions of the visible light spectrum.
The visible light spectrum ranges from about 400 nanometers (violet) to 700 nanometers (red). Within this range, chlorophyll a and chlorophyll b (the two main types found in plants) absorb light most effectively in the blue-violet (around 430–450 nm) and red (around 640–680 nm) regions. However, they absorb very little light in the green region (around 500–550 nm), which is why plants appear green to our eyes—green light is reflected, not absorbed.
Because chlorophyll only takes up (absorbs) certain portions of the visible light spectrum, the statement is true. The unabsorbed light, especially in the green range, contributes to the coloration we observe in plant leaves.
This selective absorption plays a critical role in photosynthesis. The absorbed light excites electrons in the chlorophyll molecules, which then participate in a series of reactions to produce ATP and NADPH, the energy carriers that power the synthesis of glucose in the Calvin cycle.
Other pigments like carotenoids (which absorb light in the blue-green range and reflect yellow-orange light) help broaden the range of light a plant can use, but chlorophyll remains the primary pigment for capturing light energy.
In conclusion, chlorophyll absorbs only specific portions of visible light—primarily red and blue wavelengths—making the statement true. This characteristic defines how plants utilize solar energy and explains why most vegetation appears green. Understanding this principle is important for biology, agriculture, and environmental science, especially in optimizing plant growth under artificial light or in different natural conditions.