Cells make up all known life

 kw: book reviews, nonfiction, science, cytology, biological cells

When I was a pre-teen a family friend, a biologist at the University of Utah, gave me two little bottles. They were powdered dyes, Eosin and Carmine. Both were red powders, but I learned that Eosin is more acidic, so the two dyes stain biological materials differently. I used them sometimes, with my little microscope, but I usually examined things in their unstained state.

If you have a microscope available, and some glass slides and cover slips, try this: using an ordinary teaspoon, gently scrape inside your cheek, and put a drop of the slightly milky fluid on a slide. Drop a cover slip on top and have a look, first at 100x. The grayish blobs are epithelial cells. If you have a dye such as Mauve (an Aniline dye) available, you can use that, and then you might see something like this:

For a sense of scale, these cells are typically about 50 microns wide (0.05 mm). If you are viewing this on a laptop screen they probably appear about a half inch across (12 mm), and on a phone, perhaps half that size. So this image is about 240x on a laptop, 100-120x on a phone.

If you don't have any kind of dye, a drop of household iodine will make a slightly brown stain on the nucleus.

Cells such as these have lots going on inside them, but hardly anything besides the nucleus is visible with an optical microscope. The wavelength of yellow-green light, where we see best, is just over half a micron (550 nm). The best optical systems cannot distinguish items smaller than that.

In the 1960's I began to see articles about cell substructures in Scientific American (we subscribed), with images taken with an electron microscope. I was enthralled! This image of a cell similar to the cheek cells above is from Pocket Dentistry. It has some cellular substructures (organelles) labeled.

The organelles and what they do is outlined—briefly!—in early chapters of The Song of the Cell: An Exploration of Medicine and the New Human by Siddhartha Mukherjee, a cancer physician, researcher and professor of medicine in New York City.

Looked at in detail, a cell is like a city. Consider a few functions of a well-run city: traffic control; waste management; distribution of energy, food, fuel and supplies; manufacturing; libraries, including the knowledge base for manufacturing; and policing. In a cell:

• The proteins actin and myosin work together to produce movement, such as in muscles. Cities don't typically move around, but in a cell the same proteins are used to shuttle materials about: a transportation system.
• Some vacuoles gather waste products, are shuttled to the cell membrane, and deposit them outside the cell: waste management.
• Mitochondria produce energy, at the same time taking in oxygen and excreting carbon dioxide: energy production and distribution.
• The DNA in the nucleus is the cell's library of instructions, both how to make proteins and how they are linked up.
• Misfolded and other "problem" proteins are gathered into lysosomes and destroyed or recycled: a police function.

The author takes us through the history of the discovery of the cell, with mini-biographies of key researchers such as Rudolf Virchow, who stated that "all life is made of cells" and that normal and abnormal issues in creatures stemmed from normal or abnormal functions of cells. The bulk of the book consists of chapters titled The Guardian Cell (neutrophils in the immune system), The Contemplating Cell (neurons), The Renewing Cell (stem cells), and so forth. The book is a mini-education in organismic cytology.

Dr. Mukherjee's life work is with cancer ("The Selfish Cell"), and the mysteries of the many, many varieties of cancer. Cancer isn't one malady, it is a behavior expressed by numerous kinds of cells that get off-balance; cells don't just have a "grow this much and then slow down" or "…and then divide" mechanism, they have (a few or several) opposing mechanisms which rise and fall in concert to regulate such things. In a car, there is the gas pedal and the brake pedal, which the driver operates in synchrony to regulate speed. 

My first accident occurred when I was, age 15, allowed to put the car away by moving it from the driveway into the garage, on a rainy day. My foot slipped off the brake and floored the gas pedal, and the car leapt through the garage and burst halfway through the back wall. Cancer is like that: floored accelerator, no brakes. My father was very mechanical: he and I had several days of father-son bonding while we pulled apart the broken wall and repaired it. He taught me a lot of carpentry and other skills that week.

One goal of the book is the concept of "the new human", meaning a human with renewed tissues or organs, so the rest of the body can continue living. The author's "poster child" is Emily Whitehead. To quote the caption on her photo:

"…the first child treated at the Children's Hospital of Philadelphia for relapsed, refractory acute lymphoblastic leukemia (ALL)…[her] T cells were extracted, genetically modified to "weaponize" them against her cancer, and reinfused into her body."

She is still in good health eleven years later. She is a "new human", with something new in her immune system. From a cellular viewpoint, regulating cells is a step beyond "genetic engineering".

When I was in 8th grade I wanted to be a biologist, specifically, a cytologist, someone who studies cells. At a school assembly, the headmaster (I was in a private school using a British system) asked each one of us what we wanted to be. My fellow students wanted to be doctors, lawyers, professors, and so forth. When my turn came I said, "A cytologist." The headmaster nodded agreeably and said, "A psychologist, how nice!" I didn't think it wise to explain at that point. 

Reading this book helped me realize how utterly complex is the living cell! As I wrote above, it is easily as full of numerous functions as a city, a city that runs itself. And the trillions of mini-metropolises that make up our bodies usually operate almost flawlessly! It's an enjoyable and fulfilling book.