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Molecular Genetics

By Mark Fairbanks

Games and Activities to Teach Molecular Genetics

Intended Audience

High School Biology


The purpose of this activity is to demonstrate to the biology student that the cell is not a static object. It is a complex functioning unit carrying on those activities necessary for life. This unit will emphasize the role of nucleic acids (RNA and DNA) and cell organelles within the cell as interrelated cooperating and functioning components dependent upon one another for the survival of the whole.


The students will be able to demonstrate a working knowledge of cell interactions such as DNA replication, protein synthesis (transcription and translation), through active participation in a cooperative group.

Curriculum Sequence

This unit will follow the unit in which the students have learned the structures and functions of the cell organelles and cell dynamics. This unit will include instruction in DNA replication, transcription, and translation. The test at the end of the unit will be one in which the students become a living working cell within the confines of the classroom.

Days One and Two: DNA Replication

Objective: The students will demonstrate their understanding of DNA replication by becoming nucleotides and participating in a simulation of DNA copying itself.

Materials: Baby plastic snap beads, detachable DNA plastic model, (free nucleotides), Videos: Protein Synthesis: DNA Replication, Protein Synthesis: DNA the Molecule of Heredity

Anticipatory Set: Several questions should be asked to help the students start thinking about the DNA molecule and its function in the cell.
1. How do cells transfer information from old cells to new cell?
2. What part of the cell's nucleus contains the information to control the cells functions?

Input-Mini Lecture: Discuss the structure of the DNA nucleotide, DNA bonds and double helix nature of DNA.

Modeling-Demonstration: Demonstrate DNA replication using the DNA plastic model.

Input-Videos: Protein Synthesis: DNA Replication, Protein Synthesis: DNA the Molecule of Heredity

Guided Practice-Activity: Half of the students will become DNA nucleotides and connect together forming a double helical strand of DNA. The nitrogen bases of the nucleotides are represented by different color snap beads (green/adenine, yellow/thymine, blue/guanine, red/cytosine). The students become the nucleotide by holding one snap bead in their left hand. The snap bead is the nitrogen base, their other arm is the phosphate group and their body is the deoxyribose sugar. They will form the double helix by holding the shoulder of the person on their right with their free arm and snapping the snap bead with the person opposite them. There will be two lines of students facing each other.

Students at the head of the line will unsnap their beads representing the unzipping of the DNA. The other half of the students in the class will be the free nucleotides in the nucleus. They will then move between the two strands of the unzipped DNA. Where they will match up with the complimentary nitrogen base and snap together. Finally, they will grab the shoulder of the person on their right symbolizing the formation of the covalent bonds between the sugar and phosphates of the DNA molecule. The end result will be two double strands of DNA.

Checking For Understanding-Short Essay: In their own words the students write a paragraph describing the structure of DNA and DNA replication.

Closure: Restate the original question and have students choose one of the questions to reflect upon as a written homework assignment.

Day Three and Four: Protein Synthesis (Transcription and Translation)

Objective: The students will demonstrate their understanding of protein synthesis by becoming a DNA molecule , mRNA molecule, and tRNA molecules. They will demonstrate the construction of a protein.

Materials: baby plastic snap beads, baby plastic snap stars, detachable DNA plastic model, (free nucleotides), Videos: Protein Synthesis: RNA synthesis, Protein Synthesis: Ribosomal RNA the Protein Maker, Protein Synthesis: Transfer RNA the Genetic Messenger, Protein Synthesis: Protein the Stuff of Life

Anticipatory Set: Several questions should be asked to help the students start thinking about protein synthesis including transcription and translation.

  1. How is the information in the DNA use to control the functions of the cell?
  2. What are the roles of RNA in this process?

Mini Lecture: Review the structure of the DNA molecule. Introduce how the mRNA is transcribed and translated into a protein using tRNA.

Modeling-Demonstration: Demonstrate the production of a protein using plastic models.

Input-Videos: Protein Synthesis: Ribosomal RNA the Protein Maker
Protein Synthesis: Transfer RNA the Genetic Messenger

Guided Practice-Activity: The students will become the DNA molecule, messenger RNA, and transfer RNA and create an active model in the classroom to produce a plastic model of a protein.

In a class of 30 have 16 students become a DNA molecule with the sequence CAGACTTA an its complimentary code of GTCTGAAT as in the previous activity (green/adenine, yellow/thymine, blue/guanine, red/cytosine). Then have 6 students be complimentary mRNA nucleotides for the middle six nitrogen bases of the CAGACTTA side of the DNA molecule. The complimentary strand of mRNA will be UCUGAA with the purple snap bead for the nitrogen base uracil. Next have 6 students become the anti-codon for the two codons of the messenger RNA sequence with will be read off the DNA. They should have the sequences AGA and CUU. Finally have two students become amino acids that will attach to the transfer RNA with the anti codon of AGA (serine) and CUU (glutamic acid). If you have a smaller class have the DNA chain become one pair of nucleotides shorter and substitute plastic stars for the students who were the amino acids.

