Sunday, July 31, 2011

Cells and biology

I recently borrowed a book from my sister who has a Master's in biology, Zoology by Dorit, Walker and Barnes, about 900 pages, intended audience is college biology students I believe. I've been reading it over the summer, and I must say it's the most interesting book I've read in years. I can't recall the last time I've learned so much in such a short time span.

The book goes through what stuff cells are made of, how respiration and cell division works, how protein compounds are made, how it is thought various solutions to problems evolved, how various features of species stem from physical limits and constraints in the environment. For instance, tiny animals don't have lungs. They don't need them because no part of their internal body is ever far from air or water. The complicated blood and lung system of humans is really an extraneous necessity required by our huge size.

The book then covers the various animal groups one by one. As it turns out, most of the stuff I at least tended to associate with humans and higher animals is really nothing new. Sex was not invented with the monkeys. Also air is a pretty inhospitable environment, as the book puts it, every animal not living in water is constantly living at the risk of desiccation.

One of the things I've learned is that the world of cells is an extremely complicated world in its own. A big animal, like a human, is really a big blob of cooperating cells, each cell being a living being in its own right, although of course dependent on the others. The cells in your foot are dependent on the cells in your mouth to swallow food and the cells in your intestine for taking in nutrients from the soup that passes through. And vice versa, no feet means no catching food, at least in nature.

It's a purpose of life, feeding your cells, and a good one I believe. But each cell is actually a pretty complex thing, with small bacteria-like sub-components called organelles like the mithocondria that take in oxygen and various other stuff and output cell fuel, ATP, not to mention the complex chemical machinery that replicates and executes the DNA code. Cells have a life of their own. For instance some cells in the body feed on the bacteria and other stuff that enters the tissue by engulfing and digesting it; that's an important aspect of the immune system.

Structure of a typical animal cell (from Wikipedia)

Likewise, the interaction between the cells is highly developed, not the least keeping in mind that the chemical cell machinery must at all stages be able to self-repair. It is also grown, unlike a human-made machine in the macro world assembled from ready-made pieces, all animals and all their parts must be made from tiny single cells that collect nutrients and out of them build bigger structures.

And everything is controlled by the laws of physics and long self-replicating double-helix strands of 4-character code that specifies what happens when.

It is simply amazing.


  1. I came across this blog post on one of my Sparks feeds on Google+ and it just astounds me that someone your age (which happens to be the same as my age) didn't already know most of this prior to reading that textbook. I am a high school biology teacher and I teach every one of these concepts to my 14-year-old students (I wish they had your enthusiasm about learning). But it makes me wonder how many other adults don't know these simple concepts about how living organisms are able to survive. I had just assumed that everyone know these things, so your post really opened my eyes. Thanks!

  2. Well, besides the classes in school, I had one year of biology in high school (in Denmark). As I recall, it was mostly focused on things you can see, understanding how animals and plants interact, though of course DNA and cells and respiration was covered superficially.

    Many of these concepts were known to me beforehand, just not at the detail level in this book. I think the detail level is what really made it interesting to me since they moved my understanding from a state of knowing there some concepts to a state of having some kind of grasp of why it actually fits together.

    I mean, I think I now understand (at a high level with lots of holes, of course) why living things are actually alive, as a natural consequence of the laws of physics.

    My high-school understanding of e.g. DNA was more everybody's got it, it determines how organisms are built and go about their living, and it undergoes mutations over time causing evolution, and that's it. It's hard to really appreciate the beauty of the whole thing at that level, for me at least. Maybe you manage to do it anyway for your students, I hope so. I think you'd probably have to have had a couple of classes in organic chemistry to understand the book I read, doubt you are teaching your 14-year olds down to the level of the chemical reactions in copying mRNA. :)

  3. Not everyone learns Biology at their school, it is important to know the common base of Biology, although this generation just do not care for this kind of things, they just accept it as it is, without trying to improve or change what they got.

    You can just see it by the "fear" in the eyes of the Facebook users whenever Facebook changes their main page, even if it`s for the better.

    This days its kinda hard to see where this "facebook generation" goes to, while I find more people lacking basic English knowledge as far as even saying one two three..

    They don`t care about what will happen, they are just happy to sit in front of their pc all day long.

    And thats your answer for "why people do not know basic of biology", cause they just don`t care.