DNA Model

It's time to make some DNA.  First, watch this brief DNA intro.

Part 1: DNA Challenge

Students make a section of a DNA molecule.

• Students are assigned to be one of the four DNA bases, A (adenine), T (thymine), C (cytosine), or G (guanine) and wear labeled lanyards.

• Students need to pair with their appropriate bases (A with T and C with G) by looping the lanyard cards together and extend the DNA molecule by hooking or touching elbows with the bases on either side.

• Students create a double helix for the following DNA sequence.

• Here is the DNA base sequence: TCA  -  CCA  -  CTA  -  TGC

• And the amino acid sequence: Serine - Proline - Leucine - Cysteine

• Each 3-base sequence codes for a different amino acid, and the amino acids are used to make proteins.

Debrief Questions:

1. What positives can you take away from the activity?

2. What was your role and how well do you feel you contributed to this task?

3. How did you communicate your ideas?

4. What advice would you give to another group working on this challenge?

Optional Extension: Watch the 2-minute DNA Transcription in Real Time video.

Part 2: Complete Hemoglobin DNA Section

We are collectively going to make a model of the DNA that codes for a hemoglobin protein.  Hemoglobin is what attaches oxygen to our blood cells.

Here is (part of) the genetic code for hemoglobin:

Sickle cell anemia is a disease that keeps oxygen from properly attaching to blood cells.  It is caused by a mutation - see that it is caused by only one of the thousands of base pairs being wrong. Note: our class will be making the sections in yellow, which are the parts that actively code for the hemoglobin protein.

Here is the procedure to follow on day 1 to get set up to make your DNA molecule.  Make a few extra pairs and maybe one extra long piece in case anything breaks or goes missing before tomorrow, when you'll actually assemble the DNA. 

On day 2, find your two long pieces and 10 pairs and assemble them into a double helix as shown below:

• Make sure to follow the right hand rule (counter-clockwise rotation as you move down the strand, making ~1/4 turn per 10-base section/piece)

In our model, we will use this color coding scheme for the base pairs.

To help avoid mutations, tape your tag on to your strand as shown below.

Color code your tag as shown below. 

Use the following guidelines to properly color all your base pairs.

Using masking tape, connect all the sections of DNA into the proper sequence and throughout the day hang them near the ceiling around the classroom.

When you finish, read the Hemoglobin article. 

When you finish reading the article, answer the Hemoglobin article questions.

DNA Model Extension: Origami DNA

Look up an origami DNA template that you can print, color, and make. Then make at least four strands of Origami DNA.