Once the roles have been assigned the students of the DNA molecule should arrange themselves in the the proper sequence. Next in transcription, have the complimentary base pairs match up to form the double strand of the DNA molecule. Now have the DNA strand unzip its six middle nitrogen base pairs. You can act as the protein which helps in the unzipping of the DNA molecule. The free mRNA nucleotides should match up with the complimentary nitrogen bases of the AGACTT side on the unzipped section of the DNA molecule. You can now become the protein which helps the free nucleotides match up followed by becoming the protein which connects the sugar and phosphates along the side of the mRNA single strand. If you do not become the proteins then you should have the student match up and then form the covalent bonds on their own. Now have the students unzip the strand of mRNA from the DNA and leave the nucleus. The DNA may then re-zip to form the double strand.

Now have the students which became the mRNA move out into the cytoplasm of the cell and attach to a desk or counter which represents the ribosome. The translation of the mRNA will now begin. The students which represent the tRNA must have the complementary sequence to match up with the mRNA on the ribosome. Before they move to the mRNA they must pick up the correct amino acid which is one of the students. The students who are the amino acids may wear a tag which labels the amino acid that they are to enable the tRNA to match up. After the two tRNA sequences have attached to their amino acid by holding hands they need to move to the mRNA and match up their anti-codon with the codon. Now they need to snap their beads together. The second tRNA will then come in and repeat the sequence that the first tRNA did. Then the two amino acids will connect at the elbow to symbolize the polypeptide bond. Finally, the first tRNA will leave. This will complete the simulation with the beginning of the protein. The teacher should ask the students what will happen next in the production of a continuing chain of amino acids.

Checking For Understanding-Short Essay: In their own words the students write a paragraph describing roles of DNA and RNA in the production of a protein

Closure: Restate the original question and have students choose one of the questions to reflect upon as a written homework assignment.


The original concept for this lesson originated with Bill Forward from Rio Linda Senior High School at 6309 Dry Creek Road in Rio Linda, CA. 93446.

Days Five and Six: Conceptualization of the Cell

Objective: Given basic instructions and materials the learning group should be able to organize itself into a class simulation of a functioning cell. Given a card with the name of a specific organelle of the cell the learner should be able to describe what that organelle's functional relationship to the other organelles of the cell. Upon completion to this activity the learner will be able to contrast at least three activities that the organelles of the cell have to perform in order to maintain life. Upon review of the learning group's video the learner should be able to critically analyze the role playing of himself/herself and other students, and make constructive criticism as to the appropriateness of the activities being performed compared to the given functions of the various parts of the cell.

Materials: 5"x7" cards with the name of the organelle to be drawn, Narrator (1), Nucleus: including nuclear material(1), Messenger RNA (5), Transfer RNA (5+), Ribosome (5+), Defective Ribosome (1), Golgi Apparatus (3), Mitochondria (3+), Lysosome (2), Cell Membrane (1+), 5"x7" Role identification cards for the above organelles, Paper bags, Baby plastic snap beads, Baby plastic snap stars (ATP molecules), Card with "nuclear, Video camera, TV Monitor

Anticipatory Set: Ask students to review the roles of the organelles of the cell. Review to clear any questions then ask the following questions,
1. What would it be like to be an observer within a living cell?
2. What activities would be readily apparent?
3. If you could be any organelle which one would you be and why?

Input: Introduce the Ground Rules for the quiz: no talking once the quiz has started; each student will draw an organelle and will play the role of that organelle during the quiz; the student who draws the narrator has the option to trade with any other student (this is important as the narrator is a key figure in the process); the area between the tables/desks will serve as the endoplasmic reticulum; the nucleus does not have to be centrally located, but is stationary, as are the ribosomes and the cell membrane; every two mistakes that are made will drop the class's grade by one letter; other classes may view the video and this class will be allowed to view other classes; after the roles are drawn there will be a fifteen minute period allowed for class organization.

Modeling: Show the students the materials available ( they have seen the ATP models prior to the activity) : and show the use of the plastic snap beads for bonded amino acids, also drop the hint that the paper bags could be used for packaging; walk around between the rows as the role of the endoplasmic reticulum is suggested. Point out the importance of a good leader and the group cooperation needed to make the activity successful. It is not necessary for every student to know what every other student is doing. All that is to be known is what your own function is and what organelles you relate to.

Checking for Understanding: Ask for a show of hand of those students who understand. Point out that these students are among those who should take a leadership role in setting up the activity. When the instructor has a pretty secure felling that the class has the idea, the instructor should leave the picture and allow the student leaders to emerge. If the class is trustworthy, the instructor may even consider leaving the room.

Independent Practice: After the 15 minutes of organizational time has passed the instructor along with the narrator will enter the room, video camera running. The narrator should introduce himself/herself and period being filmed. The instructor and the narrator should move about the room filming the various organelles of the cell at work. The instructor should ask question prompts of the narrator as to the activities taking place. Questions may or may not be leading depending on the ability of the narrator. All students should be filmed. The object of this activity is to insure student success and to give credit where credit is due! Be kind!!! The stress level can be high.

Closure: After the class has functioned as a cell for five minutes or until all students and activities have been filmed, reorganize the class into a discussion group. Show the video to the group first without the audio allowing students to comment as they see fit. This will be a fun experience for the students and the instructor alike. Show the video again, this time with audio and ask for critical analysis. Have students record comments and thoughts concerning the lesson. Restate the initial questions asked of the student at the beginning of class. Have the student choose one or two or those questions to reflect upon as a written homework assignment.

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