The cell game

The cell game

Fingernails grow. Hair gets longer. Skin heals. Bones mend. A virus abates. An infection is quashed. As if a wizard's wand waves to make it so. Inside the human body are clues to why this magic occurs.

It's all in the cells.

We're all composed of microscopic cells -- some 10 trillion cells. Muscle cells, liver cells, brain cells and a couple hundred more types of cells.

Inside each cell are workhorses known as enzymes. Think of each cell as a miniature chemical reactor made possible by enzymes. The enzymes speed up the chemical reactions as they break molecules apart, stitch the molecules together and jettison others that are no longer needed. Our DNA -- deoxyribonucleic acid -- provides a master blueprint to guide cells in producing new enzymes. Cells use enzymes to grow, reproduce and create energy. Enzymes are one class of proteins being made and only part of the cellular story. An intricate control system ensures genes are turned on in the right tissue at the right time and produce the correct amount of protein for the cell to function properly.

In turn, the cells tell each other what to do, synchronizing every operation within our bodies. Cells create messages, and then transcribe and deliver them within each cell so every part knows its role.

There's a lot more going on. While the enzymes are zipping around making things happen at the behest of our cells interpreting directions from our DNA, a substance known as ATP -- short for adenosine 5-triphosphate -- stores chemical energy within cells. Each ATP molecule is recycled 2,000 to 3,000 times during a single day, and like electricity, it is a source of energy that cannot be stored and must be used right away. So if you weigh around 150 pounds, your own body might be creating 88 pounds of ATP each day. An electron transport chain, resembling a relay team, passes electrons from one compound to the next as it sets the stage for ATP production. It's a busy place inside cells.

But we can't see all these cellular and molecular processes as they accomplish dizzying sequences of action. They're just too small. Pluck a hair from your head, (gray or otherwise) and take a look. The strand might be a tenth of a millimeter, which is 100 microns. A cell might be only 10 microns -- really, really tiny. Teaching students about cells and more importantly, what occurs inside them, represents a challenge. How do you portray something that's not readily visible? How do you engage students in not just memorizing terms for a test, but in truly understanding molecules, cells, proteins, enzymes and their amazing actions occurring within plants, animals and people?

Enter The Virtual Cell

First, eerie strains of music, then the dark screen comes to life. Opening titles roll. "Virtual Cell Presents" appears within a cosmic blue circle against a black background. The name of the movie comes into view. Blue, transparent oval images wiggle within a spotlight that expands into blindingly white light. An articulate female narrator sets the stage as the action begins.

Next, the screen becomes a kaleidoscope of yellow, blue, purple, magenta and green with colorful capsules, floating strands of ribbon and kidney-shaped geometric forms. The mini-movie lasts three to five minutes. During the film, animation breathes 3-D life and action to amplified views of cellular and molecular processes, helping students visualize what happens inside cells. Eight of these mini-movies, known as the Virtual Cell Animation Collection, were conceived, produced and finally premiered at North Dakota State University. Visiting this Web-based virtual cell allows students and teachers to travel inside these cellular worlds. The First Look section includes photos to introduce each topic. Another section, Advanced Look, provides in-depth information. Click on The Movie. As the music swells, scientific discovery unfolds in each scene. It's groundbreaking stuff in education, enough to be recognized by the National Science Foundation -- the arbiter of what's going on in science and research -- with a link on the foundation's Web site section on discoveries.

The story, however, begins long before that first frame. Bringing this animated world to life is a long process, starting with -- what else -- a script. Phil McClean, who teaches genetics and plant molecular genetics at NDSU, writes narratives to describe what goes on in a particular biological process. Then an artist creates objects based on the narrative. In most cases, the cast of characters in the mini-movies are actual shapes that have been previously discovered using X-ray crystallography and other scientific techniques. In instances where molecular models are not readily available, the artist goes to work, employing imagination to render images for the screen.

The mini-movies are more than just educational. They're gorgeous, in part due to Maya(R) 3-D graphics software from Autodesk(R), a software so powerful it has received its own Academy Award in 2003. It's been used to create blockbusters like Star Wars, Lord of the Rings, and Chronicles of Narnia. Without this software, the NDSU project would not be possible, so it's significant that professor Jeff Clark and visualization expert Aaron Bergstrom secured software licenses and training scholarships for NDSU to use it.

But good software doesn't mean the art phase of virtual cell computer animations is any less labor intensive. An artist may spend 200 hours on each detailed step, and then there's another 40 hours of post-production to edit, add titles, narration and sound effects. Artists who can illustrate biological processes are a specialized lot, but people like Christina Johnson are out there. Johnson came to NDSU with visions of majoring in biotechnology. But experiences in lab settings made one thing clear -- it wasn't for her. She switched to her avocation, graduating NDSU as an art major with a strong foundation in science. The convergence of art and science makes the virtual cell animations unique. "We try to drive home that these are spatial processes. We want them to understand that it is happening in space and that it is three-dimensional," says Johnson. "We'd like to think that we present these things in a way that is entertaining to some extent. We try to keep in mind cinematically what they look like. Is it interesting to watch?"

To understand how the animations are built, picture a skeletal or wire frame drawn onto a computer screen. Then plot the frame's movement millimeter by millimeter. Add layer upon layer of texture to make the object recognizable. Art, cell biology, math and computer science are used to blend the frames, objects and associated landscapes into movies. Crafting such animations requires hefty computer processing power. NDSU's Center for High Performance Computing, capable of 500 billion calculations per second, makes these movies spring to life. In some respects, the animations are scene stealers. Originally created to guide programmers developing educational computer game modules to teach biology, the animations assumed a life of their own.

A Hit With Audiences

Audiences know what they like. There's even a burgeoning Virtual Cell fan club around the country. "The Virtual Cell animations engage my students, plain and simple," says a professor at Marquette University in Milwaukee. "I know that it takes tons of planning, great design and skill to create science animations of this quality, but my students don't see that -- they see the science, which is exactly where I want their attention to be focused."

Although anecdotal evidence is useful, scientific proof that virtual cell animations enhance student learning underscores their value. "We build worlds to develop an environment where the student can learn to solve problems," says McClean. A team of researchers from across campus -- McClean, computer scientist Brian Slator, Lisa Daniels from education, statistics professor Jeff Terpstra, and Alan White, a former NDSU biology professor -- show that students who use the movie animations actually learn the content material better than students who don't use them.

Though the project earlier received attention in publications such as Cell Biology Education, a mention in the Netwatch section of Science magazine in late 2005 raised its profile. The brief article offers a movie critic's review, albeit a scientific one, about NDSU's Virtual Cell Animation Collection. After the article ran, the virtual cell Web site logged more than 100 new users. Based on the magazine's high-profile exposure, universities in Wisconsin, Utah, Washington, North Carolina and Colorado are interested in collaborating with NDSU on the project. Translations into French and Spanish are possible.

As for sequels to The Virtual Cell, more mini-movies are being created to feature additional molecular and cellular processes. The NDSU team that developed them is investigating whether the animations could be adapted to changing technology. How, for example, might they be configured so students could download them for viewing on an iPod?

Whatever form The Virtual Cell Animation Collection takes in the future, be certain that molecules, enzymes and their assorted scientific partners will continue to be cast in starring roles. No stunt doubles allowed.

-- C. Renner