LEGO DNA Activity

Here’s a super fun DNA activity for middle school that uses one of our favorite materials… LEGO bricks!

You can actually use this activity for kids in 5th grade up through high school biology. Anytime you are teaching DNA in a life science unit or biology course, this would be appropriate.

Building a model of DNA is a valuable activity for students because it helps transfer the knowledge to their long-term memory. Manipulating the LEGO bricks and making decisions about which nucleotide bases go where uses more of the brain than simply reading about DNA or listening to a teacher talk about it.

What is DNA, and what does it do?

DNA is a code for genetic information. The order of the nucleotide bases in a strand of DNA is very specific. Each group of three bases is called a codon, and each codon is a code for a specific amino acid. In other words, DNA tells your body which proteins to make to build the body structures that make you – YOU!

Supplies Needed for this LEGO DNA Activity:

These are the bricks we used, but you can modify this activity based on what you have.

• Two 16 x 16 plates
• Red bricks for the sides of the ladder shape
• 1 x 4 bricks in five different colors for the nucleotide bases. You’ll need 5 bricks of each color.

A strand of DNA has a double helix structure, which looks like a twisted ladder. I thought about building the twisted shape, but that would definitely require a lot of special LEGO elements that most kids (or teachers) would not be likely to own, or at least not own in the quantity that would be needed. So I decided to just go with a flat ladder shape.

The sides of the ladder are made up of sugars and phosphates. We used red, but you can use any color of bricks for this! Another option is to use two colors – one for the sugars and one for the phosphates. You can alternate sugars and phosphates in your ladder.

The rungs of the ladder are made of nucleotide bases. There are four nucleotide bases: adenine, thymine, cytosine, and guanine.

Choose four LEGO colors to represent these four bases.

Then build one side of the strand by adding bases in any order.

Complete your strand of DNA by adding the nucleotide bases that pair with them. Adenine bonds with thymine and cytosine bonds with guanine.

DNA is located in the nucleus of our cells, but the ribosomes are the parts of the cell that make proteins. So how does DNA tell the ribosomes what to do?

The answer is mRNA (messenger RNA) and tRNA (transfer RNA). RNA is a bit different from DNA in that it only has one strand. It also has one difference in the nucleotide bases – uracil takes the place of thymine. The purpose of RNA is to serve as a messenger between the nucleus and the ribosomes.

The first step in manufacturing mRNA is that DNA is “unzipped” by enzymes. Nucleotides then line up along the unzipped DNA. Adenine and uracil bond, and cytosine and guanine bond. However, once the strand of mRNA has formed, it separates from the DNA. The DNA is then zipped back up again. The strand of mRNA then leaves the nucleus and carries the code to the ribosomes.

This explanation is not a complete lesson on protein synthesis, and it’s not designed to take the place of your textbook! If you need more information on protein synthesis, here’s a really good video on YouTube that explains the whole process with helpful graphics.

Need more hands-on science ideas?

Here’s a collection of 45+ Science Experiments for Elementary and Middle School!