Proteins in the Brain, Body and Nutrition: A Neurological Trifecta! (Day 2 of 2)

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Objective

Students will make and defend the claim that genetic factors influence brain health and development.

Big Idea

In general, genes and proteins have a linear relationship that dictates the general welfare of human body systems.

Introduction

Lesson Background & Justification:

    A Gene is a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring. Genes come in alternate forms called alleles and are picked at random for distribution to the offspring. In genetics, patterns of gene shuffling are studied to better understand the inheritance probabilities and likelihood of one inheriting a genetic defect such as PKU. PKU or Phenylketonuria  is a rare condition in which a baby is born without the ability to properly break down an amino acid called phenylalanine. It is recessive disease that once inherited my cause problems for the cognitive domains of the brain due to toxic levels of a metabolite created when phenylalanine is metabolized. In this lesson, day 2 of a 2 day lesson (Day 1), students will focus on the statistical and genetic aspect of the condition and examine how technological advances aid in our ability to "visualize" this data more readily. 

Prerequisite Knowledge: It is recommended that students be familiar with the structure and function of cells and protein synthesis and PKU basics

Lesson Preparations:

In the effort to prepare for this lesson, I make certain that I have the following items in place: 

a) A class set of Science Take Out: Testing for Genetic Disorders that Causes Brain Damage (1 set per student groups of 2). 

b) Student lab books.

Common Core and NGSS Standards:

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

MS-LS3-1Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

SP2- Developing and using models.  

HS-LS3-3 -Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.

Standards Rationale:

      Modeling is the process by which scientists represent ideas about the natural world to each other, and then collaboratively make changes to these representations over time in response to new evidence and understandings. It is intimately connected to other scientific processes (asking questions, communicating information, etc.) and improves students ability to recall scientific jargon through association. In the classroom, it is important that teachers engage students in modeling practices, to set the foundation of success in a lesson or instructional unit. In this lesson modeling is used in concert with other science practices such as statistical analysis in the classroom to promote students’ reasoning and understanding of core science idea presented.

Reviewing and Refocusing!

10 minutes

Section Sequence:

      In this section of the lesson, students are given an opportunity to review the information learned in the prior lesson (Day 1 of 2) via video viewing and discussion. The idea is to review and to prime students with a mental workflow for a smooth transition into the statistical & technological analysis of the PKU condition.    

a) Slide 6: Read the tasks outlined on the slide and instruct students to complete the listed tasks in Step #1 as presented. After students complete their written portions, solicit for them to share their responses to the question with the group. Limit the number of responses as this activity has the potential to become time consuming depending on the level of detail availed by the student(s) presenting.   

b) Share with students that they will now watch a news segment that chronicles the day in the life a person with condition. Encourage them to consider the similarities and differences in their thoughts to those presented as they view the video.  Note: students should gain a basic review of the condition in the clip as well develop questions regarding the genetics revolving around the condition. Proceed to show the following video:

       

c) Post video, read and facilitate the conversations by utilizing the discussion question prompts presented on the slide.

Extend

60 minutes

Section Sequence: 

     In this section of the lesson, students learn to explain and defend the genetic underpinnings of the PKU condition. The overarching goal is to abridge concepts for students (gene-protein-function-condition) and help them to see the interconnected nature of the life sciences. This activity proceeds as follows: 

a) Slide 7: Read and instruct students to complete the listed tasks (Steps 1-3) on the slide. In the discussion, assure that students understand that gene distribution is the crux of how widespread conditions like PKU are but don't necessarily reflect the numbers of individuals who suffer mental retardation as a result of having the condition. Share that the environmental factors (diet, etc.) mentioned throughout the lab exercises the day prior also play a big role in one's ability to abstain from the problems that are conferred by the genes that he or she inherits. Further add that while the gene inherited and the protein that is produced as a result (a defective PAH enzyme in this case) have a linear relationship, environmental factors like diet can control the degree of impact on the brain and consequently the predicted numbers of those who will suffer mental issues. This is beauty in the gene-protein-function-environmental factors equation! 

b) Read and instruct students to complete the remaining  tasks listed on the slide. Allow for students to utilize board space to demonstrate their methods of discerning the probable outcome of the problem presented in the "Think About it Problem". Make certain that students understand that there are several scenarios that could build out from the problem (all contingent upon the genotype of Anna's mate).

c) Slide 8: Read and instruct students to complete the tasks outlined on the slide. Provide assistance where needed to individual groups to interpret the gel results and discuss the implication of the results (genotypes-phenotypes-lifestyle-neurological consequences). Similarly, provide this context to the class as you facilitate the discussion wherein students share their responses to the question with the class.  

Standards Covered: 

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

MS-LS3-1Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

SP2- Developing and using models.  

HS-LS3-3 -Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.

Pulling it all together!

10 minutes

Section Sequence:

    In this section, the goal is to provide students with a visual and conversation around the gene-protein-function-environmental factor equation and sync the three as interdependent constituents. It is important that students understand and are able to visualize how and why PKU's pathology while a problem in the liver creates problems for the neuron's in the brain and consequently results in processing delays in the brain. This section proceeds as follows: 

a) Slide 9: Read the overarching question as it appears on the slide to the class and share that we are going to take the opportunity make certain that all of the pieces from the 2 day lesson fit together and explain how it leads to potential mental delays in a person with the condition.

b) Start by directing students attention to the perforated boxes at the bottom of the screen. Share that this will be used to develop a sequence of events (genetic, etc.) specific to PKU that will begin with its genetic basis (first box) and culminate to mental retardation (final box). Students will help to develop the flow by feeding information to the instructor. 

c) Ask students: "What amino acid seems to create problems for the patients with PKU?". Draw students attention to the diagram on the screen and use it to clarify the significance of phenylalinine in the brain (precursor for dopamine). Review the significance of dopamine in the brain. Then draw students to the illustration to the right and point out that phenylalinine needs to to be transported to the neurons from the blood in order for dopamine to be produced and perform its intended function. Ask "How might the accumulation of this amino acid create transport problem for the neuron?". After taking responses, share the following science with students from the Pathophysiology Section of this Wikipedia Entry to clarify any misunderstandings.

d) Finally, prompt students throughout the flow chart development process. Ask questions such as "What are genes responsible for producing?, What protein is problematic in this condition?, etc." to aid stimulating student sequencing efforts. This should result in flow chart that progresses as follows:

Genetics (mutation in PAH gene)--> Protein (defective PAH Protein)->Function (loss of ability to metabolize Phe) --> Consequence (Phe accumulates in blood from foods consumed by person) --Effect (Phe competes to cross the LNAAT transporter), etc.

Standards Covered: 

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

MS-LS3-1Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

SP2- Developing and using models.  

HS-LS3-3 -Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.

Evaluate

10 minutes

Section Sequence: 

     In this section of the lesson, my goal is to iterate the connection between genes, the environment and a person's brain health. This activity proceeds as follows: 

a) Slide 4: Read and guide students through the directions and listed tasks on the slide. 

Standards Covered: 

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

MS-LS3-1Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.