MAKING A MODEL OF DNA and RNA
The purpose of this activity is to use the information you have gained in your study of molecular genetics to construct molecular models that fit all of the criteria in the list below.
Your model(s) must depict a double stranded DNA molecule at least 5 nucleotides in length with an accompanying mRNA strand that is complementary to one side of the DNA molecule.
1. You will work in a group of one to three students to construct your models.
2. You may use any materials you wish. You must provide all of the materials yourself.
3. The model must be free-standing, three-dimensional and large enough for all parts to be seen clearly.
4. If you choose to do a structural model, shapes of all structures must resemble the actual structures. If you choose to do a model of functions, then the objects chosen to represent each part must depict the function of that part. It is not necessary to construct all parts to the exact scale.
5. You must provide a key to the parts of the model and tell whether the model represents DNA or mRNA.
6. The following parts of the molecules must be shown: deoxyribose and ribose sugars, phosphates, and five different bases. You will be responsible for including in your models only the parts which belong there.
Grading
All models will be judged and graded on the following criteria:
1. Scientific accuracy: Does the model contain all the necessary parts? Are the relationships between the parts, if any, show correctly?
2. Sturdiness and three-dimensionality: Is the model truly three- dimensional or is it nothing more than a two-dimensional relief ? Is the model sturdy enough to be moved around without parts of it falling apart? Is it free-standing?
3. Attractiveness and artistic merit: Is the model pleasing to the eye? Are textures and colors used in a pleasing manner? Would the model stand out in a group?
4. Creativity and originality: Is the choice of materials original or are they the usual things one always finds in an elementary school art project? Is there a creative use of materials? Do construction techniques show originality? Is the model unique?
5. Neatness: Is the model neat? Does the construction avoid a sloppy appearance?
Schedule
Stage 1: Assemble in your groups. Discuss how you would like to make your model. Decide what materials you will use and how you will put the model together. Decide where you will meet to construct the models. Decide who is going to bring in each item you need. Make plans for getting all the material s to school tomorrow. Have contingency plans for getting the materials from a group member who might be absent tomorrow. Decide if any of the parts need advance preparation and make arrangements for group members to do these things overnight. Draw sketches of your model to use as a guide. Recheck and make certain you have taken care of everything.
Stage 2: Gather the materials you are assigned to bring. If you can't find something, be sure you call another group member and make arrangements for someone else to bring it in. Do any advance preparation of materials that may be necessary? Pack all your materials and put them in a place where you will be sure to remember them in the morning.
Stage 3: Assemble in groups. Lay out materials. Construct model. Keep checking your model with your sketches and your textbook or other references so that you will make no errors. Make a key to the parts o f the model. Put the names of your group members and their class periods on a card and put it with your model in the spot designated by the teacher. Do not touch any other group's model. Clean up your area. Take all excess materials with you or dispose of them properly.