Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
Students will be able to explain:
- the possible effects of mutation on an organism's phenotype.
- how mutations in DNA alter the formation of an amino acid sequence.
Prior Knowledge: What prior knowledge should students have for this lesson?
The students should have prior knowledge of DNA transcription and translation. In using the Mutations Worksheet, the students are reviewing the transcription and translation of a DNA sequence while discussing the mutations of the sequence. When the class translates the RNA sequence to the amino acid sequence, the student will recognize any errors they might have.
Guiding Questions: What are the guiding questions for this lesson?
- Do DNA mutations always alter the DNA sequence? Do they always alter the amino acid sequence?
- What difference between DNA and RNA base pairs do you need to know in order to transcribe the sequence correctly?
- Do DNA mutations lead to diversity?
- Are DNA mutations harmful?
Teaching Phase: How will the teacher present the concept or skill to students?
The teacher may want to review the "Prior Knowledge" before teaching about genetic mutations. The teacher will present the concept as part of translating the given RNA sequences to amino acid sequences. One may wish to ask students what they think might happen if a mutation occurs (in reference to the RNA, amino acids, and phenotype it may alter). Referencing the Mutations Worksheet (see link below), the teacher will describe the different types of mutations and how they affect the DNA sequence (and therefore the amino acid sequence). The teacher may also want to show the video from Boseman Science.
The Mutations Worksheet is from Franklin County Public Schools in Kentucky. An Mutations Worksheet Key is available via the Georgetown Independent School District in Texas. Note: Sickle cell anemia is misspelled on page 2 in the first paragraph of that portion of the worksheet. The teacher should correct the typo before printing.
Guided Practice: What activities or exercises will the students complete with teacher guidance?
The students will transcribe the DNA sequences on the mutations worksheet (see Teaching Phase). The teacher will then guide the students in translating the RNA sequences (determined by the students) to the amino acid sequence. The guidance will allow the students to find any errors in transcription and review translation of an RNA sequence. Have students discuss what they noticed changed by the different mutations.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the lesson?
Students will complete a color by number activity to visually represent a mutation in a DNA sequence. The attached DNAsequence.pptx provides an example of a completed color by number pair. The used in this example is by DeviantArt user Quaddles-Roost and is freely available.
- Each student will be given a DNA sequence and two copies of one color-by-number picture. See the resources section for suggested websites to look for pictures.
- The students will translate and transcribe the DNA sequence in order to obtain an Amino Acid sequence. The students will also be given a list of the Amino Acids (each assigned before class with a different color). The number assigned to the Amino Acids will be based on the order they are in the student's sequence (the first Amino Acid is 1, the second is 2, etc.) after the start codon. If the first amino acid is alanine, then all parts of the picture with a 1 will be colored blue.
- The students will then color in the first picture based on their sequence and the color list. The same color list may be used for all students in order to make it easier for the teacher and allow help from peers.
- After each student has finished coloring his or her first picture, they will be a given a mutated version of their DNA sequence. The students will repeat what they did with the first DNA sequence to see if the mutation has altered the picture.
- The student will compare to two pictures to determine if there are any differences between them. If the mutation has altered the amino acid sequence, then the second picture will differ in some way than the first. If there is no change, then the mutation did not alter the final product (as may happen with mutations).
Note: The first slides in the PowerPoint were designed to make it easier to see the numbering of the picture to be colored; each student only needs 2 copies in order to complete the assignment. The pictures are numbered instead of using the amino acids present because a mutation may alter not only what amino acids are in the sequence, but also how often an amino acid occurs in a sequence or in what order the amino acids are arranged. Any of those changes in the amino acid sequence will alter the protein structure (and therefore should alter the picture being colored).
The teacher should walk around the room during this process to ensure accuracy and the translation and transcription. The students should show their amino acid sequence to the teacher before coloring in the picture to ensure a proper comparison between the two pictures at the end. It will be best to have several students with each picture/DNA sequence combinations (with different mutations) so the students see the how different types or locations of DNA mutations affect gene expression.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
The teacher will have the students present their pictures (it is best to use a document camera to show the two different DNA sequences at the same time as the colored pictures). The students should compare their pictures to the other students who had the same original DNA sequence to compare how the different mutations altered the pictures in different ways. The teacher will also have the students explain where the change in the DNA, RNA, and Amino Acid sequence occurred. After seeing the different pictures presented by the class, the students should have a better understanding of the fact that DNA mutations may alter the amino acid sequence substantially, very little, or cause no change. This will allow the students to understand that the phenotype of an organism will not always change when there is a DNA mutation (the colored pictures being an example of a phenotypic change as well as making the change in the Amino Acid sequence more obvious). The teacher may wish to have a further discussion about DNA mutations may have a positive or negative affect on the lifestyle if the animal. If it benefits the animal and is passed to its offspring, it may continue spread throughout the species (and possibly lead to a new species).
The attached rubric may be used to evaluate student work on this activity.
The teacher will determine if the student has reached the learning targets if he/she has accurately colored in the provided pictures. The teacher will also asses student knowledge based on the student's presentation of his or her results and the description of the affect the mutation had on both the amino acid sequence and the picture.
Each student's mRNA and amino acid sequence should be assessed prior to the coloring to ensure the students are correctly determining the amino acid sequence. The teacher should ask the students if they see any differences between the two sequences they are working on individually to evaluate understanding at this point.
Feedback to Students
The teacher will be walking around the room to look at the work of each student. The teacher will provide immediate feedback as the students are working on their independent work. The teacher should provide feedback on their amino acid sequences prior to the coloring in order to allow a more accurate comparison of the two final pictures.