How do Siamese Cats Get Their Color?

Contributor
Amber Todd and Lisa Kenon
Type Category
Instructional Materials
Types
Lesson/Lesson Plan , Activity
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

This resource is an article from the January 2016 issue of The Science Teacher.  The unit focuses on an essential question:  How do Siamese cats develop their coloration?  Students develop explanations by making connections among genes, proteins, and traits.  The unit is designed to be implemented over six or seven instructional days. However, each activity can be used as a stand-alone instructional strategy.  During the instructional cycle, students develop an initial model to explain how Siamese cats get their coat coloration, learn about enzyme structure and function, use a computer model to see how proteins interact, experiment with Jell-O to see enzymes in action, learn about molecular motor proteins to see how structure relates to function, revise their model of coat coloration, and experiment with precursors of melanin to see how proteins can lead to observable traits.  The unit is designed to help teachers extend the central dogma concept beyond the idea that proteins are the final products in the process.  The unit provides opportunities for students to develop a conceptual understanding that proteins are important in cellular functions as well as trait-producing mechanisms. The article includes a teacher guide which describes how each activity is aligned to the Next Generation Science Standards.   Unit handouts for students and the teacher guide  are found on the NSTA website at www.nsta.org/highschool/connections.aspx.
 

Intended Audience

Educator and learner
Educational Level
  • Grade 12
  • Grade 11
  • Grade 10
  • Grade 9
Language
English
Access Restrictions

Available by subscription - The right to view and/or download material, often for a set period of time, by way of a financial agreement between rights holders and authorized users.

Performance Expectations

HS-LS3-1 Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.

Clarification Statement: none

Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The Siamese Cats unit is designed to be taught before the central dogma, replication, transcription, and translation and after instruction on protein structure and functions and cell structure, functions, and specialization. The unit is centered on one essential question and students complete a series of differentiated activities to develop a solution. An NSTA publication Hard -to-Teach Biology Concepts (https://www.nsta.org/store/product_detail.aspx?id=10.2505/978193 8946486) can provide additional instructional strategies to teachers in developing lessons on this content.

HS-LS1-1 Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

Clarification Statement: none

Assessment Boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The article suggests that this unit should be taught prior to DNA instruction and the central dogma to help students understand the overall purpose of proteins instead of seeing protein production as the final step of the central dogma. This learning progression provides students with an opportunity to make connections between DNA and genes as the instruction for making proteins which are responsible for all cellular activities include trait-production mechanisms. If there is a substantial time lapse between the Siamese cat unit and DNA instruction, teachers will need to review protein structure and function. This review can be done with paper models, videos, and computer simulations. HHMI’s Gene Expression Teacher’s Guide can provide additional support in planning instruction: (http://www.hhmi.org/biointeractive/teacher-guide-gene-expression).

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
On Day 4, students use a hands-on activity to explain why certain fruit juices prevent Jell-O from setting. After viewing short videos on Day 5, students explain how a change in cardiac myosin protein affects an observable trait such as an enlarged heart. This content is very biochemistry-rich and teachers need to provide an extensive review of this content. On Day 6, students use a hands-on activity to explain how catechol oxidase produces brown coloration in potatoes or apples. Teachers need to make sure students are following safe classroom procedures. Catechol is a poison and students need to use extreme care in handling the substance. Teachers can use apple or lemon juice as an alternative to catechol. Teachers’ prep for these substitutions can be found in the online lesson plan. Teachers need to guide students in making connections between the classroom activities and the content and use these connections to revisit and revise their initial models on Siamese cat model coloration.

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
On Day 1, students are presented with a scenario involving Siamese cats. They are asked to draw an initial model of how Siamese cats get their color. At various points during and after completion of the unit, students are asked to use what they learn to revise their initial model. As a culminating activity, teachers can lead a whole-class reflective discussion about what was learned during the instructional unit.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The Siamese Cats unit is designed to be taught before the central dogma, replication, transcription, and translation and after instruction on protein structure and functions and cell structure, functions, and specialization. Prior to starting the unit, teachers can use an anticipation/reaction guide to identify students’ misconceptions about the relationship among DNA, RNA, and proteins. Examples of of anticipation guides can be found at www.gyst.org6thGrdCur/documents/s6e2/c/es_1.pdf or www.ncrel.org/sdr/areas/issues/students/learning/lr1anti.htm. Teachers can use the responses to guide a preliminary whole-class discussion on the relationship.

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
By teaching this unit before instruction on DNA introduction, students should be able to make connections and explain how the structure of DNA is transcribed to RNA and translated to proteins. Proteins are used to direct cellular functions including trait-production mechanisms. Teachers can add additional paper and pencil models, computer simulations, and videos to their instruction if students need more support in making connections among genes, chromosomes, and DNA. The reading homework assignments listed in the article will provide additional support if needed.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Throughout the unit, students learn how structure relates to function using paper models, computer animations, video, hands-on experiment, and reading assignments before developing their final model to answer the essential question. This unit is very content-rich and teachers may need to modify some of the activities to meet their students’ needs. Also, some students may need additional vocabulary development support to understand the content needed to complete some of the activities. Teachers can use graphic organizers, Foldables (http://www.dinah.com/index.php), and word walls as vocabulary development strategies. NSTA offers many publications that can be used to support vocabulary instruction (http://www.nsta.org/search.aspx?cx=000595497003495966486:w02godv4_pe&cof=FORID:11&q=vocabulary%20development).

Resource Quality

  • Alignment to the Dimensions of the NGSS: Several activities in this unit support the practice of developing and using models. Students are asked to develop a model and construct explanations of cat coloration through a series of activities that include using Jell-O to explain how enzymes can become denatured. Students watch a video and using computer simulations and models to explain how a change to a myosin protein can affect an observable trait. Students experiment with catechol oxidase to develop an explanation of how temperature changes affect enzyme function. This unit supports the Disciplinary Core Ideas by asking students to explore how heat and acid denatures catechol oxidase to render it nonfunctional and reading about a mutation in Siamese cats. The unit provides multiple opportunities to support the Crosscutting Concept of structure and function via paper models, readings, hands-on activities, and computer animations, ending in an explanatory model of how heat-sensitive structure of an enzyme in Siamese cats lead to their coat coloration pattern in cats.

  • Instructional Supports: The opening activity in this unit engages students with a scientificly accurate scenario using Siamese cats. The unit provides students with opportunities to explore multiple practices using different engaging activities. Students use both paper and computer models, experiment with Jell-O and fruit juices, view computer animations, and explore how catechol oxidase produces brown coloration. The article provides a lesson plan overview that includes learning objectives, warm-up activities, main activities, closing assessments, and homework for each day of the unit. Examples of student work and a table of Next Generation Science Standards connections are also provided in the article. A very detailed lesson plan and students’ handouts are provided on the web. The unit provides many differentiated activities that will support students in developing models and explanations to answer the essential question.

  • Monitoring Student Progress: This unit provides many opportunities to monitor students’ learning during the entire learning process. The detailed student guide provides thought-provoking questions after each activity. The teacher’s guide provides sample questions that teachers can use at the beginning of each activity to engage students and at the end to assess student learning. Teachers can develop additional questions to use as daily class opening questions (bell ringers) or exit tickets.

  • Quality of Technological Interactivity: This is not an interactive technology-based resource. However, it does provide links for videos that are used during the unit.