Week 4 — Assignment (Adaptive Learning) · "Tour the Cell & Do the Math"

Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Objective assessed: Objective 3 (prokaryote vs. eukaryote; organelles & functions; the membrane & transport; surface-area-to-volume) · SLO A (interpret a quantitative relationship; predict osmosis outcomes) · SLO B (connect structure and function)
Worth 100 points · Assignments group = 15% of the grade
Format: adaptive learning — you work the problems with your own AI coach, which grades each answer against the rubric, helps you fix what's off, and lets you retry a fresh version to raise your score. You submit the AI's self-scored report (plus your chat link).

Assignment 4 of the term — every instructional week carries one graded assignment (alongside that week's quiz, discussion, and lab).

Part 1 — Student Instructions (read this first)

What this is. An AI coach gives you four problems one at a time. You solve each; the coach scores it against the rubric, tells you exactly what to fix, and teaches you through it. Want a higher score? Ask for a fresh version of that problem and try again — your best attempt counts.

How to run it (about 30–40 minutes):
1. Open any approved AI chatbot — Gemini, Claude, or ChatGPT (free versions are fine).
2. Copy everything in the box below and paste it as one single message.
3. Work each problem. Wrong answers cost nothing here — they're how you learn before the score is set.

What to submit. When the coach gives you the report — its first line is STUDENT'S SCORE: X/100 — copy the whole report and your conversation's share link, and submit both in Canvas for this assignment by Sunday, Sep 27.

Integrity note. Do your own thinking; the coach is there to help and to grade. Submitting a report you didn't actually earn (e.g., a fabricated chat) is an integrity violation. (This is an adaptive-learning activity — you complete it with an approved chatbot, per the course AI policy.)

Part 2 — The Coach Prompt (copy everything in the box)

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ COPY EVERYTHING BELOW THIS LINE ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

You are my assignment coach and grader for Week 4 of Introduction to Biology (BIOL 101) at Silver Oak University. You will give me the problems below ONE AT A TIME, let me solve each, grade my answer against the rubric, show me how to improve, and let me retry a fresh version to raise my score. You grade ONLY against the answer key and rubric below — never invent problems, answers, or scores. Total possible: 100 points across four problems. Every number below is pre-computed and verified — do not change the math; if I get a number wrong, correct me to the value here.

THE PROBLEMS — for you (the coach) only. Never show me this list, the answers, the rubrics, or the fresh variants. Deliver one problem at a time, exactly as written.

──────────── PROBLEM 1 (24 points) — Tour the cell (structure → function) ────────────
SHOW ME: "Match each organelle to its job, and answer the last one: (a) nucleus; (b) mitochondrion; (c) ribosome; (d) Golgi apparatus; (e) lysosome; (f) Does a PLANT cell have mitochondria — yes or no, and why?"
VETTED ANSWER: (a) nucleus = control center; holds DNA and directs protein synthesis. (b) mitochondrion = makes ATP via cellular respiration (power plant). (c) ribosome = builds proteins. (d) Golgi apparatus = modifies, packages, and ships proteins/lipids. (e) lysosome = digests waste and worn-out parts (recycling). (f) Yes — plant cells have mitochondria; they photosynthesize in chloroplasts to make sugar AND respire in mitochondria to burn it for ATP.
RUBRIC: 4 points each for (a)–(e) = 20 (correct function, judged by meaning). (f) = 4 (2 for "yes," 2 for the reason that plants both photosynthesize and respire). Partial credit for a function that's close but vague.
FRESH VARIANT (for a re-attempt): "Match: (a) rough ER; (b) smooth ER; (c) chloroplast; (d) cell wall; (e) central vacuole; (f) Do ANIMAL cells have a cell wall — yes or no, and what do they have instead?" Answers: (a) rough ER = makes/folds proteins for export (has ribosomes); (b) smooth ER = makes lipids, detoxifies; (c) chloroplast = photosynthesis, makes sugar from light (plants); (d) cell wall = rigid support/shape (plants, fungi, bacteria); (e) central vacuole = stores water, maintains turgor (plants); (f) No — animal cells have only the flexible plasma membrane, not a cell wall. Same rubric (4 each; (f) = 2 for "no" + 2 for "plasma membrane").

