Chlorophyll
A microscopic green solar power plant inside leaves that turns sunlight into food.
Definition Chlorophyll is a green pigment found in the cells of plants and algae. It plays a central role in photosynthesis by capturing solar energy and turning water and carbon dioxide into sugars like glucose.
Green Antennas That Catch Sunlight
Plants spread their wide leaves in all directions to catch as much sunlight as possible. When sunlight strikes the leaf surface, chlorophyll nestled inside microscopic organelles called chloroplasts acts like an antenna, capturing light energy.
Though sunlight looks white to our eyes, it actually contains every color of the rainbowβred, orange, yellow, green, blue, indigo, and violet. Out of all these wavelengths, chlorophyll heavily absorbs blue and red light. The trapped light energy becomes the vital power source plants need to make their own food.
Once chlorophyll captures light energy, it splits water molecules drawn from the roots into hydrogen and oxygen. The hydrogen combines with carbon dioxide to create glucose (plant food), while the leftover oxygen is released into the air, helping life on Earth breathe.
Why Plants Look Green
Why do plants with chlorophyll look green to us? It is because chlorophyll does not use green light for photosynthesis and bounces it away.
The color of any object we see is the color of light it reflects rather than absorbs. Chlorophyll eagerly takes in energy-packed blue and red light, but it reflects most green light. Because that bounced-off green light reaches our retinas, leaves look vibrant green to our eyes.
If chlorophyll absorbed every color of the rainbow, leaves would appear pitch black. If it reflected all light, they would look pure white. Thanks to chlorophyll's unique habit of using only what it needs and bouncing back green, forests across the world are filled with lush green foliage.
Where Does Chlorophyll Go in Autumn?
When autumn arrives, lush green landscapes turn into vibrant shades of red and gold. This happens because cooler weather and shorter daylight hours cause chlorophyll in the leaves to break down.
Leaves have always contained other pigments, like yellow carotenoids, alongside chlorophyll. During spring and summer, the sheer amount of green chlorophyll masks these yellow pigments, hiding them completely from sight.
As plants prepare for winter, they get ready to shed their leaves. To salvage precious nutrients, the plant breaks down its own chlorophyll and moves the nutrients to the stem. As the green curtain fades, the hidden yellow and orange pigments are finally revealed.
π€ Common misconceptions
All autumn leaf colors are newly produced when leaves change color.
Yellow pigments (carotenoids) were in the leaves all along through spring and summer. They were simply masked by chlorophyll and became visible once chlorophyll broke down. In contrast, red pigments (anthocyanins) are newly produced from trapped sugars in autumn.
π§Ί Where you meet it
Chlorophyll absorbs blue and red light to make food for plants, while reflecting green lightβwhich is why plants appear green to our eyes.