Week 5 — Reading an Enzyme Experiment: The Catalase Lab Report

Assignment 5 of the term — read an enzyme experiment from its numbers to its conclusion and explain it to someone new to biology.

This adaptive assignment uses a coaching dialogue to help you turn a first attempt into a clear, evidence-based lab report. You remain the author. The coach asks questions, checks the reasoning you show, and waits for you to revise before it produces the required report. This week's lecture tutorial, quiz, discussion, and Biology Lab & Inquiry practise the same ideas from other angles; this assignment is where you put them together on one small enzyme experiment. It builds on Week 1's controlled experiment and Week 3's idea that a protein's shape is its job.

The task

Pieces of potato were held at four temperatures, dropped into hydrogen peroxide, and the foam height was measured after 60 seconds. Catalase in the potato splits hydrogen peroxide into water and oxygen, and the oxygen makes the foam. The catalase and temperature example is an illustrative dataset constructed for this course (not real data). Three trials were run at each temperature:

• cold, about 5 °C: 1, 2, and 3 cm;
• room, about 22 °C: 4, 5, and 6 cm;
• body, about 37 °C: 9, 10, and 11 cm;
• boiled, about 100 °C and cooled before testing: 0, 0, and 0 cm.

The averages are 2 cm cold, 5 cm room, 10 cm body, and 0 cm boiled.

Work these four problems, showing your arithmetic:

1. Add the three body-temperature trials from the catalase and temperature example (9, 10, and 11 cm of foam). What is the total, in centimeters?
2. The three cold trials total 6 cm of foam. Divide by the number of trials (3). What is the cold average, in centimeters?
3. The body-temperature average is 10 cm and the cold average is 2 cm. How many times the cold foam is the body-temperature foam?
4. The largest body-temperature trial made 11 cm of foam and the smallest made 9 cm. What is the range of the body-temperature trials, in centimeters?

Beside each answer, add one brief interpretation:

• Problem 1: name the independent variable and the dependent variable, and explain why the experiment runs three trials per condition instead of one.
• Problem 2: explain why the cold sample was slowed rather than denatured, and predict what would happen to its foam if the cold potato were warmed back up.
• Problem 3: explain which temperature sits nearest the enzyme's optimum and why the boiled average of 0 cm shows that hotter is not always faster, and name one controlled variable the design must hold steady.
• Problem 4: compare the spread of the trials with the climb of the averages from 2 to 10 cm, then write a one-sentence conclusion that uses "supports" or "fails to support" rather than "proves," and name one result that would have counted against the hypothesis.

Explain it to a non-expert

Your younger cousin watches the boiled potato sit in the peroxide without a single bubble and asks, "Did the boiling kill the fizz, or did it get too cold afterward?" Write a 3–5 sentence message that explains what the test changed and what it measured, reports the result in everyday words, and names one limit, including that these numbers are illustrative and that one small test can support a claim but never prove it. Explain any technical term in everyday words. More than one good answer is possible.

For a different, ungraded example, imagine a cyclist who tests whether a lighter wheel shortens a daily ride. Model answer: "I rode the same route on calm mornings, changing only the wheel, and timed each ride. The rides with the lighter wheel were a little quicker each time. Everything else about the ride stayed the same, so the wheel is the likely reason. I only tried it a handful of times, so the result supports the idea but does not prove it; a windy week might change things."

Use that pattern for the catalase experiment, with your own wording and evidence.

Part 1 — Student instructions

1. Draft all four answers, the four brief interpretations, and your message to your cousin before opening a chatbot.
2. Open any course-approved chatbot. Copy the entire Coach Prompt box, including its first and last marker lines, and paste it as one message. The coach will ask for your draft and then work one question at a time.
3. Answer in your own words. Show calculations when asked. Use the coach's feedback to revise at least one calculation or explanation, even if your first attempt was correct.
4. Continue until the prompt's exit condition is met.
5. Save the chat's share link and copy the final report exactly as the coach gives it.

The chatbot is a coach, not a ghostwriter. It must draw out your reasoning rather than write the report for you.

Coach Prompt

COPY EVERYTHING BELOW THIS LINE
ROLE: You are a careful learning coach for an introductory biology course. Draw out and challenge MY thinking about reading an enzyme experiment. Do not write my assignment for me, do not invent work I did not show, and never invent a measurement, a study, or a percentage.

ASSIGNMENT: Work through these four problems in order, one at a time. Do not invent, replace, or reorder a problem. The data: the catalase and temperature example, an illustrative dataset constructed for this course (not real data). Potato catalase splits hydrogen peroxide into water and oxygen, and the oxygen makes foam; foam height was measured after 60 seconds, three trials each. Cold (about 5 degrees C): 1, 2, 3 cm. Room (about 22 degrees C): 4, 5, 6 cm. Body (about 37 degrees C): 9, 10, 11 cm. Boiled (about 100 degrees C, cooled before testing): 0, 0, 0 cm. The averages are 2 cm cold, 5 cm room, 10 cm body, and 0 cm boiled.
PROBLEM P1: Add the three body-temperature trials from the catalase and temperature example (9, 10, and 11 cm of foam). What is the total, in centimeters?
PROBLEM P2: The three cold trials total 6 cm of foam. Divide by the number of trials (3). What is the cold average, in centimeters?
PROBLEM P3: The body-temperature average is 10 cm and the cold average is 2 cm. How many times the cold foam is the body-temperature foam?
PROBLEM P4: The largest body-temperature trial made 11 cm of foam and the smallest made 9 cm. What is the range of the body-temperature trials, in centimeters?
After the four answers, I must briefly interpret each one: for P1, the independent and dependent variables and why there are three trials per condition; for P2, why the cold sample was slowed rather than denatured and what warming it would do; for P3, which temperature sits nearest the optimum, why the boiled zero shows hotter is not always faster, and one controlled variable the design must hold steady; for P4, the spread of the trials against the climb of the averages, a one-sentence conclusion that uses supports or fails to support rather than proves, and one result that would have counted against the hypothesis. I must then write a 3-5 sentence message to my cousin explaining what the test changed and measured, the result in everyday words, and one limit, including that the numbers are illustrative and that one small test supports but never proves a claim. I must explain technical terms in everyday words.

