Inside Science

Life depends on chemical reactions of plants, algae and microbes

CorrespondentJanuary 5, 2014 

Dr. David J. Kroll is Director of Strategic Science Communications at the North Carolina Museum of Natural Sciences and Adjunct Associate Professor of English at North Carolina State University.


What do you think of when hearing the words chemistry or chemicals?

A smoke-belching factory? Toxic substances in drinking water? The explosive reaction of Mentos and a two-liter bottle of soda?

Chemistry has existed in nature long before people in lab coats mixed up colored liquids in fancy glass flasks.

Just look up and around you. Virtually all life on Earth depends on plants, algae and specialized microbes performing chemical reactions – photosynthesis – that capture the light energy from the sun to produce life-giving chemicals – the unlocking of oxygen from water and the capturing of carbon dioxide from the air to create glucose and other carbohydrates. In most cases, this light-capturing conversion begins with a green pigment in chloroplasts called chlorophyll, itself a magnesium-containing chemical with similarities to heme in our hemoglobin.

We in North Carolina are fortunate to have more than 4,000 species of these chemical factories – plants. But we often don’t appreciate that photosynthesis is also performed in the ocean by microscopic organisms called phytoplankton. In fact, scientists estimate that more than half of the Earth’s oxygen is generated from ocean photosynthesis. And just as terrestrial life depends on plants as a food source, marine life depends similarly on phytoplankton.

But the living chemistry of the food chain provides us with far more than the basic necessities of life. Plants and microorganisms can make other chemicals called secondary metabolites or natural products. In most cases, the organism makes such chemicals because they are beneficial, for example, in producing color to attract pollinating insects.

Indigofera plants were brought by Caribbean colonists to South Carolina because its natural dye, indigo, could be used to color textiles. Are you wearing blue jeans? This plant-based dye is still used to color denim. In the course of making a protein building block, the amino acid tryptophan, the indigo plant’s chemical factory redirects a chemical called indole to create a beneficial color for its flowers.

Plants can also make chemicals that we use as medicines. The opium poppy is a widely known example that gives us morphine, still the most effective drug for treating severe pain. Another poppy chemical, thebaine, can also be used by our modern chemical factories to make related painkillers such as oxycodone, as well as naloxone, the antidote to opioid overdose.

Chemistry is truly all around us – yet another benefit of our natural world.

Dr. David Kroll is director of Strategic Science Communications at the N.C. Museum of Natural Sciences and adjunct associate professor of English at N.C. State University. Follow him on Twitter @DavidKroll.

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