Materials Included In Kit

Additional Materials Required

Safety Precautions

This is a pencil/paper laboratory activity and is considered safe. Follow all standard laboratory safety protocols.

Disposal

There are no items for disposal in this activity.

Teacher Tips

• Seven sets of cards allow alternative teaching and teaming strategies. “Cellular chaos” can be created by using just one set and making all students use the same set of RNA Code Cards. If this is done, make a large set of cards and tape them up on the walls of the laboratory. Alternately, set up seven cells with smaller groups working at each cell.

• All materials are reusable.
• Whatever size teams are utilized, separate the cell nucleus (DNA Code Strips) from the cytoplasm area (RNA Code Cards). Tape the DNA Code Strips to the table top so they cannot leave the “nucleus” table.
• Students are the “messengers” and need to physically move between the nucleus and the cytoplasm. Do not put the DNA Code Strips and the RNA Code Cards on the same table.
• Further dramatize the entire lab by creating a nuclear enclosure of some sort. This will force students to enter the nucleus to get the message and leave the nucleus to go to the cytoplasm. Likewise, create a ribosome assembly line area for the translation process.
• The large number of provided DNA fragments allows all students to decode different DNA messages. Check all decoded messages individually as they are completed. Approve them, and then assign additional fragments as appropriate. Be sure to help students if their decoded messages have any “mutations.”
• This activity can be extended by having students create more DNA coded messages from the available words on the RNA cards. Add newly generated DNA codes to your list of available codes for future classes. An entirely new set of RNA messages can be created with new words. Many activities utilizing this concept and set of cards can be created and repeated.

Sample Data

Introduction

DNA, deoxyribose nucleic acid, is the instructions used in the development and functioning of every living organism. Knowledge of its structure and functions is key to an understanding of molecular biology.

Concepts

• Double helix

• Replication
• Genetic code
• Transcription and translation

Background

Less than 50 years ago the nature of the genetic code still eluded scientists. In the 50 years since the structure of DNA was first hypothesized, it has become the most significant biological topic of the century. Understanding the structure of DNA helps to explain many life processes and leads to an understanding of why we are who we are. In this activity, the major processes of DNA will be modeled. Each step of the procedure will simulate a key DNA structure or process.

A simplified diagram of a short section of DNA is shown in Figure 1. The diagrammed segment contains seven base pairs. A real chromosome may contain a single DNA molecule with as many as 10⁸ (100 million) base pairs! Since these base pairs represent the genetic code, the chromosomes can store a lot of messages! A summary of some of the processes of DNA is shown in Figure 2. Refer to these diagrams throughout the activity.

DNA serves as the genetic template and storage place for genetic messages. In order for the messages to be processed, RNA (ribonucleic acid) becomes involved. The first step involves the synthesis of messenger RNA (mRNA) from the DNA template by the process of transcription. This mRNA then carries the transcripted message to the ribosomes where proteins are synthesized. In RNA, thymine is replaced by uracil as the base complement to adenine.

The code in the newly synthesized mRNA undergoes the process of translation and is used to produce a specific sequence of amino acids (i.e., a specific protein). This translation process involves another type of RNA, called transfer RNA (tRNA). The tRNA has a three-base section called the anticodon, which is the key to linking its specific attached amino acid to the growing chain of amino acids. The order in which the tRNA molecules are used is determined by the codon sequence of the mRNA, which, of course, was originally encoded in the DNA in the nucleus.

Materials

Procedure

1. Take the Genetic Code Worksheet to the “nucleus” table assigned by your instructor.
2. Carefully copy (no mutations!) the assigned DNA code onto the Genetic Code Worksheet.
3. Return to your work area and write a transcribed code for mRNA that reflects the DNA code. Do this in the appropriate space on the Genetic Code Worksheet.
4. Next, translate the mRNA code into tRNA code in the space provided on the Genetic Code Worksheet.
5. Go to the “cytoplasm” table and determine the message that is now encoded in the RNA molecules. Write your completely decoded message on the worksheet.
6. Check with your instructor and make sure the genetic decoding work has no mutations.
7. Decode other DNA codes as directed by your instructor.

Student Worksheet PDF

10266_Student1.pdf