In this module:

GOALS:

After completing this module you should be able to:

• List the differences between RNA and DNA
• List the three types of RNA found in cells
• Describe how RNA is synthesized from a DNA template
• Use the genetic code to predict a protein sequence encoded by an mRNA sequence
• Describe how mRNA, tRNA, and ribosomes cooperate in the synthesis of proteins

Introduction: From DNA to Proteins

In the DNA 1 module you learned how genetic information, describing your eye color, blood type, and many other characteristics about you, is stored in the form of DNA and passed accurately from parents to offspring. But how is this information actually used to make blue eyes, an AB blood type, or anything else about you?

Most of your characteristics come about as the result of the set of proteins your body makes. For example, a blue eye color results from the expression of a blue pigment and not a brown pigment in the cells of the iris of your eyes. An AB blood type results from the synthesis of both the A and B antigens by red blood cells in your circulatory system (for more information on the ABO blood type system, see the Carbohydrates module). Thus, at a basic level, the question asked above reduces to asking how the genetic information stored in DNA is used to direct the synthesis of proteins.

In a sense, this module is misnamed, because much more than DNA is involved in answering the question asked above. This module will describe how genetic information stored in DNA is expressed in proteins and introduce you to a new biomolecule found in cells, ribonucleic acid or RNA .