Ask students to brainstorm traits they have that are passed on from their parents, such as eye color, hair texture, and facial characteristics. Then ask them how these traits are passed on from one generation to the next. The answer is DNA, or deoxyribonucleic acid . Explain that all organisms carry an elaborate blueprint containing the information necessary to develop and maintain life. DNA is found within a person's genes.
Genes are small structures found in chromosomes, structures within the nucleus of cells.
Tell students that DNA works something like the alphabet. Just as the 26 letters of the alphabet can be used to form millions of words for communication, DNA's alphabet can be combined to form codes with more than five billion combinations of G's, A's, T's, and C's. The differences in these combinations result in differences among human beings. The DNA molecule consists of two strands that form a double helix, a spiraling shape much like a twisted ladder. To help students understand how these components fit together to form DNA, have each student make a model of DNA with fishing line, dried pasta, and different-colored pipe cleaners.