SCORING CRITERIA: Score only evidence I supply: correct computations (40 points), biological reasoning (32 points), clarity for a non-expert reader (16 points), and showing work so it can be checked (12 points). For each of P1-P4, give 2, 1, or 0 evidence units per criterion; one unit is worth 5 computation points, 4 reasoning points, 2 clarity points, or 1.5 showing-work points. Sum all four problems within each criterion. Count my cousin message only with P4, not again with P1-P3.
COMPUTATION UNITS: A correct total, average, comparison, or range = 2; the right values and operation with only an arithmetic slip = 1; a missing result or the wrong values or operation = 0. Do not penalize an alternative valid method or equivalent correct notation.
REASONING UNITS: For P1-P3 separately, an interpretation that meets both parts named for that problem = 2; exactly one part = 1; neither = 0. For P4, BOTH a conclusion that compares the spread with the climb of the averages and uses supports or fails to support AND a cousin message with the result in everyday words and a named limit = 2. If full P4 evidence is absent but at least one accurate substantive part appears, give 1. No accurate reasoning = 0; calling the cold sample denatured, calling the boiled sample merely slowed, saying hotter is always faster, swapping the independent and dependent variables, or saying the data prove the hypothesis is not accurate. An arithmetic slip alone is not a reasoning error.
CLARITY UNITS: For each problem, labeled evidence understandable to someone new to biology, with technical terms explained = 2; intelligible evidence that needs rereading because of ambiguity or jargon = 1; absent or unintelligible evidence = 0. Include the cousin message with P4 if submitted. Missing reasoning alone does not lower clarity for otherwise clear submitted work.
SHOWING-WORK UNITS: For each problem, checkable values and steps = 2; a relevant but incomplete value or step = 1; a result alone or no method = 0. A visible method stays checkable despite an arithmetic slip.

Do NOT invent grading rules.

DIALOGUE RULES: Ask exactly one question per message and wait for my answer. Start by asking for my complete first attempt. Build each next question from my exact words. Probe an unsupported claim and ask me to examine its evidence. Keep the conversation focused on questions rather than completed work.

ENGAGEMENT GUARDS: A greeting, copied prompt, yes/no reply, or one-word answer is not a substantive exchange. Do not flatter or accept agreement as evidence. Praise only a concrete move I made. If evidence is missing, say what is missing and ask for it. Require a real revision plus a short reflection on why the revision is better. Do not issue the report early.

EXIT CONDITION: Continue until at least five substantive exchanges have occurred AND I have supplied all four answers and their brief interpretations AND written my message to my cousin AND revised at least one calculation or explanation AND reflected on the revision. Stop only after whichever requirement happens last.

REPORT: After the exit condition is satisfied, output exactly these labelled lines in this order. Replace X with the exact earned score; it may end in .5 and must not be rounded to a whole number. Base every line only on evidence in this chat; write "Not supplied" for missing evidence and never raise the score for polished chatbot prose.
STUDENT'S SCORE: X/100
EVIDENCE FOR THE SCORE: [specific evidence from my calculations and reasoning]
REVISION MADE: [what I changed and why]
STRENGTH: [one earned strength]
NEXT STEP: [one concrete improvement]
Then tell me to submit this report, my revised lab report, and the share link.
COPY EVERYTHING ABOVE THIS LINE

Deliverables

Submit these three items in the assignment entry:

• your revised lab report with all four answers, their brief interpretations, and your message to your cousin — written, or recorded as audio or video with a transcript, or as a labelled sketch of the four averages with a short note; every form is graded by the same scoring criteria;
• the coach's five-line report; and
• the conversation share link.

Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text.

Equivalent route (no AI required)

This route assesses the same Week 5 skills — reading an enzyme experiment as a controlled test, computing a total, an average, a comparison, and a range with every step shown, telling a slowed enzyme from a denatured one, and stating an honest conclusion — for comparable time and effort, about 60 to 90 minutes, the same as the coached route. Complete the same four problems, the four brief interpretations, and the message to your cousin. Then audit your own first draft against the attached scoring criteria, criterion by criterion, and write a second draft. Add a 150–200 word revision memo that names one calculation or explanation you changed, the evidence that prompted the change, and one question you still have. Submit the revised lab report, your completed criteria checklist, and the revision memo in the assignment entry; together they replace the share link and the coach's report. This route uses the same scoring criteria and the same points, with no penalty for choosing it.

How you'll be graded

The full analytic rubric is attached to this assignment in Canvas.

Academic integrity and AI use

The calculations, reasoning, revision, and final report must be your own. Do not ask the chatbot to create the assignment or add evidence you did not produce. Submit an honest share link from your own dialogue. The equivalent route keeps the same workload and evidence and requires no AI account.

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