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Molecular Biology: Exploring the Basic Units of Life

What is Molecular Biology?

A molecule is a tiny particle made up of at least one atom. A water molecule, for instance, has two atoms of hydrogen and one oxygen atom, while DNA (found in the nucleus of every cell, it's the carrier of all the genetic information) is made up of many millions of carbon, oxygen, nitrogen, phosphorus, and hydrogen atoms. Molecular biologists study the functions and interactions of biological molecules inside a cell. These include DNA and RNA (which guides the way the body synthesizes protein, a major component of all plant and animal cells). Molecular biology is still a young science and is closely related to biochemistry and genetics, which also study cells on a molecular level.

When Rocio Diaz-Benjumea Benavides won her UNESCO-L'Oreal Fellowship in 2003, she was a cellular biologist specializing in cell biology and parasitology at Central Universidad de Venezuela in Caracas. Seven years later, she's shifted her location, her research focus, and her family situation.

Rocio Diaz-Benjumea Benavides

With her L'Oreal fellowship, Rocio was able to spend seven months in Seattle at the University of Washington, doing key experiments that allowed her to complete her Ph.D. in 2004. Her applications for a full time scientific position led her to a postdoctoral fellowship at Thomas Jefferson University in Philadelphia in 2005. Rocio quickly discovered that she had unique research expertise. "No one worked with the same parasites I had studied in Venezuela, which are common there, but very rare here." Rather than face the difficulty of studying a completely unfamiliar parasite, Rocio decided to switch her research to study a small protein, RhoA, that helps regulate how and when cells divide.

"We work with cells growing in Petri dishes. It's much less dangerous than working with parasites, which carry serious diseases. But the work is just as difficult-these cells take longer to grow, and get contaminated very easily," she explains. In Venezuela, her research had more limitations. "You had to work with what you had. Here, I can get whatever I need."

In basic science, "you constantly ask why, or how. It's fascinating how things work in a cell-everything is so tiny!" Rocio loves studying the RhoA protein because it regulates some of the processes that are altered when a cell becomes cancerous. "If we find out how RhoA is controlled, we could discover a way to help control cancer. That's very far away," she acknowledges, "but the basic science that I do is the first step in this process. We must find out what goes on in the cell before we can plan to cure someone. If I can ever get a result that could lead to a vaccine, it would be awesome."

Antonina Roll-Mecak

At the lab, she starts at 8:15 a.m., hours before some of her five colleagues, and leaves by 5 p.m. When her son was born in early 2009, Rocio appreciated being able to take three months of maternity leave. "My boss is really nice," she says, gratefully.

Rocio doesn't want to get discouraged after a lot of hard work on a project shows no results. "You just try to approach your goal in other ways, and keep your eye on the big picture. You have to be very patient, and always try, try again. Sometimes you ask yourself, why am I doing this?-nothing's happening," Rocio admits. "Then something works, and you forget everything else. The work is so interesting, it's amazing! You can't imagine until you're in this field."

Watching Cells Move

Like Rocio, Antonina Roll-Mecak is elated at seeing great data emerge on a project after lengthy hard work. In her case, the delight can now come from someone else's work, as well as her own. In January, Antonina became the head of her own lab-a big career advancement-at the U.S. National Institutes of Health (NIH). She's the head of the new Cell Biology and Biophysics Unit in the National Institute of Neurological Disorders and Stroke.

A 2006 UNESCO-L'Oreal Fellow, Antonina researches the cell's ability to move and respond to external signals. "Through a microscope, a cell is the image of a bustling city. Little organelles move on tracks, knowing how to get to the right place at the right time," she explains. "In a city, the train tracks are stable. A cell's tracks, called microtubules, keep adapting. They're being constantly taken apart and rebuilt. Our lab tries to understand what modulates the dynamic behavior of the microtubules. Many degenerative diseases are linked to mutations in proteins that form the cell's microtubular skeleton. If we can understand the features of a healthy cell's microtubulular structure, we could learn what changes them in a disease, and possibly how to prevent or treat it."

