Chemistry
Chemistry is the basis for modern pharmaceutical research.
Chemistry is the study of how atoms react with each other.
This picture is of something called the periodic table of elements. Each box in this picture represents a different “element.”
An element is the smallest unit of any physical thing that cannot be broken down further without a nuclear reaction, or in other words, an element is a particular type of atom. Nuclear reactions do not happen naturally on earth, so it is usually easy to determine which units are elements. All atoms are single units of some element.
The periodic table arranges elements by their properties. The elements of any column of this table have similar properties, and from left to right and top to bottom the elements get heavier. The similar properties which are seen for atoms of different weights down any given column is what makes the table “periodic,” as in, “periodically, the same properties reappear in other elements.”
When two or more atoms react, that means that they connect to or disconnect from each other. A set of two or more atoms which are connected are called a “molecule.” Different molecules always have different properties, and molecules have properties which are not obviously related to the atoms from which they are composed.
Some common examples of molecules are H2O, which is two hydrogen atoms connected to an oxygen atom to make a water molecule. Another example is C2H6O, which is two carbon molecules, six hydrogen molecules, and one oxygen molecule, all combined to make ethanol, or drinking alcohol.
There is a special class of molecules called organic molecules. Organic molecules are the molecules of life – they are almost always only made by living things. Organic molecules are composed almost entirely from four elements – carbon, oxygen, hydrogen, and nitrogen.
Almost every aspect of disease research involves molecules, but the word “molecule” is not often used. Because there are so many types of molecules, they are usually further classified according to their function. The most commonly studied molecule is the protein.
Living things are made mostly of water, but the trait which makes each kind of living thing unique is its proteins. Proteins are the machines inside every living thing which carry out all the functions which characterize life.
Proteins are incredibly complicated and huge clusters of molecules, most of them being composed of tens of thousands of atoms. Inside every living thing, proteins are continually making other proteins by means of a set of instructions called “DNA.” DNA is a set of chemical instructions written in a language which codes for small molecules called “amino acids.” All proteins are composed almost entirely of amino acids, so it is legitimate to say that DNA is a set of plans to make proteins.
the Scale of the Microscopic World
The biology section which follows this one will explain the terms which are used to describe life forms, but understanding how to do research on microscopic things is still a problem associated with chemistry. The most important thing to know is the relative sizes of things. Atoms larger molecules, and a protein is an example of a large molecule. Proteins make other things, such as complex cells, bacteria, and viruses. Consider this size representation:
It is vital to basic understanding of modern research to understand the differences between these things, and the most obvious difference is size. Complex cells, such as fundamental units which make all plants and animals, are 0.001 – 0.0001 meter in diameter, or between one millimeter and one-tenth of a millimeter in length. Bacteria are smaller, being 1 to ten micrometers in diameter, or 0.00001 – 0.000001 (10-5 – 10-6) meters in length.
It would be okay to think that many complex cells, such as human body cells, are 1000 times larger than most bacterial cells. Viruses, in turn, are one-hundredth the size of bacteria. Proteins, which are coded by DNA and therefore make up all life, are about a tenth the size of many viruses. A virus is not much more than a protein, and in turn, proteins can be just 100 times the size of atoms.