--- title: "DNA & Genes" description: "Describe the double helix structure of DNA (base pairs, complementarity), explain how genes are sections of DNA that code for proteins, introduce the central dogma (DNA → mRNA → protein) conceptually," canonical: https://lightmysky.com/learn/science/dna-and-genes-mt_0sELh0MYWb source: https://lightmysky.com/learn/science/dna-and-genes-mt_0sELh0MYWb.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # DNA & Genes Describe the double helix structure of DNA (base pairs, complementarity), explain how genes are sections of DNA that code for proteins, introduce the central dogma (DNA → mRNA → protein) conceptually, and discuss the ethical implications of CRISPR gene editing — including potential benefits (genetic disease treatment) and concerns (germline editing, 'designer babies') Subject: Science · Area: The Human Body · Ages 12 to 14 Page: https://lightmysky.com/learn/science/dna-and-genes-mt_0sELh0MYWb ## Ready when they can - Describes DNA as a double helix with four bases (A, T, C, G) where A pairs with T and C pairs with G - Explains that a gene is a section of DNA that codes for a specific protein, and that proteins carry out most of the body's functions - Describes CRISPR as a molecular tool that can cut and edit DNA sequences, and raises at least two distinct ethical considerations about its use in humans ## Lesson: The Code Inside You: DNA and Genes Inside almost every cell in your body is a molecule called DNA. DNA is shaped like a twisted ladder, called a double helix. The order of its rungs helps shape how you grow and how your body works. The rungs of that ladder are made of four chemical bases: A, T, C, and G. These bases only pair up in one fixed way: A always pairs with T, and C always pairs with G. That pairing rule lets each half of the ladder work as a backup copy of the other half. *(drawing: This strand reads A, T, C, G. The matching strand underneath would read T, A, G, C, since A pairs with T and C pairs with G.)* A gene is a specific section of DNA, like one recipe inside a very long cookbook. Many genes hold the instructions for building proteins. Proteins are the molecules that do the work in your body: they build muscle, carry oxygen in your blood, and fight off germs. One gene can be used in more than one way, so it can help make different proteins. Some genes make working RNA molecules instead of proteins. You have thousands of genes in your DNA. *(drawing: In this protein-building path, DNA is copied into mRNA, and mRNA is used to build a protein.)* Scientists built a tool called CRISPR that can find a specific spot in DNA, cut it, and edit the sequence there. CRISPR could one day fix genes that cause inherited diseases. But editing DNA in eggs, sperm, or embryos, called germline editing, could pass those changes to future generations. That is why many scientists worry about 'designer babies' and think human CRISPR use needs strict limits. **Recap.** DNA is a paired code of A-T and C-G, many genes in that code hold instructions for building proteins, one gene can help make different proteins, and CRISPR can edit the code, which offers real medical hope alongside real ethical questions. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Chromosomes, Genes & DNA](https://lightmysky.com/learn/science/chromosomes-genes-and-dna-mt_6aJUzBYGNs) ## Opens up - [Predicting Inherited Traits](https://lightmysky.com/learn/science/predicting-inherited-traits-mt_o7FJPDsHiW) - [DNA Structure and Base Pairing](https://lightmysky.com/learn/science/dna-structure-and-base-pairing-mt_PK4uNJeg_k) - [Cancer & Stem Cells](https://lightmysky.com/learn/science/cancer-and-stem-cells-mt_roinupb_7L)