5. Secret Codes - Lesson Plan
- Ask the students, “If you were a spy, how would you write a message to headquarters in a way that if the enemy intercepted it, they would not know what the message said?” Students will instantly respond with using a secret code. Ask for clarification of what a secret code is and how it is used.
- Give students the handout. Briefly discuss what Morse code is and how it is used.
- Have students try to decode the message at the bottom of the page. The secret message says, “I love learning about genetics!” Make up your own messages for students to decode as additional practice.
- Next, have students make up their own secret code by writing a different symbol (letter, number, picture) next to each letter of the alphabet on the right hand side of the page. Students can use their personal code to write a secret message to a friend on the bottom of the page.
- Collect the handouts when students are done, shuffle them, and redistribute them so students can practice decoding someone else’s message.
- Now that students are fluent with coding and decoding messages, introduce how DNA is a code for making proteins. Describe protein structure. Outline the 2 basic steps of the protein synthesis process: 1) DNA is transcribed into messenger RNA and 2) ribosome reads the RNA and assembles a chain of amino acids using the RNA codons.
- Have students flip their handouts over and look at the genetic code. Go over the examples, showing how the DNA codes for a protein message with a two step decoding process. First translate the top line of the DNA into RNA. Then use the table to identify the sequence of amino acids that matches each 3 nucleotide codon. The secret message at the bottom of the page says, “I like math”.
- Give students additional DNA codes to solve. See the Assessment section for ideas or create your own. Since there are only 20 amino acids, some letters cannot be used (B, J, O, U, X, Z).
- Optional: Show students the video of transcription and translation from the DNA Interactive website (click on the “Code” tab, then click the “Reading the Code” tab and finally click the “Putting it Together” tab.)
Submitted by irene on Mon, 2006-07-10 20:06