Week 14 — Quiz (auto-graded) · Gene Expression

Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Objective tested: Objective 7 — the central dogma; transcription (DNA → mRNA; U not T); the genetic code (codons, AUG start, the three stop codons); translation (ribosome, tRNA, in the cytoplasm).
Points: 10 (1 each) · Assignment group: Quizzes (10% of grade) · Due: end of Module 14.

This is the human-readable quiz with its vetted answer key and feedback. The import-ready Classic QTI is in F-quiz-week-14-qti.xml (generated by the shared validated script — parses with 10 items, every single-answer item exactly one correct). The reusable item-bank entries and the Canvas placement block are at the bottom of this file.

Blueprint

No trick questions; distractors target the Week 14 misconceptions named in the lecture outline (T in RNA; transcription vs. translation; wrong reading frame; anticodon location; translation location). The one translation item provides the codon table in its stem so it stays auto-gradable.

Questions, key, and feedback

Q1 (MC). The central dogma of molecular biology describes how genetic information flows in a cell. Which sequence shows that flow correctly?
- A. protein → RNA → DNA
- B. DNA → RNA → protein ✅
- C. RNA → DNA → protein
- D. DNA → protein → RNA
Feedback: Information flows DNA → RNA → protein. DNA is copied into mRNA (transcription), and the mRNA is read to build a protein (translation). (A reverses it; C and D scramble the order.)

Q2 (MC). During transcription, the cell copies a DNA template strand into mRNA. A T in the DNA template pairs with which base in the new mRNA?
- A. A (adenine) ✅
- B. T (thymine)
- C. U (uracil)
- D. G (guanine)
Feedback: A template T pairs with A in the mRNA, just like in DNA. (The famous swap goes the other way: where DNA has an A, the mRNA gets a U — because RNA uses uracil instead of thymine.)

Q3 (Multiple answer — select all that apply). Which of the following statements about RNA and transcription are true?
- A. mRNA uses the base uracil (U) in place of thymine (T) ✅
- B. mRNA contains thymine (T) just like DNA does
- C. Transcription copies a gene's DNA into a messenger RNA (mRNA) ✅
- D. Transcription takes place in the nucleus ✅
- E. mRNA is double-stranded, exactly like DNA
Feedback: mRNA uses U (not T), it is the product of transcription (DNA → mRNA), and transcription occurs in the nucleus. B is false (no T in RNA), and E is false (mRNA is single-stranded — it's a copy of one DNA strand).

Q4 (MC). Almost every protein begins with the same start codon, which also codes for the amino acid methionine and sets the reading frame. That start codon is —
- A. UAA
- B. UGA
- C. AUG ✅
- D. GCU
Feedback: AUG is the start codon; it codes for methionine (Met) and tells the ribosome where to begin reading in threes. (UAA and UGA are stop codons; GCU is an ordinary amino-acid codon.)

Q5 (MC). Which of the following is one of the three stop codons — a codon that ends the protein and codes for no amino acid?
- A. AUG
- B. GCU
- C. UGA ✅
- D. UAU
Feedback: The three stop codons are UAA, UAG, and UGA. UGA is one of them. (AUG is the start codon; GCU = alanine and UAU = tyrosine are ordinary codons.)

Q6 (Matching). Match each central-dogma term to its correct description.
| Term | Correct description |
|---|---|
| Transcription | Copying DNA into mRNA, in the nucleus |
| Translation | Reading mRNA to build a protein, in the cytoplasm |
| Codon | A three-base unit of mRNA that codes for one amino acid |
| Ribosome | The machine that reads the mRNA and assembles the protein |
Feedback: The classic mix-ups: transcription writes the message (DNA → mRNA, nucleus) while translation reads it (mRNA → protein, cytoplasm); a codon is three mRNA bases for one amino acid; the ribosome is the machine that does the reading and assembling.

Q7 (MC). Use this codon table: AUG = Methionine (Met), GCU = Alanine (Ala), UAU = Tyrosine (Tyr), UGA = STOP. An mRNA reads 5′-AUG GCU UAU UGA-3′. The protein it codes for is —
- A. Met – Ala – Tyr – Stop (a four-amino-acid protein ending in "Stop")
- B. Met – Ala – Tyr ✅
- C. Tyr – Ala – Met
- D. Ala – Tyr – Met – Ala
Feedback: Read in threes from the start: AUG→Met, GCU→Ala, UAU→Tyr, UGA→STOP. The stop codon ends translation and is not an amino acid, so the protein is Met–Ala–Tyr. (A wrongly lists "Stop" as an amino acid; C reverses the order; D invents extra residues.)

Q8 (True / False). "Translation — the building of a protein at the ribosome — takes place inside the nucleus."
- True
- False ✅
Feedback: False. Transcription happens in the nucleus, but the mRNA then travels out, and translation happens in the cytoplasm, at the ribosome.

Q9 (MC). An mRNA carries a codon. The complementary three-base sequence that pairs with that codon is the anticodon. Where is the anticodon located?
- A. on the mRNA, right next to the codon
- B. on the DNA template strand
- C. on the tRNA (transfer RNA) ✅
- D. built into the ribosome itself
Feedback: The codon is on the mRNA; the anticodon is on the tRNA, which base-pairs with the codon and delivers the matching amino acid. (Saying the anticodon is on the mRNA is the classic error.)

Q10 (MC). One key difference between DNA and RNA is in their bases. DNA uses A, T, G, and C. Which base does RNA use in place of thymine (T)?
- A. adenine (A)
- B. uracil (U) ✅
- C. guanine (G)
- D. cytosine (C)
Feedback: RNA uses uracil (U) wherever DNA would use thymine (T). There is no T in RNA — a stray T in your mRNA is the most common transcription error.

Answer key (quick reference)

Quality gate (self-checked): each single-answer item has exactly one correct option; the multiple-answer item (Q3) lists all three true statements (A, C, D) and requires B and E to be left unselected; the matching item (Q6) pairs four terms to four distinct descriptions; no item asserts a fact outside the Week 14 course definitions. The one sequence item (Q7) supplies its codon table in the stem so it is fully auto-gradable. Quantitative gate: PASS — the deterministic translation in Q7 was re-derived by an independent Python check: DNA template 3′-TAC CGA ATA ACT-5′ → mRNA 5′-AUG GCU UAU UGA-3′ → AUG=Met, GCU=Ala, UAU=Tyr, UGA=STOP → protein Met–Ala–Tyr (the three stop codons {UAA, UAG, UGA} and the start codon AUG=Met were verified against the standard genetic code, 0 errors).

Item-bank entries (for variants + the midterm/final)

All ten items are tagged course=BIOL101 · week=14 · objective=7 · topic=gene-expression and deposited in Item Bank: Week 14 — Gene Expression. The final (Week 16) and the per-term variant updates draw fresh items from this bank. (Tags: q1 central-dogma, q2 transcription-pairing, q3 rna-transcription-facts, q4 start-codon, q5 stop-codon, q6 dogma-terms-match, q7 translate-sequence, q8 translation-location, q9 codon-vs-anticodon, q10 u-not-t.)

Canvas placement block

canvas_object   = Quizzes::Quiz
title           = "Week 14 Quiz — Gene Expression"
assignment_group = "Quizzes"
points_possible = 10
grading_type    = points
due_offset_days = 6        # 6 days after module start
published       = true
shuffle_answers = true
provenance      = "~ Prof. Castellano's edition · Fall 2026 · built with thecoursemaker.com"