Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Module: Week 15 of 16 · Fall 2026 · in-person, two 75-minute lectures + one weekly lab
Objective covered: Objective 8 — Explain how gene expression is regulated, describe the major types of mutations and their effects, and describe the core tools of biotechnology (PCR, gel electrophoresis, recombinant DNA, and CRISPR).

This file holds two pieces: (A) the Module 15 Overview page ("Start Here") and (B) the Welcome Announcement that drips out when the module opens. Dates below assume a Tuesday/Thursday lecture pattern with Week 15 meeting Tue Dec 8 and Thu Dec 10, a lab that same week, and end-of-week work due Sunday Dec 13, 11:59 p.m. This is the last instructional week before the final (Week 16). Adjust the day-of-week and times to match your section.

(A) Module 15 Overview — Start Here

Welcome to Week 15: Gene Regulation, Mutation & Biotechnology

This is your home base for the week. Read it first, then work the checklist below from top to bottom. Everything you need is linked inside the module.

This is the final new-material week of the course, and it's the one where two semesters of molecular biology pay off in the real world. You already know the central dogma — DNA → RNA → protein (Weeks 13–14). Now we answer three questions that turn that knowledge into power: if every cell has the same DNA, why isn't every cell the same? (gene regulation), what happens when the DNA gets a typo? (mutation), and how do scientists actually read, copy, and edit DNA? (biotechnology — PCR, gel electrophoresis, recombinant DNA, and CRISPR). By Friday you'll connect a single DNA change to a trait, sort the tools that copy DNA from the tools that sort it, and take a real position in the term's biggest ethical debate: should we edit the human genome?

The week's big question

"If every cell carries the same DNA, why are they different — and now that we can read, copy, and edit that DNA, what should we do with it?"

By Friday you'll be able to explain why cells switch genes on and off, classify the major mutation types by their effect, describe what PCR and gel electrophoresis each do, and reason carefully about the ethics of gene editing.

By the end of this week, you can…

Use this as a checklist. If you can do all four out loud, you're ready for the quiz.

• [ ] Explain gene regulation — why a cell expresses only some of its genes, using the lac operon as the classic on/off switch — and bust the myth that "you use all your genes all the time."
• [ ] Classify mutations by effect — point mutations (silent, missense, nonsense) and frameshift (insertion/deletion) — and explain why mutations can be harmful, neutral, or beneficial (the raw material for evolution).
• [ ] Describe the biotechnology toolkit — PCR copies DNA, gel electrophoresis sorts DNA by size (smaller fragments travel farther), recombinant DNA/plasmids combine DNA from different sources, and CRISPR edits DNA.
• [ ] Reason about gene-editing ethics — take and defend a position on a genuine socio-scientific question (editing human embryos, GMOs, or DNA fingerprinting in court).

What's due this week, and when

Work these in order — each one gets you ready for the next.

Heads-up on the AI tools: you'll use a chatbot to draft and explain, and then you judge its work against what we cover in class. This week the model loves to claim that bigger DNA fragments travel farther in a gel (they travel less far), to confuse PCR with gel electrophoresis (one copies, one sorts), and to say all mutations are harmful (many are neutral or even helpful). Catching the model is the point — in the tutorial, the assignment, and the lab.

Late policy reminder: 10% off per day late. This is the last graded week before the final, so don't let anything slip — if life happens, reach out before the deadline. I'd much rather hear from you early.

How to succeed this week

• Lead with the idea, not the jargon. Gene regulation is just a cell deciding which recipes to cook tonight; a mutation is just a typo in the recipe; the biotech tools are just ways to photocopy, sort, splice, and edit a text.
• Memorize three tiny hooks. "Same DNA, different genes ON." "PCR copies; the gel sorts." And the gel rule: "Small and fast runs far."
• Build the mutation chain. For one base change, trace it: DNA → mRNA codon → amino acid → protein → trait. Whether it's silent, missense, or nonsense depends on what happens at the amino acid step.
• Come ready to argue — for real. This week's discussion is the most arguable of the whole term. There's no "correct" answer to hand in; there's a defensible one. Pick a side on gene editing and be ready to defend it and to steelman the other side.
• Treat the chatbot as a smart intern, not an oracle. It drafts; you check. That habit is the whole semester in miniature — and it's exactly what the final will reward.

This is the capstone of the molecular arc. Next week is the final (Week 16), which is cumulative — so this week also doubles as your launchpad into review. Come to class Tuesday ready to debate whether we should edit a human embryo to remove a disease. See you Tuesday.

(B) Welcome Announcement — Module 15

Release setting: post on the module's start day (offset = 0 days), i.e., Tue Dec 8, 2026 — not before. If your platform won't preserve the scheduled date on import, post this as a draft labeled "Release: Tue Dec 8."

Subject: Week 15 — should we edit the human genome? 🧬

Hi everyone, and welcome to our last week of new material!

Quick warm-up before we start: a couple knows their future child has a 1-in-4 chance of inheriting a fatal genetic disease. A new tool could edit the embryo and remove that gene forever — from the child and all of their descendants. Should they be allowed to? That tool, CRISPR, is real, and that exact scenario has already happened once. There's no easy answer — and that's the point. This week you'll have the science to reason about it instead of just reacting to it.

This week — Gene Regulation, Mutation & Biotechnology — we tackle the big question: If every cell has the same DNA, why are cells different — and now that we can read, copy, and edit DNA, what should we do with it? By Friday you'll explain why genes switch on and off, sort the mutations that are harmless from the ones that aren't, and describe the tools (PCR, gel electrophoresis, recombinant DNA, CRISPR) that built modern biology.

Three things not to miss:
1. Lecture Tutorial 15 — work through gene regulation, the mutation types, and the biotech toolkit with one approved chatbot (Gemini, Claude, or ChatGPT) and submit the share link. You'll catch the model's mistakes — it loves to say bigger DNA fragments travel farther in a gel (they don't). Due Sun Dec 13.
2. Lab 15 ("Whose DNA Is It? A Virtual Gel"), Quiz 15, Discussion 15, and Assignment 15 also close Sun Dec 13 — the lab is a free virtual DNA-fingerprinting experiment, and the discussion is the most arguable one of the term, so start early.
3. Open the Start Here page first — it lays out everything in order with due dates, and it flags that next week is the cumulative final.

One promise: by the end of this week, the headlines about "designer babies," GMO labels, and DNA evidence in court will stop being mysterious. You'll have the actual biology — regulation, mutation, and the gene-editing toolkit — to think clearly about the most important questions of our genetic age.

Bring your curiosity (and a real opinion about gene editing) to class on Tuesday.

See you soon,
Prof. Castellano