The image is of a Braille Key and the DNA Twist Model
Activity

Reading the DNA Code Using the APH DNA Twist Model

In this activity, students who are blind or visually impaired are introduced to the structure of DNA and learn to "read" the code found in the nitrogen bases (the rungs).

Students make their own keys describing the tactile and color surfaces of the nitrogen bases of the model (as shown in the picture on the right). Students who will not benefit from the information about the color may only describe the tactile surface.

Students use these keys to “read” the DNA molecule and to “write” the appropriate code for the corresponding strand of DNA (using base-pairing rules). Finally students will complete a short worksheet in which one strand of the DNA is given and the corresponding strand must be determined.  If students are not yet familiar with DNA base-pairing rules, these should be taught prior to this activity. 

Vocabulary:

Materials

Preparation

Base warm-up worksheet
Download the Warm-up worksheet.
Key for DNA pairs
Download the Key for DNA pairs

Making the Key 

See key attached as a guide.

As students enter the room have the DNA Twist model ready for each student. 

  1. Tell students that they will make a key to use for today’s activity of the DNA model to help them “read” the DNA molecule
  2. Have students make a key with the following information: (See picture)
    • Guanine – blue, bumpy
    • Cytosine – yellow, smooth 
    • Adenine –  white, sandy
    • Thymine – brown, banded

Using the Key 

  1. After students have made the key, explain that DNA is read up and down rather than left to right like English. Explain that if we could cut the molecule down the middle, we would be reading the bases on one side.
  2. Guide students to “read” the nitrogen bases from bottom to top on the right hand side of the molecule and to write down this list of bases. 
  3. Students will use the base-pairing rules – A=T and G=C to write out a complementary strand to the right hand strand. 
  4. Students can check their work by using the left hand side of the DNA molecule as a guide.
  5. Now that students have practiced writing out a complementary strand of DNA using the base-pairing rules, if time allows, have them practice using the attached worksheet

Variations

Younger students and more modified high school classes may not complete the DNA Base-Pairing Activity after the initial introduction. 

NGSS Standards:

Middle School – Growth, Development and Reproduction of Organisms

LS3.A: Inheritance of Traits

High School : Structure and Function 

LS1.A: Structure and Function

High School – Inheritance and Variation of Traits

LS3.A: Inheritance of Traits 

By Laura Hospitál

Collage of reading the DNA code

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