Gene Expression: From Gene to Protein | Chapter 17 – Campbell Biology (12th) (Revised)

Last Minute Lecture is a student-run project and is currently funded entirely by students who believe educational resources should remain free and accessible. If Last Minute Lecture has helped you study, please consider supporting the project. ❤️ https://lastminutelecture.com/support/ All chapters are now available for free on our new platform: https://lastminutelecture.com 📚 Chapter 17 of Campbell Biology explains gene expression, the process by which information from a gene is used to synthesize proteins. This chapter covers the central dogma of molecular biology, which outlines the flow of genetic information from DNA to RNA to protein. It explores the processes of transcription and translation, including RNA modifications, mutations, and the impact of mutagens. The chapter also highlights how changes in the genetic code, such as point mutations, can affect protein structure and function, leading to diseases. 🔹 Key Concepts 🔹 The Central Dogma of Molecular Biology The genetic information in DNA is transcribed into mRNA, which is then translated into a polypeptide (protein). Transcription involves the synthesis of RNA from a DNA template. Translation involves decoding the mRNA sequence to synthesize a polypeptide. 🔹 Transcription and Translation ✅ Transcription: The process where RNA polymerase reads DNA and synthesizes an mRNA molecule. In eukaryotes, mRNA undergoes modifications such as the addition of a 5′ cap and a poly-A tail, and splicing to remove introns. Prokaryotes lack a nucleus, so transcription and translation occur simultaneously. ✅ Translation: tRNA molecules bring specific amino acids to ribosomes, where the mRNA codons are translated into a polypeptide sequence. Ribosomes facilitate the attachment of amino acids in the correct order based on mRNA codons. 🔹 The Genetic Code The genetic code consists of codons, which are triplets of nucleotides. 64 codons specify amino acids or signal translation termination (stop codons). Start codon (AUG) initiates translation, while redundancy in the code allows multiple codons to specify the same amino acid. 🔹 Mutations Point mutations involve a change in a single nucleotide pair, which can lead to silent, missense, or nonsense mutations. Frameshift mutations occur when nucleotides are added or deleted, altering the reading frame. Mutations can lead to diseases like sickle-cell anemia, where a single mutation changes an amino acid in hemoglobin. 🔹 CRISPR-Cas9 Gene Editing The CRISPR-Cas9 system allows precise editing of genes to correct mutations and is a potential tool for treating genetic disorders. 📘 Have a book recommendation? Submit your suggestion here: https://forms.gle/y7vQQ6WHoNgKeJmh8 Thank you for being a part of our little Last Minute Lecture family! ⚠️ Disclaimer: These summaries are created for educational and entertainment purposes only. They provide transformative commentary and paraphrased overviews to help students understand key ideas from the referenced textbooks. Last Minute Lecture is not affiliated with, sponsored by, or endorsed by any textbook publisher or author. All textbook titles, names, and cover images—when shown—are used under nominative fair use solely for identification of the work being discussed. Some portions of the writing and narration are generated with AI-assisted tools to enhance accessibility and consistency. While every effort has been made to ensure accuracy, these materials are intended to supplement—not replace—official course readings, lectures, or professional study resources. Always refer to the original textbook and instructor guidance for complete and authoritative information.