When Things Go Wrong: Genetic Mutations

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Objective

SWBAT identify different types of genetic mutations and explain the specific mechanism that caused the mutation by examining the errors that have occurred during DNA replication.

Big Idea

In the 3 billion base pairs in our genome, what happens when there is an error in the DNA. Students will examine the cause and effect of various genetic mutations.

Video Introduction - Identifying Mutations

1 minutes

This video clip serves as an introduction to the lesson and provides an explanation of the NGSS that are addressed throughout the activities.

This lesson will serve as an introduction for the next lesson where students will be selecting and researching genetic disorders that occur as a result of specific genetic mutations.

Hook - Misspelled DNA

5 minutes

As an introduction to the genetic mutations, students will read the original phrase below and try to decode the three example phrases to identify the change that has been made to cause the error in the letter sequence.  

Original Phrase:  The fat man sat on the cat.

Altered Phrases:

  1. The atm ans ato nth eca - deletion mutation
  2. TThefatmansa ton the cat - insertion mutation
  3. The fat mma nsa ton the cat - duplication mutation

 

Student Reflection Questions:

#1. Identify the change in the letter sequence that have been made in each of the altered phrase examples.

#2. Do any of the altered phrases have the same meaning as the original phrase?

#3. How many letters were changed (added, deleted, or duplicated) in each of the phrases?

#4. How does this practice problem relate to DNA and our study of genetics?

The students will participate in a whole-class discussion to review the answers to these reflection questions.  The responses to these reflections questions allow the teacher to gauge the level of student understanding which will guide the depth of details that can be accomplished in today's lesson.  If the students do not understand these simple review questions then the teacher needs to scaffold instruction to build student comprehension.

Direct Instruction - What Happens When Things Go Wrong?

20 minutes

Students will record information from the Genetic Disorders Lecture Notes to be used as a reference later in this lesson and during the Genetic Disorder Research Project.  This set of lecture notes goes into a detailed description of the five types of genetic mutations, as well as possible genetic disorders that occur in our population.

  1. Deletion
  2. Insertion
  3. Duplication
  4. Insertion
  5. Nondisjunction 

Students are expected to record the information in the lecture notes to reinforce their learning of the content.  The teacher will also post the lecture notes on the class website so students can access the information at a later date if necessary.  Students are also encouraged to participate in the lecture by asking questions and offering relevant real life examples.  Students love to show how much they know and this is a great time to allow your students to shine!

 

Independent Practice - Identifying Types of Mutations

10 minutes

Students will complete the Gene Mutations Practice Worksheet to reinforce their understanding of the five main types of genetic mutations.  This worksheet uses simple letter "genes" to demonstrate deletion, insertion, duplication, inversion, and nondisjunction genetic mutations.  By using simple A,B,C's students are able to conceptualize what is happening at the DNA level when a mutation has occurred.  The students are encouraged to use their Genetic Mutations Lecture Notes and textbooks as resources to guide their progress through this activity.  My Biology class currently uses the 2007 Prentice Hall Biology textbook with the dragonfly on the front cover.  This book provides easy to understand content with engaging illustrations to support student learning.

The students will pair-share their responses and provide a verbal explanation their rationale for identifying the specific genetic mutations for each example.

After the pair-share, the teacher will ask for volunteer groups to share their answers and the class will be able to provide feedback that supports or questions the answers given by the volunteer groups.

Gene Mutation Student Work - This sample demonstrates that the student is able to identify where the mutation has occurred but sometimes have a difficult time either determining the type of mutation or exactly which base pairs have been impacted.  This student has a strong understanding of the content and really enjoyed the activity.

Close - How Does A Mutation Change The Protein?

10 minutes

In an effort to tie in the students' understanding of protein synthesis from a previous lesson, the closing activity will relate how the mutations in DNA will effect the outcome of which amino acid is created.  Students will follow the steps below to complete the Practice Worksheet:

Step One: Students will locate the original sequence located in Column C of the data table.  

Step Two: Students will transcribe the original DNA sequence into a mRNA sequence using the universal genetic code diagram from their textbook and record the results in Column B.

Step Three: Students will translate the mRNA sequence into the corresponding amino acids using the universal code diagram from their textbook  and record the results in Column A.

Step Four: Students will go back to Column C to locate the original DNA sequence and circle bases #3-8.

Step Five: Students will invert bases #3-8 to create a mutated DNA sequence and record the results in Column D.

Step Six: Students will transcribe the mutated DNA sequence into a mutated mRNA sequence using the universal genetic code diagram from their textbook and record the results in Column E.

Step Seven: Students will translate the mutated mRNA sequence into the corresponding amino acids using the universal code diagram from their textbook  and record the results in Column F.

Step Eight: Students will examine the data table and respond to the conclusion questions at the bottom of the activity.

If the students run out of time to complete this activity in class, they will finish this practice activity as homework.  

Students will also need to respond to how the mutation affects the protein that is created, thus impacting the organism.

The video clip below shows the teacher guiding the students through one example from the Practice Worksheet and provide a detailed explanation on how to complete the complicated data table.

Mutations and Proteins Activity- Student Work# 1: This student artifact demonstrates a basic understanding of the concept on how a mutation in DNA will effect mRNA which will have a high potential of changing the resulting amino acid.  This student would benefit from taking more time to explain how the genetic mutation effects the organism and examining the process in more detail.  

Mutation and Proteins Activity - Student Work#2:  This student's understanding is exemplary and goes into sufficient detail to explain how the genetic mutation has the potential to alter the amino acid and protein that are created.