Activity 4.2:
Genetically Modified Hopscotch
(optional)

Directions

Remind participants that DNA is written in the chemical bases, A, G, C and T that is translated into RNA. RNA is complementary to the DNA.

• Explain what it means that RNA is complementary to DNA? Note to leader: Participants will learn more about this in the Dessert activity).

• Can you discuss why you think it is important that RNA is copied exactly as the DNA is?

The protein synthesizing machinery reads the chemical bases in groups of three, inserting a specific amino acid for each triplet in the RNA using the genetic code (Handout 4.2). The amino acids are strung together to make a protein and that protein has a specific function in the cell, just like the enzyme in your spit that broke down the starch in the cracker to make sugar. Today we will create a genetic code with hopscotch and then translate that code into a protein.

How to Play

Find a level cement surface and draw two identical hopscotch courts with sidewalk chalk following the hopscotch court diagrams shown in the Leader Supplement for Activity 4.2. Each box should be about 18 inches square. Have participants put either an A, G, C or U in each box, as shown. This will help familiarize them with the chemical makeup of RNA. Draw a two-foot line a few feet from the bottom of the diagram where players will stand to toss their markers.

Divide participants into two teams and start each team at the line for one of the hopscotch courts. One player from each team throws their marker. To start their protein, they must get their marker first on an "A". If they do not, the second player tries to land on the "A". Once they get the marker on the "A", they hop on one foot when there is a single square (without a marker) and on two feet when there are two squares across the court. Participants must miss jumping in the square with the marker. They lose their turn if they step on the square with the marker or step on a line. Once the individual reaches the final square, marked REST, he/she turns around and comes back, retracing their steps and stopping at the square with the marker. The participant must then bend down, pick up the marker and return to the beginning line. After the "A", the next player must get a "U" and finally the third player a "G".

Once the team has "AUG", which is the starting codon for almost all proteins, they continue throwing their markers on any square to make a protein of 5 amino acids using sets of 3 bases (for a total of 15 bases). One participant keeps track of each base on the sheet of paper. Each team must end their five-amino acid protein by landing their markers on a stop codon, "UAA, UGA or UAG". If a team gets a stop codon before they have 5 amino acids, they must toss their marker again to get a triplet for an amino acid. Once they have 15 bases, they separate the bases out in the order in which they were generated, into triplets. They then construct their protein by converting the base sequence into an amino acid sequence using Handout 4.2.

Once both teams finish, they should check the sequence of the other team to make sure they read the amino acids correctly.

Challenge the players with the following:

• Why do you think you had to land first on the "AUG" before you could start building your protein?

• Explain what you think would happen if you landed on "UAA, UGA or UAG" before the entire protein sequence was completed.