Ptc Genetics Lab Student Worksheet (Page 3 of 10) in pdf

Ptc Genetics Lab Student Worksheet Page 3

PTC

PTC sensitivity is often used as an example of a simple Mendelian inheritance (for more information refer to

Appendix A). Below is an example of simple Mendelian inheritance.

Mom has both “tasting” and “non-

Dad has both “tasting” and “non-

tasting” receptors. She can taste

tasting” receptors. He can taste

PTC.

PTC

Receptor

Child 1 has all “tasting” receptors. He can

Child 3 has both “tasting” and “non-tasting”

taste PTC. There is a 25% chance of this

receptors. He can taste PTC. There is a 50%

outcome given the parental genotype.

chance of this outcome given the parental

genotype

Child 2 has all “non-tasting” receptors. She cannot taste PTC.

There is a 25% chance of this outcome given the parental genotype

Scenario

Jillian is a student at Cactus High School in Peoria. Her class learned about PTC tasting when her class learned

about inherited genetic traits. As it turned out, she was not a taster. Jillian decided to get some PTC paper and

have her family do the taste test, and draw a family tree based on the tasting data. Surprisingly, everyone in her

family is a taster, her mother, her father, both her brothers, and even her grandparents, aunts and uncles. Jillian

was quite perplexed. How is it possible that Jillian cannot taste PTC when everyone else in her family can taste?

Based on what you know about genetics come up with a hypothesis and how you could test this hypothesis.

Hypothesis

Prelab Part I (

Optional Activity)

Are you a PTC taster? If so, what does PTC taste like?

2. How many people in your class are tasters? How many people in your class are non-tasters?

3. Why do you think some people can taste the PTC and others can’t?

Ptc Genetics Lab Student Worksheet Page 3