Activities
DNA and Protein Synthesis Guided Inquiry
NOTE: It is assumed that students have a cursory knowledge of the structure of DNA; (the nucleotides, rules of base pairing, various functions of RNA) as well as an understanding of ribosomes and their role in protein synthesis. Although the activities will review these concepts, they will not reteach all aspects of these concepts.
Protein Synthesis POGIL
Objective: To Analyze the biochemical processes that translate information stored in the DNA into sequences of amino acids.
Standard: CCSS.ELA-Literacy.RST.11-12.9
Instruction: Genetic information stored in the DNA contains all of the necessary information for the synthesis of biochemicals that direct all aspects of an organism’s survival. An organism’s genetic information (its genes) is stored as a sequence of nucleotides (Guanine (G), Cystine (C), Thymine (T), and Adenine (A)), that are paired with their complements in the DNA double helix. Given sections of the DNA (genes) code for the specific proteins that direct and control cellular functions. This activity will guide students through an inquiry that explores protein synthesis.
Task One: Once the DNA helix is separated: use the rules of base pairing to create an mRNA copy of the sequence: your strand should be at least twenty-one base pairs (b.p.) long.
Task Two: Once completed use a strand of mRNA and the genetic code guide to translate sets of three b.p.’s into their corresponding amino acid.
Task Three: Assemble the amino acid sequences into a chain.
Additional Information: DNA sequences must be translated with fidelity in order to ensure that amino acids are sequenced correctly. Insertions or deletions of the DNA code alter the amino acid sequence which can lead to frame shifts mutations. These mutations can disrupt the proper translation of the cell’s genetic information.
Task Four: Using your mRNA strand remove one to three base pairs. Use this altered strand to carry out your protein synthesis. How does this new sequence compare with the original?
Could this new sequence code for the same protein? How would this affect the cell’s processes?
CRISPR – Cas 9 Guided Inquiry
Objective: To Analyze the CRISPR – Cas 9 Immune Response
Standard: HS-ETS1-4 Engineering Design
Instruction: Bacterial cells use the CRISPR array and associated Cas proteins as an immune response. Upon reinvasion the cells use the segments stored in the array to guide the Cas proteins that cleave the invading genome. This is a collaborative activity in which groups of students (at least four per group) build a CRISPR array.
Task One: Each group of students will receive a DNA sequence of an “invading genome”: (NOTE: there should be at least 6 sequences for this activity). Each group will select a protospacer sequence (approximately 15 -20 b.p.) that they will be incorporated into the CRISPR array (students also should note the PAM sequence on the DNA sequence). Each group’s sequence will be used to build the CRISPR array.
Task Two: Each student group will translate their DNA sequence into an RNA copy (the crRNA) which serves as the guide RNA. Each group attaches their crRNA to a cutout representing the CAS protein. The complex will serve as a facsimile of the CAS protein complex.
Additional Information: The series of associated CAS protein complexes are used to defend against reinvasion. When this occurs, the CAS complexes use the guide sequences to identify the invading genome which is cleaved by Cas proteins.
Task Three: Groups will interchange their CAS protein complexes. Teacher will show each of the original DNA sequences; student groups will determine which CAS protein corresponds to the genome and thence simulate cleavage by the CAS proteins. (Note: Students will need to identify the appropriate PAM sequence of the genome before “cleaving” the DNA.)
Practical Applications of CRISPR Technology: Independent Research
Objective: To evaluate the practical applications of CRISPR Technology
Standard: HS-ETS1-1 Engineering Design
Instruction: While bacteria use CRISPR as an immune response, the system can be used to modify an organism’s genetic structure. Once the CAS complex cleaves an organism’s DNA the cell will use either Non-Homologous End Joining (NHEJ) or Homology Directed Joining (HDJ) to repair the break. Each of these processes can be used by researchers to alter (or remove gene sequences) or to insert genetic information.
In this activity, students will engage in a web quest to research the applications of CRISPR in a variety of fields. The teacher will list the various fields in which the technology is currently being used. Each student group will select one application and prepare a brief explanation of how CRISPR is being used, along with the proposed benefits and possible consequences its use poses to society.
Gene Drive Technology Directed Modeling Activity
Objective: To analyze how gene drives alter traditional patterns of Mendelian inheritance
Standard: HS-ESS3-4 Earth and Human Activity
Note: Students should have a cursory knowledge of Punnett squares and a basic understanding of Mendelian laws of inheritance.
Instruction: In traditional patterns of inheritance in sexually-reproducing organisms, each offspring receives a gene from each parent. This is true for each successive generation; thus, each gene has at most a 50% chance of being passed on. This activity begins with a brief analysis of three generations to verify this pattern. Students should note that inherited genes remain the same across the generations.
Task One: Each group of students will be given two sets of alleles (father and mother) which they will cross (for this activity the alleles should be heterozygous). Students should complete Punnett squares for at least four generations.
Additional Information: When a gene drive is employed one gene has the capacity to overwrite the genetic information of an inherited gene (designated as the wild type for this activity). In this manner the frequency of the designed gene will steadily increase with each successive generation.
Task Two: Students will repeat task one; however, one of the genes that are passed on will be a gene drive gene. Students should complete task one and notice the gradual increase in the frequency of the gene drive gene: eventually every offspring will carry the gene drive gene.
Additional Information: There are many proposed uses for gene drive technologies. Students and teacher will explore these proposed uses of the technology and add them to the list generated during the previous research activity.
Ethical Dimensions of Genetic Engineering: Guided Research
Objective: To evaluate the ethical, societal, and environmental consequences of bioengineering technology
Standard: HS-ETS1-1 Engineering Design
Instruction: Students will use their research on the benefits and consequence of genetic engineering to create a position paper. The class will first engage in a structured discussion to elicit as many perspectives as possible. Each group will take notes and then use their collected information to answer the guiding question: “Should We?”.
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