MCQ Detailed View

Chlorophyll is the primary pigment found in plants, algae, and some bacteria that enables photosynthesis, the process by which light energy is converted into chemical energy. The distinctive green color of chlorophyll comes from its porphyrin ring, a large, planar ring structure that binds a magnesium ion (Mg²⁺) at its center.

The central magnesium atom is crucial because it helps stabilize the porphyrin ring and allows chlorophyll to efficiently absorb light energy, particularly in the blue and red regions of the spectrum. This absorbed energy is then used to convert carbon dioxide and water into glucose and oxygen, sustaining plant life and providing oxygen for all aerobic organisms.

Different types of chlorophyll exist (e.g., chlorophyll-a, chlorophyll-b, chlorophyll-c), but all contain magnesium at the center of the molecule. Without magnesium, chlorophyll cannot function, and plants would be unable to perform photosynthesis effectively, leading to poor growth and loss of green coloration (a condition known as chlorosis).

Other options are incorrect:

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  Iron (Fe) is found in hemoglobin, not chlorophyll.

  
  


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  Calcium (Ca) is important for cell wall stability but not part of chlorophyll.

  
  


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  Potassium (K) regulates osmotic balance in cells but does not form part of the chlorophyll molecule.

  
  

In summary, the metal present in chlorophyll is magnesium, making it indispensable for light absorption, energy conversion, and life on Earth. Understanding this connection is fundamental in biology, agriculture, and plant sciences.