For this assignment, you will first make a model of a DNA strand using pop beads. This DNA strand
codes for a protein, which determines a trait in an organism. Next, you will change the base sequence of
your model in three ways to show how mutations occur. Then, you will compare the base sequence of the
mutated models to sequences on a key provided by your teacher to find out whether the mutated strand
creates a protein that is beneficial, harmful, or neutral. Finally, you will answer some questions to
summarize what you have done in this project. The Student Worksheet on the last few pages of this
document will help you complete your assignment.
Background Information
DNA is the genetic material passed from parent to offspring. It is an important molecule because it carries
instructions used for producing proteins. These proteins determine how an organism looks and functions.
DNA is a double-helix molecule. The two sides of the molecule, its backbone, are made of sugar
molecules and phosphate molecules. These sides are connected by rungs made of nitrogen bases. The
nitrogen bases of DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).
A gene is a segment of DNA that codes for a specific trait. The sequence of nitrogen bases in a gene is
copied from DNA into a strand of RNA in the nucleus of a cell. The RNA then moves out of the nucleus to
the ribosome. The ribosome uses the information that RNA copies from DNA to produce proteins that
have specific shapes and functions. The shapes of proteins help them perform their job. If the shape of
the protein is changed, the protein may not be able to perform its function. A mutation, which is a
permanent change in the DNA sequence in a gene, may change the shape of the protein it codes for.
Types of mutations include substitution, insertion, and deletion. The effects of mutations on organisms
may be beneficial, harmful, or neutral.