Determine the number of possible genetic codes. Class members are challenged to determine the number of possibilities of a genetic code that is 20 bases long. They continue to explore the average lengths of broken RNA molecules.

Try this quick, five question comprehension check over DNA, RNA, and protein. Each question has a hint available, as well as a self-checking feature.

Try this quiz about RNA and the origin of life.

Students have the opportunity to work through a problem set over Eukaryotic genes. Correct answers are reinforced with a brief explanation. Incorrect answers are linked to tutorials to help solve the problem.

Read a passage about early experiments on the genetic code and answer the follow-up questions.

Read this passage and study the graphics to complete a five-question quiz related to the viral life cycle and antiretroviral therapies for HIV/AIDS.

Take this 32 question quiz on control of gene expression. The quiz is multiple choice.