DNA Replicator in Scratch

Welcome back! In this tutorial we will be creating program that replicates a strand of DNA, representing each of the four nucleotides with letters (A for Adenine, T for Thymine, C for Cytosine, G for Guanine).

Objective: Understand how two list datatypes can interact with each other.

Final Product:

The process by which DNA, the fundamental molecule of life encompassing the library of your genetic information, is regulated by Chargaff's rules. This stipulates base pairing (Adenine is paired with Thymine; Cytosine is paired with Guanine). This means that if you are replicating a DNA sequence you will replace "A" with its compliment "T" and "C" with "G" (and vice versa: T w/ A and G w/ C). This is fundamentally how the program operates. 

Graphical Template: Link


Expansion: How can you change the rules in order to create RNA where bases of adenine are converted to uracil instead of thymine? RNA is a molecule typically used to transfer genetic information out of the nucleus (the special compartment in a cell where DNA is held). Give it a try!

Completed Project: Link