Codon Critters. High School

Transcription

1 Codon Critters High School This activity can be done as an example of deciphering a complicated code, or as part of a in-depth study of DNA. The cube demonstrates RNA s role in transcription and translation by acting as a string of mrna carrying the 18 traits for an imaginary creature the students will make. Each row on the cube will code for a single amino acid and to simplify things, t raits are determined by just one amino acid. This activity can be done individually or in pairs, and can be s implified by working in groups where each student is responsible for only a fraction of the whole cube (1 side only, 2 sides, etc) and then the group can collaborate on the drawing, or each student can draw their own creature. Texas Essential Knowledge & Skills (TEKS): Biology.6A ( A, C-F) Science concepts. The student knows the mechanisms of genetics, including the role of nucleic acids and the principles of Mendelian Genetics. The student is expected to: (A) identify components of DNA, and describe how information for specifying the traits of an organism is carried in the DNA (C) explain the purpose and process of transcription and translation using models of DNA and RNA; (D) recognize that gene expression is a regulated process; (E) identify and illustrate changes in DNA and evaluate the significance of these changes; (F) predict possible outcomes of various genetic combinations such as monohybrid crosses, dihybrid crosses and non-mendelian inheritance;

2 Objectives: Students will use Rubik s Cubes to model RNA s role in transcription and translation. The cube acts as a string of mrna carrying the 18 traits for an imaginary creature the students will make. Developing a nd Using Models: Modeling in 6 8 builds on K 5 experiences and progresses to developing, using, and revising models to describe, test, and p redict more abstract phenomena and design systems. Materials: 1 Rubik s Cube per group Cube Critter handout (1 per student) Codon Table (1 per student/group) Table of Traits (can be shared) Unlined paper Colored pencils or markers Background Knowledge: Students should have understanding that: Hereditary information is contained in genes, located in the chromosomes of each cell. An inherited trait of an individual can be determined by one or by many genes and a single gene can influence more than one trait. The characteristics of an organism can be described in terms of a combination of traits. Although different species might look dissimilar, the unity among organisms becomes apparent from an analysis of internal structures and the similarity of their chemical processes. Vocabulary : adenine DNA transcription amino acid guanine translation codon thymine cytosine traits

3 Procedure: Before class: Make copies of handouts for students/ groups. (Codon Critters, Codon Table, Table of Traits) With students: 1. Explain how to use a codon table. Left side is the first base, top is the second base, right side shows the last base. 2. Explain some details necessary for this activity: a. Point out to students that the center square on each face of the Rubik s Cube is fixed, so that s how the faces are named. When referring to the yellow face. this means the face of the cube with a yellow center tile. b. The diagram at the bottom of the handout shows a way to look at the cube so everyone is using the same row for the same trait. It s not absolutely necessary that everyone does this, but it helps illustrate that even when reading everything the same way, odds are you re going to have different traits. 3. Distribute Cube Critters handouts to students. Read through instructions together. 4. Give each student (if working individually) or group a Rubik s Cube. The cubes can be already scrambled, or if the start with solved cubes, instruct the students to mix up the cube by performing at least 10 random turns. 5. Be available to help students as they work through the activity. Technology Connection Students can practice transcription and translation with this online activity:

4 A teacher s answer key is available for download at The file is called Codon Cube C ritters Checker.xls and a how to use video is online: Optional follow-up/ Extend the lesson The creatures can also be sorted into into classes, orders, families, etc based on characteristics of the student s choosing. Students should explain and justify their classifications. Notes to Teacher: 3x3 Rubik s Cubes are available to borrow from the You CAN Do the Rubik s Cube Lending Program at no cost other than return shipping. Thank you to Adam Raymond, math and physics teacher at Rockdale Magnet School for Science and Technology (Georgia), for the teacher s answer key for this lesson.

5 Cube Critters: Student Page All of life as we know it is based off of DNA. Everything from the smallest and simplest organisms to the biggest and most complex creatures ever to live all begin with guanine, cytosine, adenine and thymine. To better understand the universal nature of DNA and to show how four things can create an almost infinite combination of traits, we are going to work with something most (if not all) of you are familiar with: the Rubik s Cube. Despite being composed of only six colors and 20 moveable pieces, there are 43,252,003,274,489,856,000 unique combinations that can be made on a Rubik s Cube. To put that into perspective, all 7 billion people alive on Earth today would need over 600 million cubes each to make all of the combinations. For this reason alone, the Rubik s Cube is perfect for our study of transcription and translation. In DNA, a codon is 3 bases read together and on your Rubik s Cube, a codon will be three squares in one row of the cube. Each codon will code for an amino acid and in our simplified version, each amino acid will determine a trait. By the time you finish, you will have determined 18 individual traits for your organism and will then illustrate your newly designed critter.

6 Activity Instructions: The center square on each face will never change its place. When a side is mentioned by color (for example: the green side), it is referring to the side with a green square in the center spot. Each side of the cube will code for 3 specific traits, all fitting a common theme. To insure that everyone reads their code the same way, the traits will be named in the following manner: Note the order of the colors of the cube when solved: The traits will be read in this order for each side: 1 signifies the first trait for that color s face, 2 the second, and 3 the third. The letters a, b, and c refer to the first, second, and third base respectively for each given trait. Each color face will determine 3 different traits.

