Mini-Lesson Plan Guide for Science

Date(s): Subject: The Genetic Code Grade Level: 9-12

Lesson Planning
Benchmark/Standard: What is the next benchmark on my course curriculum guide or FCIM calendar?
SC.912.L.16.9: Explain how and why the genetic code is universal and is common to almost all organisms.
Essential Questions: How will I reword the benchmark into specific questions using student friendly terms?
•  What is the universal genetic code?
•  Why do almost all organisms have the same genetic code?
Materials/Resources: What do I have or need to teach this lesson?
Projector “Using the Genetic Code Table” handout
Computer w/ internet access “Circular Genetic Code Table” handout (or use as projection)
Lesson Agenda: How will I deliver this lesson to help my students answer the essential questions?
Day One: Explicit Instruction
Day Two: Modeled Instruction
Day Three: Guided Instruction
Day Four: Independent Instruction
Day Five: Quiz
Lesson Delivery
Explicit Instruction: How will I focus my students on what they need to learn? Which important vocabulary will I introduce/review?
·  Teacher will hook students with video clip “Immortal Thread”
http://www.pbs.org/wgbh/evolution/library/04/4/quicktime/l_044_02_56.html
Ask: What does this indicate about the evolutionary relationship of humans and yeasts? Explain.
·  Teacher will use powerpoint to explain the universal genetic code and its origins
Modeled Instruction: How will I show my students what they are expected to do to answer the essential question?
·  Discuss with the class what they think is meant by the genetic code: Be sure that students understand that the genetic code refers not to DNA itself, but to the relationship and processes that allow a specific DNA sequence to determine a specific amino acid sequence. Remind them also that these amino acid sequences form proteins and that proteins influence the collection of traits an organism has.
·  Teacher will use interactive model of “Explore a Stretch of Code” to help explain the genetic code used within a single human chromosome http://www.pbs.org/wgbh/nova/genome/explore_wave.html
1.  Click on “start codon”, read explanation 2. Click on “ancient code”, read explanation
3. Click on “sites of variation”, read explanation 4. Ask students: Where is there evidence for our evolution in our DNA code?
Guided Practice: How will I help my students practice answering the essential question?
·  Provide each student with a copy of the “Using the Genetic Code Table”. (Explain that these short sequences of code represent alleles of the gene that controls the height of pea plants. The codes listed are only a partial segment of a full gene sequence, and do not contain the start codon or stop codon)
·  Display an overhead transparency of the “Circular Genetic Code Table or distribute a copy to students. (Remind students that during transcription, the nucleotide uracil (U) is substituted for thymine (T) in the mRNA sequence, and that during translation, the cell uses triplet codons in the mRNA molecule to specify the amino acid sequences for particular proteins. Also remind students that the ribosome begins reading the mRNA at the position of the first AUG codon. Ask students to use the genetic code table to determine which amino acid AUG corresponds to. (methionine))
·  Instruct students to supply the missing mRNA sequence for Allele 1 in the space provided, and then use the genetic code table to supply the missing amino acid sequence for Allele 1 based on the mRNA codons. (GGU AAA GCU CCU),(Gly, Lys, Ala, Pro)
·  Iinstruct students to supply the missing mRNA sequence for Allele 2 in the space provided, and then use the genetic code table to supply the missing amino acid sequence for Allele 2 based on the mRNA codons. (GGU AAA ACU CCU), (Gly, Lys, Thr, Pro)
·  Have a class discussion about what they found as they performed the sequence analysis on the two alleles. Lead students toward the observation that Allele 1, which results in tall peas, produces a protein that contains the amino acid alanine, while Allele 2, which results in short peas, produces a protein that instead contains the amino acid threonine in that position
Independent Practice: How will my students practice answering the essential question individually?
·  Ask students to answer the following:
1.  How many letters are there in the “genetic alphabet?” What are they? (4: A,G, T, C)
2.  How many letter are there in every “genetic word?” What are they called? (3: codons)
3.  Every word must be translated into 1 of 20 ______?
4.  A “genetic sentence” is made up of amino acids. What is that sentence called? (gene)
Assessment: