Protein Synthesis Lab, part 2

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Objective

Students will model the process of transcription and translation in order to better understand the process of protein synthesis.

Big Idea

De-coding amino acid sequences correctly is important for life.

Warm-Up

5 minutes

Warm-Up: “What is the relationship between DNA and proteins?”

Remind students to consider what they learned previous lessons, DNA part 1 and RNA part 1.  Allow 2-4 students to respond. Facilitate academic discourse by requiring students to provide to provide rationales for their response and encouraging them to use the academic discourse sentence prompts.   

Without leading students to the correct answer, listen and pay attention to note any misconceptions that arise in the responses from the class. Look for students to correctly state that genetic information is carried in DNA for inheritance of traits and traits are determined by proteins.

Introduce New Material

20 minutes

As a review from the lesson, RNA and rotein synthesis, part 1, ask students to explain what occurs during protein synthesis.  Look for students to identify that proteins are made during this process.  Once it is clear that students know what protein synthesis is, ask them to name and describe each of the steps of protein synthesis.  Expect most students to struggle with this task.  Allow a few students to respond in order to hear their thinking before introducing students to a protein synthesis pneumonic that will help them recall the steps of protein synthesis:

Don’t Make Rumors Talking About People.

Note: This pneumonic device was created by a former student.  I made writing a pneumonic a competition in which students voted by class for the best pneumonic.  Students in all classes then voted for the best “overall” pneumonic device for protein synthesis.

Without giving them any information other than the word, instruct students to focus on the first letter of each word in the sentence and tell them to explain the relationship between the first letter of the word and the steps of protein synthesis. 

For example,ask “What do you think the “d” means when you think about the first step of protein synthesis?”  Allow students to ponder the relationship for 1-2 minutes before asking them guiding questions like, “Where does protein synthesis begin?”  Look for students to identify that the “d” of the word don’t relates to  DNA in the nucleus as the source code used for protein synthesis. 

Prompt students’ thinking by asking leading questions if they need assistance with the thinking process.   After students make the correct connection between the letter of the word and the step of protein synthesis, display the response on a LCD projector so that students will be able to see, as well as hear the reasons for the connection between the letters and protein synthesis.

Inform students that their homework is to create their own pneumonic for the steps of protein synthesis.  By allowing sentences to develop their own sentences, they will be more likely to recall the sentence and remember the steps of the process.


 

Guided Practice

15 minutes

Note: This lab requires a significant amount of preparation.  The Lab instructions will need to be separated into the 6 sets of instructions in advance of the lab. I use different color paper for each set of 6 cards because it makes it easier for me to collect the cards and organize them for the next class. 

Explain that students will work in groups of 4 to model the steps of protein synthesis using color-coded sets of instructions, a pipe cleaner, beads and specific roles that each member of the group will play.  Display an overview of the Protein Synthesis Bead Lab procedures while summarizing the procedures.  Inform students of the 4 roles that must be played and the responsibilities of each role:

  • DNA- responsible for holding the coded instructions
  • mRNA- responsible for translating the DNA code into RNA language
  • tRNA- responsible for going to the raw materials center to gather the beads individually and bringing them back to the ribosome.
  • Ribosome- responsible for assembling the beads onto the pipe cleaner in the order received from the tRNA.

Distribute a  set of instructions to each group of 4 students:

  1. Group # and message card goes to the DNA role
  2. mRNA decoder sheet  goes to the mRNA role
  3. DNA role card goes to the DNA role
  4. mRNA role card goes to the mRNA role
  5. tRNA role card goes to the tRNA role
  6. Ribosome role card goes to the ribosome role 

Lastly, distribute one pipe cleaner and one “Go Get” strip to each group.  Inform students of where to go to find the specific beads needed.   Make sure that a large bowl of beads are available for students to use during the lab process.

Model how to de-code one or two words using the mRNA decoder sheet.  Think aloud as you identify each of the letters that make up the words.  Narrate the reasoning and thought process for identifying each of the letters of in the word.  Use an LCD projector or whiteboard to show your written responses as you narrate.

Independent Practice

20 minutes

Check for understanding by asking at 1-2 students to briefly explain what should occur during the lab.  Once it is clear that students know what to do, release them to conduct the modeling activity. 

Instruct students to keep their protein “hidden” from the other groups as they assemble their protein.  Let students know that they will share their proteins with you and one another at the end of the lab.  All the proteins will match, except one.Do not tell students that one of the proteins will be different, but allow them to make this discovery themselves as the end of the lab.  

Sign off on each group’s product before allowing them to proceed to the question completion.

Distribute a set of 14 questions and instruct students to complete the questions once the group has been signed off for the protein. Allow students to work together to answer the questions, however instruct each student to complete his/her own responses to the questions, using complete sentences.

 If time permits, distribute envelopes labeled, How a Protein is Born.  Instruct students to use the sentence strips that are in the How a Protein is Born envelope to correctly show the steps of protein synthesis. Display the How a Protein is Born instructions on a LCD [projector, as well.  This is a quick and fun way for students to reinforce the concepts they've learned and it also serves as a formative assessment. It may take students a few iterations but they should be able to order the steps of protein synthesis, as shown in the student work.


Close

5 minutes

Allow students to verbally share their responses to these questions:

  • What did you learn?
  • What did you like?
  • What did you dislike?

Listen for specific learning and make it a point to restate and emphasize statements that clearly articulate learning of key points.  Look for students to be able to explain the roles of DNA, mRNA and tRNA now that they've had the opportunity to play those roles.

Also, listen to students’ comments about what they liked and disliked about the lab.  Use their feedback as appropriate when planning upcoming labs.