7 Procedure: 1) Scramble your Rubik s Cube thoroughly. Make at least 10 random turns. 2) Place the cube on your desk with the yellow face on the top and the orange face towards you. 3) Beginning with the top left corner of the yellow face, record the arrangement of your cube in Data Table 1 (It may be helpful to write down both the color on the cube and the base in the area provided.) 4) For each set of three bases, find the corresponding amino acid on the Codon Table. 5) Repeat steps 3 and 4 for the orange and blue faces. 6) After recording the information for the yellow, orange and blue faces, flip your cube over so the white face is on top now and the green face is towards you. 7) Repeat steps 3 and 4 for the three remaining faces. 8) After filling in the amino acids for all traits, complete Data Table 2 by writing the amino acid for each trait from Data Table 1 into the appropriate box and matching the amino acid to the trait description. 9) Once all trait descriptions are written, draw a quick sketch of what each trait will look like in your finished critter. 10) Carefully Draw and color a detailed image of your newly created critter on a separate sheet of paper, making sure to include all 18 of the traits in your drawing. Codon Table *In a real codon table, the codons UAA, UAG, and UGA are considered stop codons where translation would end. For this activity, they are replaced with two imaginary amino acids fakeinine and pretendisine, and translation should continue.

8 Green (G) = Guanine (G) Yellow (Y) = Adenine (A) White (W) = Uracil (U) Blue (B) = Cytosine (C ) Red (R) (on face with Yellow, Orange or Blue center) = Guanine (G) Red (R) (on face with White, Green, or Red center) = Adenine (A) Orange (O) (on face with Yellow, Orange or Blue center) = Uracil (U) Orange (O) (on face with White, Green, or Red center) = Cytosine (C ) Data Table 1 Face Row EXAMPLE Base 1 Base 2 Base 3 Amino Acid Color = Base Color = Base Color = Base G = G Y = A W = U Aspartic Acid Yellow Orange Trait 1 = = = Trait 2 = = = Trait 3 = = = Trait 1 = = = Trait 2 = = = Trait 3 = = = Trait 1 = = = Blue Trait 2 = = = Trait 3 = = = White Green Trait 1 = = = Trait 2 = = = Trait 3 = = = Trait 1 = = = Trait 2 = = = Trait 3 = = = Trait 1 = = = Red Trait 2 = = = Trait 3 = = =

9 Data Table 2. Face Row Amino Acid Description Y E L L O W O R A N G E B L U E W H I T E G R E E N R E D Trait 1- General Appearance Trait 2- Body Size Trait 3- Body Type Trait 1- Base Color Trait 2- Pattern Color Trait 3- Pattern Trait 1- Leg Length Trait 2- Tail Type Trait 3- Foot Type Trait 1- Muzzle Trait 2- Ears Trait 3- Eye Color Trait 1- Wings Trait 2- Fire Color Trait 3- Horns Trait 1- Biome Trait 2- Time of Activity Trait 3- Egg Type

10 Trait 1: Coverings YELLOW Face = Appearance Fur Feathers Scales Smooth Trait 2: Body Size Dog-Sized Horse-Sized Bear-Sized Elephant-Size d Trait 3: Body Type Skinny Medium Large Chunky

11 Trait 1: Base Color ORANGE Face = Colorations White Black Brown Orange Yellow Glutamic Acid Blue Green Purple Red Aspartic Acid Trait 2: Pattern Color White Black Brown Orange Yellow Glutamic Acid Blue Green Purple Red Aspartic Acid Trait 3: Pattern Stripes Dots Rings Blotches Hearts Glutamic Acid Aspartic Acid

12 WHITE Face = Head Structure Trait 1: Muzzle Short Long Short Beak Long Beak Curved Beak Glutamic Acid Aspartic Acid Trait 2: Ears Short Pointed Long Pointed Short Floppy Long Floppy Dumbo Glutamic Acid Aspartic Acid Trait 3: Eye Color Blue Green Black Red Aspartic Acid Glutamic Acid

13 Trait 1: Leg Length BLUE Face = Extremities Very Short Short Medium Long Very Long Trait 2: Tail Type None Nub Medium Long Two Tails Trait 3: Foot Type Hoof 3-Toed No Claws Short Claws Long Claws

14 Trait 1: Wings GREEN Face = Fantastic Add-Ons None Bird Insect Dragon Fairy Trait 2: Fire Color Red Orange Yellow White Blue Green Trait 3: Horns Antlers Small Pointy Big Pointy Curly None

15 Trait 1: Biome RED Face = Environment Desert Forest Plains Arctic Trait 2: Time of Activity Day (Diurnal) Night (Nocturnal) Dusk/Dawn (Crepuscular) Fakenine Trait 3: Egg Type Blue Speckled Red Speckled Striped Solid White Solid Brown