Cool Tool: PTC Paper
Topic: Inheritance of Genetic Traits
Grade Level: High school, middle school, late elementary
Contributor: Barbara Berg
School: Fred Hutchinson Cancer Research Center, Seattle, WA
Purpose: To teach students about genetic differences and inherited traits.
Materials: PTC paper (paper impregnated with phenylthiocarbamide) and control paper lacking PTC. Taste Test Strips AP7989 (100 strips/98 cents) and Control Strips AP7990 (100 strips/75 cents) can be ordered from Flinn Scientific (800-452-1261).
Methods: Give students control and PTC strips without telling them what the strips are. Have the class taste the strips and report on their resultsówhether or not they can or canít taste the PTC. Generate discussion about why some people can taste and others canít. The ability to taste is dominant and is controlled by a single gene. Students can also take strips home and test family members. Then they can make pedigrees of the inheritance of this trait and see its dominant pattern of inheritance. There are also other types of strips available for tasting. The PTC activity can also be used in conjunction with scoring other genetic traits, such as tongue-rolling and widowís peak. After tasting the paper, students can remove the taste of PTC by having a drink of water or sucking on a hard candy.
Classroom Use: This is a great opening activity and can be used in both high school and middle school classrooms. Barb has also used this tool successfully in 5th and 6th grade elementary classes.
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last updated 06/15/04