Video narration
If living things came with an instruction manual, what would it be made of? Not paper—molecules. Inside almost every cell is DNA: deoxyribonucleic acid. Think of it as a long, twisted ladder, packed tightly into a tiny space. The “rungs” are like letters in a code, and the order of those letters stores information—how to build and run an organism. Different stretches of DNA are genes, which act like specific instructions for making particular parts and tools, usually proteins. When cells grow and divide, they copy this DNA so new cells inherit the same set of instructions. And over many generations, small changes in the code can create differences between individuals—that’s why DNA links families, explains traits, and helps scientists track evolution and disease. DNA is biology’s information molecule: a chemical story written inside you.