Using a Virtual Tissue Culture System To Assist Students in Understanding Life at the Cellular Level

Almost any person would describe a grasshopper, sunflower, evergreen tree, or a spider monkey as alive and a rock, water, or air as non-living. Yet, life resists a simple, one-sentence definition because it is associated with numerous emergent properties. Biologists recognize living things via a checklist of these emergent properties: reproduction, growth and development, energy utilization, response to the environment, and adaptation. Additionally, because these properties of life "emerge" from complex organization, biologists also add the characteristic of possessing "order" to their list of criteria. The higher orders of life reflect the assembly of atoms, molecules, macromolecules, organelles, cells, tissues, organs, organ systems, into an animated individual. In every biology course ever taught in our nation's classrooms, and in every biology book ever published, students are taught about the "cell." It is the cell that is dubbed the highest and most prestigious of all things in the list of "order" because it is the lowest level of structure capable of life itself. Indeed, most students will recite with vigor, and even remember, the definition of the cell as "the basic structural and functional unit of all life." The cell is as fundamental to biology as the atom is to chemistry. Truly, everything an organism does occurs fundamentally at the cellular level: from transporting oxygen in a red blood cell to providing tensile strength to lift a dumbbell via tendons, ligaments, and muscles, or regulating glucose concentration in the blood via pancreatic regulation of insulin secretion. Yet, what do we do to have our students actually think about, and understand this key element of life? The answer is not too much, beyond memorizing its definition, or matching organelles to their function on a test. Maybe it's because it's easier to think of life at the organismic level. Maybe it is because cells are small--typical mammalian cells range from 1 to 100 [micro]m in diameter, and, therefore, are visible only under the microscope. Maybe it's because most basic biology labs do not perform tissue culture or have stateofthe-art microscopic tools to provide students access to seeing cells in their living state. Indeed, a living paramecium or amoeba, here or there, may be observed. Sure, students routinely look at bacterial preps, stain their cheek cells with methylene blue, or worse yet, look at preserved slides; but is this enough? Is it enough to list organelles on the board and have students memorize the function of each organelle, without any clue as to "how" the endoplasmic reticulum (ER), Golgi, and lysosome actually work to help sustain life at the cellular level? Is it enough to teach students about a cell by merely using color-coded diagrams of box-like representations in packaged textbooks? Using this approach, we are not allowing our students the opportunity to understand the essence of cellular life. Moreover, we are misguiding our students by creating the misconception that all cells are the same and not relating another important message, or key concept in biology: that the structure of each cell relates to its distinct function. A red blood cell is shaped like a donut, a neuron looks like a branching wire, a sperm looks like a harpoon, rods and cones are shaped like huge antennae, and epithelial cells are either cuboidal, columnar, or squamous to perform their unique cellular work (McLaughlin, 2001). Biology students of today must appreciate that cells actually are alive! They must see a cell as carrying out life-sustaining functions, and that each one is a "living" entity unto itself. In today's world, students must be able to appreciate, and critically think about life at the cellular level. Why? The study of diseases (like cancer, diabetes, Alzheimer's, multiple sclerosis, and bipolar disorder), epidemics (the influenza, AIDS, or SARS, not to mention drug addiction, and obesity), or the loss of biodiversity (due to eutrophication of lakes, rivers, and ponds); each requires an understanding of unique cell types and their specific biology and physiology. …