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The Sugars of Life

SUGAR—likely you use it to sweeten anything from cakes to coffee. But did you know that sugar may fuel a revolution in biology that could equal the one triggered by the discovery of DNA?

In recent times scientists have studied how cells use simple sugars such as glucose to build giant molecules “that rival DNA and proteins in size and complexity,” says the journal New Scientist. “Sugars are involved in almost every aspect of biology, from recognising pathogens, to blood clotting, to enabling sperm to penetrate an ovum.” At the same time, defects in their synthesis have been linked to a growing number of diseases, such as muscular dystrophy and rheumatoid arthritis. “Biologists are only just beginning to get to grips with these sugars,” says the report, “but as they do, they are finding themselves having to rethink long-held ideas about how life works.”

Scientists have coined the word “glycome” to refer to the full set of sugars that a cell or an organism makes, just as the word “genome” embraces the full complement of genes. A cell’s glycome, however, is “probably many thousands of times more complex than the genome,” states Ajit Varki, director of the Glycobiology Research and Training Center at the University of California, San Diego, U.S.A. Why is the glycome so complex?

Within cells, simple sugars—monosaccharides—link together to form polysaccharides. These, in turn, are assembled into giant molecules that may contain more than 200 units of simpler sugars. Because of the three-dimensional way in which these sugars are configured, which is key to their function, “a sugar made of a mere six units can have a staggering 12 billion possible versions,” says New Scientist.

Describing the daunting challenges facing researchers in this emerging field called glycobiology, Varki said: “It’s like we’ve just discovered the continent of North America. Now we have to send out scouting parties to find out how big this is.”

Clearly, the complex mechanisms of the living cell bespeak an intelligence of the highest order. In the case of many, this fact engenders a feeling of reverential awe. Is that how you feel?—Revelation 4:11.