Basics of Molecular Biology. Martin Tompa. Department of Computer Science and Engineering. Department of Genome Sciences. University of Washington …

Martin Tompa
Department of Computer Science and Engineering
Department of Genome Sciences
University of Washington
Seattle, WA 98195-2350
U.S.A.

July 6, 2003
Updated December 18, 2009

We begin with a review of the basic molecules responsible for the functioning of all organisms’ cells. Much of
the material here comes from the introductory textbooks by Drlica [4], Lewin [7], and Watson et al. [10]. Good short
primers have been written by Hunter [6] and Br¯ zma et al. [2].

What sorts of molecules perform the required functions of the cells of organisms? Cells have a basic tension in the
roles they need those molecules to ful?ll:

1. The molecules must perform the wide variety of chemical reactions necessary for life. To perform these reactions, cells need diverse three-dimensional structures of interacting molecules.

2. The molecules must pass on the instructions for creating their constituent components to their descendents. For this purpose, a simple one-dimensional information storage medium is the most effective.

We will see that proteins provide the three-dimensional diversity required by the ?rst role, and DNA provides the one-dimensional information storage required by the second. Another cellular molecule, RNA, is an intermediary between DNA and proteins, and plays some of each of these two roles.

Proteins

Proteins have a variety of roles that they must ful?ll:
1. They are the enzymes that rearrange chemical bonds.
2. They carry signals to and from the outside of the cell, and within the cell.
3. They transport small molecules.
4. They form many of the cellular structures.
5. They regulate cell processes, turning them on and off and controlling their rates.

This variety of roles is accomplished by the variety of proteins, which collectively can assume a variety of three dimensional shapes.

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