Models in science
We have no idea about the 'real' nature of things … The function of modeling is to arrive at descriptions which are useful. Richard Bandler and John Grinder. (1979)
We'll start with the basics. We need to know what a model is, and how it will be used in our class. We'll use a lot of different kinds of models to help us understand what we are learning. Understanding the way we use models will be an important basis for completing this class.
Microscopes and Cells
The eye of a human being is a microscope,
and makes everything seem bigger. Khalil Gibran
It is important that we realize how far we have come in such a short time. It wasn't so long ago that we didn't know anything about the invisible world around us - the world of cells and microbes. The development of the microscope opened up a whole new world to biologists, and allowed us to discover so much about life.
Organelles & Cell Structure
In Darwin's time all of biology was a black box: not only the cell, or the eye, or digestion, or immunity, but every biological structure and function because, ultimately, no one could explain how biological processes occurred. Michael Behe
So, now that scientists can see inside a cell, what do all of the 'innards' do? This involved lots of experimentation and analysis, and ultimately lead to our understanding a good deal about life and what it means to be alive. There are still mysteries that have yet to be answered, including How did life start?. But that's getting ahead of ourselves.
I like homeostasis. Sheldon Cooper
All organisms need to maintain internal stability to survive. We need a constant stream of food, oxygen, energy, waste removal, and more to stay alive. A lack of just one of these (in fact, even an excess of one of these) throws an organism out-of-balance, and will ultimately lead to death. There are some external factors that need to be controlled as well; sunlight (too much and you cook, not enough and you die); temperature (organisms live in a narrow band of temperatures), pH (the acidity/baseness of our environment; all of these factors must remain stable for an organism to survive. We'll look at these and see how organisms maintain or create that stability.
When preparing to travel, layout all your clothes and all your money. Then take half the clothes, and double the money. Susan Heller
Cells need to move materials throughout their cytoplasm - sometimes to bring substances into the cell, and sometimes to excrete waste products. These transport systems will be discussed and explored in this section.
I just want to say one word to you. Just one word. Plastics. Mr. McGuire
All living things require four types of large molecules to survive. These are the macromolecules of life. Macromolecules are molecules that contain a very large number of atoms. We'll take a look at each of these types of molecules, and determine what each does for the cell, and where they are found.
Molecular biology is essentially the practice of biochemistry without a license. Erwin Chargaff
The Central Dogma of Biology may be simply stated as "DNA males RNA makes Prootein", but the full implications and explanation of this is anything but simple. Scientists needed to first understand the role Nucleic Acids play in the cell, then they needed to understand the structure. Once the structure was understood, Replication and Transcription could be tackled, and only then could the concept of how the DNA actually contains the instructions for Protein Synthesis. Considering the complexity, it is amazing that this discovery process didn't take longer than it did.
Applying the Central Dogma
“...to learn and not to do is really not to learn. To know and not to do is really not to know.” Stephen R. Covey
Let's apply some of what we have learned and figure out just what this Central Idea of biology - the realtionship between DNA, RNA and Proteins really is. We'll do this through some giuded questions, and additional evidence using a real world example - the infection of a cell by the HIV virus. In this module, we'll learn about viruses and how the spread, and specifically a bit about HIV and resistance to the virus.