Antonina, whose research achievements recently led to her being named as a Searle Scholar, chose NIH because she's allowed to spend 80 percent of her time doing her own lab work. She appreciates NIH's graduate programs with U.S. and international universities, and especially its year-round program for high school and undergraduate students. To encourage her 16-year-old intern's increasing scientific interest, Antonina recommended a website ( with scientific animations of important cellular processes. "Her mom said Rachel watched it for days, and told her friends what molecules can do. She got hooked seeing visuals of proteins because they look cool," Antonina reports. Over lunch one day, Rachel shared a favorite quote: "If you love what you do, you will never work a single day in your life."

Antonina enjoys mentoring younger scientists. She has one biochemist and one physicist in her lab. She often talks with them about "the big picture-where their own projects are going. It's very exciting that my first postdoc got a fellowship on his first try! That feeling validates his work, and our lab's project. It's great to see someone so happy."

The prestige of becoming an Investigator brings major demands. "You walk into the new lab, and nothing's there. After you decide how to renovate the space and what equipment to order, you have to train your people so some knowledge transfers from you to them and they can become self-sufficient in the lab," Antonina recounts. For the first few months, she worked from 9 a.m. to 11p.m.

She's not complaining. "I think science is generally long hours. You really have to like the process, because it's all-consuming. If you love it, it doesn't feel like a job. It just feels like your calling," Antonina says happily.

The "Aha!" Moment

Elizabeth Blackburn's calling showed in her childhood love of animals. "There's such beauty to creatures and animals. I still feel that in science," says the Morris Herztstein Professor of Biology and Physiology at the University of California, San Francisco, and 2008 L'Oréal-UNESCO laureate.

Elizabeth always knew she'd be a scientist. At 10 years old, she'd imagine "the glamorous life of a scientist-probably not a realistic view," she reflects. Curious about chemical activity inside cells, she was eager to understand molecules. That specialty, still part of biochemistry in the 1960s, was about to become Molecular Biology.

During Ph.D. studies at Cambridge University, she became fascinated with the long strips of DNA that form chromosomes. "They're like shoelaces with a cap (telomere) at the end that protects all their genetic information. I wanted to sequence the DNA at the end of each chromosome," Elizabeth remembers.

Micheline Pelletier for L'Oréal Corporate Foundation
Elizabeth Blackburn

Years of observation convinced her that as telomeres wear down and are rebuilt, some kind of enzyme is probably causing that renewal activity. "Science sometimes brings a moment when everything clicks into place. You suddenly say, 'Aha! I can see it-this is really something new.' That's why, once you become a scientist, you can never stop."

It was an 'aha!' moment when Elizabeth first saw the pattern of the enzyme that repairs DNA ends. She and her lab team named their 1985 discovery "telomerase" because it protects the telomeres. She's elated that the word is in Webster's Dictionary.

Elizabeth studies telomerase's role in various diseases. When DNA doesn't have enough protection at its tips, it can't renew itself, and the cell stops dividing and replenishing tissues. This weakens the immune system, and may also be related to heart disease. Telomerase levels are very high in cancer cells, so Elizabeth hopes this research can someday be applied to treating cancer.

She appreciates the scientist's combination of solitary, creative thinking time, and interactions with people. "That's the reality of biological and clinical research. It's intriguing how those play off against each other." Having done much of her earlier work alone, Elizabeth finds frequent collaboration "a very exciting, enjoyable new part of where our science is. I wake up every day and think about what's going on in our lab, what new directions we're working on. Things are very exciting in research now. You're always learning more about what makes us tick. To me, that's part of the fascination," Elizabeth reflects.

The fascination is mutual. Her scientific contributions have brought not only a new dictionary word, but an even rarer reward: the 2009 Nobel Prize in Medicine.