Download PTC Unit Plan

ARISE
Teaching Unit Template
Title of Unit/Module
To taste or not to taste, that is the question!:
PTC Tasting Lab – Inquiry Activity,
Developed by:
ARISE Planning Team
Appropriate Course(s)/Grade(s):
Biology 1B, Biology II, Genetics (9 – 12)
Brief Summary of the Unit:
In this unit students will learn about genetic variation and techniques scientists
use to manipulate and study DNA. They will be given the opportunity to use
scientific equipment pertinent to this particular lab. The opening activity will
engender student questions with regard to why some people taste PTC and others
do not. Students will then analyze sets of data comparing taster DNA and
nontaster with nonhuman primates. As part of the unit students will be encouraged
to come up with their own testable questions, collect data and look for patterns in
their ability to taste using a variety of taste papers. To enhance understanding
students will engage in a restriction enzyme lab, which demonstrates the power of
restriction enzymes as an investigative tool.
Grade Span Expectations
LS1 (9-11) – 2a, 2b, 2c FAF+POC -2
LS3 (9-11) 6a NOS, 7a, and 7b
LS3 (9-11) 8a INQ – FAF – POC
Content Standards from Benchmarks
for Science Literacy
Some new gene combinations make little
difference, some can produce organisms
with new and perhaps enhanced capabilities,
and some can be deleterious. 5B/H1
Genes are segments of DNA molecules.
Inserting, deleting, or substituting
segments of DNA molecules can alter genes.
An altered gene may be passed on to every
cell that develops from it. The resulting
features may help, harm, or have little or no
effect on the offspring's success in its
environment. 5B/H4
Prior Knowledge:
This activity requires an understanding of the structure of DNA, the processes of
transcription and translation, which lead to the production of proteins and
ultimately manifest themselves as traits.
Also, students must have an understanding of elementary laboratory safety skills
of procedures.
DESIRED RESULTS
What essential questions will be considered?
1. Why can some people taste PTC and others not?
2. Is there an advantage / disadvantage to be a taster or nontaster?
3. How do scientists collect, compare and analyze segments of DNA?
4. How can a gene make it possible for us to taste?
5. What is the relationship between traits and genes?
Students will know:
1. The reason why some people can taste
PTC and some people cannot.
2. The location of the gene and the
amino acid structure.
3. The relationship between genotype
and phenotype.
4. The consequences of mutations, some
mutations are harmful, some are
helpful, and some are neither.
5. How to accurately interpret the
results of a gel electrophoresis.
Students will be able to:
1. Follow scientific protocols.
2. Generate and analyze sets of data
as it relates to the PTC unit.
3. To successfully manipulate scientific
tools such as micropipette and gel
electrophoresis equipment.
4. Predict genotype based on
electrophoresis data and compare
with phenotype.
ASSESSMENT
Performance tasks
What will the students produce to provide evidence of understandings and
skills learned?
Periodic reflective / notebook journal for identifying student questions and
reflecting on activities conducted during class.
Demonstrate proficiency in scientific measuring with regard to use in the PTC lab.
Interpret electrophoresis data.
Student will develop and orally Present electrophoresis experimental data, followed
by student / teacher debriefing.
Students will isolate DNA, set up PCR reaction and interpret results.
Lab skills/practical
Plan skit of how cell responds to PTC, present skits
Other evidence of learning (quizzes, tests, prompts, observations, lab reports,
work samples, etc.)
Formative:
Teacher led discussion based on student generated questions and shared journal
entries.
Periodic quizzes
Guided Questions centered around scientific data based on essential questions.
Concept Map
Exit Tickets:
Teacher generated questions or the generic
 What did you learn?
 What are you confused about?
 What do you need to know?
Summative:
Individual Unit Test
Poster/Presentation (One PowerPoint slide) of student generated experimental
questions/analysis/results
Each Small Group Questions
Pictorial Quiz on Technique and reading the gels.
Oral Presentation / final group presentation
Student Self-assessment and Reflection:
Journals for individual reflections
What makes a testable question?
How have the questions you asked changed as we moved through this unit?
LEARNING EXPERIENCES AND INSTRUCTION
Inquiry Features Included
Formulating Questions & Hypothesizing
1, 1a (DOK 3)
Conducting Investigations
7 (DOK 1)
8 (DOK 2)
Developing and Evaluating Explanations
12 (DOK 3)
Instructional Sequence/Calendar – This unit is designed to take 8 (66) minute
class periods. Upon completion of the unit, students will be given a prompt that will
require them to complete a reflection essay.
An alternative assessment would be an end of unit test.
DAY 1: Introduction to the genetics of taste
1. Pose the questions: (either individually or in small groups)
1. Why do you think people prefer one food over another?
2. How do we taste?
3. What do we taste?
4. Why do we taste?
2. Inquiry Activity: Why can some people taste PTC and others cannot?
a. Hook: Have students attempt to taste PTC paper.
b. Record data on the board to be analyzed later (strong, weak, nontaster)
c. Review prior knowledge (homozygous, heterozygous, transcription,
translation, amino acids)
d. Review inquiry activity background information.
e. Complete understanding check & review.
f. Inquiry questions: Example: Is there a connection between the foods we like
and whether we are a taster and a non-taster?
Homework: Compare the genotype of nonhuman primates.
DAY 2: PCR Dry Lab
1. Journal: reflection question from day 1
2. Review homework
3. Discuss PCR lab procedure
4. Use video animation for demonstration of PCR:
http://learn.genetics.utah.edu/units/biotech/pcr/
5. Engagement: working in small groups students will use simulated restriction
enzymes to cut DNA into pieces.
6. Post data on the wall / blackboard
DAY 3: Micropipetting
1. Journal entry: Reflection on PCR dry lab
2. Discuss the use of micropipetting in DNA analysis
3. Modeling the use of micropipettes
4. Complete laboratory activity on Micropipetting
5. Run gel electrophoresis with food coloring
6. Discuss results and connect to DNA electrophoresis
DAY 4, 5, 6: PCR Lab: According to protocol
Day 7: Follow up Activity: Is there a relationship between tasting PTC and
other substances.
1. Collection of data (Thiourea, Sodium Benzoate)
2. Organize data to compare with the ability to taste PTC.
3. Interpret Data and answer guided questions
4. Pedigree analysis
Day
1.
2.
3.
4.
8: Journal: revisit lab
Why do some people taste PTC?
What makes a taster different from a nontaster?
How do you explain a weak versus strong taster?
Are there any patterns in the types of things tasters and non-tasters can
taste?
5. Is it “bad” to be a taster or a nontaster?
6. How do we compare the DNA of tasters and non-tasters?
7. How can we compare genes from different species?
Wrap up of Unit: Essay / or end of unit test
Justify the statement: “The ability to taste is inherited”
Technology and Other Resources Needed
Projector / computer
PTC, Thiorea, Sodium benzoate tasting paper
Digital camera
Micropipettes and tips
Thermalcycler
Centrifuge
PCR reagents
Gel electrophoresis