Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Module: Week 14 of 16 · Fall 2026 · in-person, two 75-minute lectures + one weekly lab
Objective covered: Objective 7 — Explain how the information in DNA is expressed — transcription of DNA into mRNA, the genetic code, and translation of mRNA into protein (the central dogma).

This file holds two pieces: (A) the Module 14 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 14 meeting Tue Dec 1 and Thu Dec 3, a lab that same week, and end-of-week work due Sunday Dec 6, 11:59 p.m. Adjust the day-of-week and times to match your section.

(A) Module 14 Overview — Start Here

Welcome to Week 14: Gene Expression

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.

Last week you learned that DNA is a stable archive that copies itself so every cell carries the same instructions. This week we answer the obvious next question: how does a cell actually use those instructions to build something? A gene is a stretch of DNA, but DNA never leaves the nucleus and ribosomes can't read it directly. So the cell runs a two-step relay — DNA → RNA → protein, the central dogma — copying a gene into a portable mRNA message (transcription) and then reading that message three letters at a time to string together a protein (translation). By Friday you'll be able to take a short DNA sequence and walk it all the way to the protein it encodes, every step shown.

The week's big question

"A gene is just a string of DNA letters — so how does a cell turn those letters into a working protein?"

By Friday you'll be able to lay out the central dogma in order, transcribe a DNA template strand into mRNA (remembering RNA uses U, not T), read codons off the genetic code (including the AUG start and the three stop codons), and translate a sequence into its chain of amino acids.

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.

• [ ] Lay out the central dogma in order — DNA → (transcription) → mRNA → (translation) → protein — and say where each step happens (transcription in the nucleus, translation in the cytoplasm at the ribosome).
• [ ] Transcribe a DNA template strand into mRNA, pairing A–U, T–A, G–C, C–G — remembering RNA carries U instead of T.
• [ ] Read the genetic code — a codon is three mRNA bases; AUG is the start codon (and codes for Methionine); UAA, UAG, and UGA are the three stop codons.
• [ ] Translate an mRNA sequence into a chain of amino acids using a codon table, and explain the roles of the ribosome and tRNA (the tRNA carries the anticodon and brings the matching amino acid).

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. Chatbots routinely put a T in RNA, read codons in the wrong frame, or say translation happens in the nucleus (it's the cytoplasm). Catching the model is the point — in the tutorial, the assignment, and the lab.

Late policy reminder: 10% off per day late. If life happens, reach out before the deadline — I'd much rather hear from you early.

How to succeed this week

• Lead with the relay, not the jargon. The whole week is one sentence: DNA is copied into RNA, and RNA is read to build protein. Everything else (codons, tRNA, start/stop) hangs off that relay. Get the arrow direction first.
• Memorize three tiny hooks. "RNA has U, not T." "AUG starts; UAA/UAG/UGA stop." And "Read in threes, in frame."
• Do one full sequence by hand. Take a DNA template, transcribe it to mRNA, then translate it with the codon table — once, slowly, showing every base. After that the lab and the quiz feel routine.
• Keep transcription and translation straight. Transcription writes a message (DNA → RNA, in the nucleus). Translation reads the message into protein (RNA → protein, in the cytoplasm). Same "trans-" prefix, two different jobs.
• Treat the chatbot as a smart intern, not an oracle. It drafts; you check. A confident chatbot will still slip a T into your RNA or shift the reading frame — catching that is the skill.

You don't need to memorize the whole codon table — we always give it to you. What you do need is the process: copy the strand correctly, group bases into threes from the start codon, and read each codon off the chart. Come to class ready to decode a mystery gene together. See you Tuesday.

(B) Welcome Announcement — Module 14

Release setting: post on the module's start day (offset = 0 days), i.e., Tue Dec 1, 2026 — not before. If your platform won't preserve the scheduled date on import, post this as a draft labeled "Release: Tue Dec 1."

Subject: Week 14 — how a string of DNA letters becomes a protein 🧬

Hi everyone,

A quick puzzle to start: your DNA holds the instructions for every protein in your body, but the DNA never leaves the nucleus, and the ribosomes that actually build proteins sit out in the cytoplasm. So how does the instruction get from the locked archive to the factory floor? The cell uses a messenger. This week we follow that relay end to end — DNA → RNA → protein, the central dogma — and by Friday you'll be able to take a gene and read out the exact protein it makes.

This week — Gene Expression — we tackle the big question: A gene is just a string of DNA letters — so how does a cell turn those letters into a working protein? You'll transcribe DNA into an mRNA message (RNA uses U, not T!), read the genetic code in three-letter codons (AUG starts; UAA/UAG/UGA stop), and translate the message into a chain of amino acids.

Three things not to miss:
1. Lecture Tutorial 14 — work through the central dogma, transcription, the genetic code, and translation with one approved chatbot (Gemini, Claude, or ChatGPT) and submit the share link. You'll catch the model's mistakes — like a sneaky T in the RNA — not just trust it. Due Sun Dec 6.
2. Lab 14 ("Transcribe & Translate a Gene"), Quiz 14, Discussion 14, and Assignment 14 also close Sun Dec 6 — the lab decodes a real gene on a free virtual tool, so start early.
3. Open the Start Here page first — it lays out everything in order with due dates.

One promise: you will not have to memorize the genetic code — we always hand you the codon table. What you'll own by Friday is the method: copy the strand, group from the start codon, read in threes. Once you can take a DNA sequence and walk it all the way to a protein, the most famous idea in molecular biology is yours.

Bring your curiosity (and a pencil — we'll decode a mystery gene live) to class on Tuesday.

See you soon,
Prof. Castellano