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How Small Is Small?
By Antonio Garcia
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A series of crab larva pictures zooming in to show bacteria in the larva's eye
What's the smallest thing you can think of? A cookie crumb? A grain of sand? A germ?
With the help of a special microscope called a scanning force microscope, I can see some of the tiniest things on earth. I can peer inside a single cell to see the shapes of the individual building blocks of that cell. Just how tiny is that? To give you an idea, a person is made up of about 10 trillion (10,000,000,000) human cells. Now imagine looking inside one of those cells at a single building block just 10 billionths of a meter -- or a nanometer -- long!The Mighty Tiny
I study microscopic fungi called yeast. I'm especially
interested in the walls of the yeast cells. They are amazingly strong,
making yeast cells one of the toughest cells to break open. The scanning
force microscope let's me see how the cell walls are built so I can figure
out why they're so strong. One of the building blocks of the yeast cell
wall is called a glucan [glue-can]. Glucans are very sturdy and
weave together tightly to form a tough ball protecting the inside of the
yeast cell. Another material called chitin [kite-in] is used as
mortar or cement to patch up any holes in the weave.
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Yeast Cells Courtesy of the Digital Learning Center for Microbial Ecology Microbe Zoo
Why Yeasts?
Some harmless yeasts are always growing on
humans -- especially on your skin and in your intestines. But sometimes
yeasts can grow out of control, multiplying very quickly. This is called
a yeast infection. One of the reasons for studying yeast cell wall construction
is to figure out ways to punch holes in the cell wall to fight these infections.
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May the force be with you!
Want a glimpse of the teeny tiny? My co-workers and I at Arizona State University are creating a new way to run scanning force microscopes using the World Wide Web. People across the country will soon be able to operate a scanning force microscope through our web site. Science classes in schools and colleges can either join us in our research or investigate questions of their own. How does it work? One class at a time will be scheduled to operate the microscope over the World Wide Web, but everyone else in the world with a computer and browser will be able to watch the microscope pictures as they are being collected by the microscope. Although it was written for older folks, you may want to visit us at our web site (http://invsee.eas.asu.edu) to see more pictures of very small things. I think you will agree with me that, "It's a nanoworld after all!" |
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Antonio Garcia is an associate professor of chemical and bioengineering at Arizona State University in Tempe, Arizona. He writes:
On President Lincoln's birthday in 1962, my mother, brothers, sister, and I (the youngest at 2 years of age) moved to the United States from Cuba. After my father joined us, we settled in New Jersey. We came with nothing but some clothes and joined the long tradition of immigrants who come to the United States wanting to make a better life for themselves. I became fascinated with science and especially chemistry when I began reading the science fiction and science fact books by another immigrant who came to the United States, Isaac Asimov. When I was about 5 years old, I got a battery-powered car set with an oval-shaped track for Christmas. After playing with it for several days, I was starting to get bored. Then a car spun off the track, and the batteries fell out. By accident, I put both batteries back the wrong way, causing the car to run backwards on the track. I remember excitedly showing my family how I made the car go backwards. I guess this memory is so vivid because I felt that I had done something new and was proud of having somehow outwitted the toy maker. As a grown-up, I enjoy studying and inventing things that no one else has ever known or that others had thought impossible to do. It is great fun for me to have a day where, like the character in Alice in Wonderland, "I try to think of at least a hundred impossible things before breakfast."
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