I would recommend building a stick model model of DNA

Only 10 or 12 nucleotide sequences

Then make a play doe model of the coils and folding ribbons that allow 6 feet of DNA to scrunch up in the nucleus of a microscopic cell.

On your display you could show a picture of the molicuel that splits DNA and replicates it polymerase.

To copy DNA, polymerase requires two other components: a supply of the four nucleotide bases and something called a primer. DNA polymerases, whether from humans, bacteria, or viruses, cannot copy a chain of DNA without a short sequence of nucleotides to “prime” the process, or get it started. So the cell has another enzyme called a primase that actually makes the first few nucleotides of the copy. This stretch of DNA is called a primer. Once the primer is made, the polymerase can take over making the rest of the new chain.

The next step does the same thing as opening a book to the page that you want to copy, then laying it on the copier. The DNA molecule has to be unzipped, then the section of DNA which has to be copied must be read. This step is performed by the enzyme polymerase. Polymerase pulls the halves of DNA apart, then reads the nucleic bases, whether it is adenine, cytosine, guanine, or thymine.

Now here is the tricky part. Polymerase starts with the leading strand, starting at the end of the DNA molecule’s leading strand, and reading the nucleic bases one-by-one until polymerase reaches the other end.

You could also look at and compare alternative energy sources such as windmills, solar, etc.

I hope this helps.

Good Luck!