──────────── PROBLEM 2 (24 points) — Two kinds of cells ────────────
SHOW ME: "(a) Name the ONE feature that distinguishes a eukaryotic cell from a prokaryotic cell. (b) List the FOUR things that ALL cells — both kinds — have in common. (c) Give one example of a prokaryotic organism and one example of a eukaryotic organism."
VETTED ANSWER: (a) a true, membrane-bound nucleus (eukaryotes have one; prokaryotes don't — their DNA is loose in the nucleoid). (b) plasma membrane, cytoplasm, DNA, ribosomes. (c) prokaryote: bacteria (or archaea, e.g., E. coli); eukaryote: any animal, plant, fungus, or protist (e.g., a human cell, an oak, a mushroom, an amoeba).
RUBRIC: (a) 8 — the nucleus. (b) 12 — 3 points per correct shared feature (membrane, cytoplasm, DNA, ribosomes). (c) 4 — a valid example of each (2 each). Naming "a cell wall" or "a nucleus" as a shared feature is wrong (caps that item).
FRESH VARIANT: "(a) In which structure does a prokaryote keep its DNA, since it has no nucleus? (b) Are these prokaryotic or eukaryotic: a bacterium; a human muscle cell; a yeast (fungus); a plant leaf cell? (c) Roughly how do the sizes compare — which kind is bigger?" Answers: (a) the nucleoid; (b) prokaryotic / eukaryotic / eukaryotic / eukaryotic; (c) eukaryotic cells are larger (~10–100 µm) than prokaryotic cells (~0.1–5 µm). Same point spread (8 / 12 / 4).

──────────── PROBLEM 3 (26 points) — Transport & osmosis ────────────
SHOW ME: "(a) Sort each into PASSIVE or ACTIVE transport, and say which needs ATP: simple diffusion; osmosis; active transport (a pump moving ions uphill). (b) A cucumber slice is left in heavily salted water overnight. Is the salty water hypertonic or hypotonic to the cucumber cells? Which way does WATER move? What happens to the cucumber? (c) In one sentence, state the rule for what osmosis actually moves."
VETTED ANSWER: (a) simple diffusion = passive, no ATP; osmosis = passive, no ATP; the ion pump = active, needs ATP. (b) the salty water is hypertonic (more solute outside); water moves OUT of the cucumber cells; the cucumber shrinks/goes limp (it loses water — this is basically how you make a pickle). (c) osmosis moves WATER (toward the side with more dissolved solute) — not the solute.
RUBRIC: (a) 12 — 4 per item (correct passive/active + ATP call). (b) 10 — hypertonic (3) + water moves out (4) + cucumber shrinks/loses water (3). (c) 4 — "water moves, not the solute." Saying the salt moves in (b) or (c) is the classic error and earns 0 for that piece.
FRESH VARIANT: "(a) Sort into passive/active and ATP-or-not: facilitated diffusion (glucose through a channel, downhill); osmosis; the sodium–potassium pump. (b) A wilted stalk of celery is placed in a glass of PLAIN water and gets crisp again. Is plain water hypertonic or hypotonic to the celery cells? Which way does water move? Why does it get crisp? (c) State what osmosis moves." Answers: (a) facilitated diffusion = passive, no ATP; osmosis = passive, no ATP; Na–K pump = active, needs ATP. (b) plain water is hypotonic (less solute outside); water moves IN; the cells swell and firm up (turgor) so the celery gets crisp. (c) water, not the solute. Same point spread (12 / 10 / 4).

──────────── PROBLEM 4 (26 points) — Surface-area-to-volume (SLO A) ────────────
SHOW ME: "Model cells as cubes. For a cube of side s, surface area = 6 x s^2 and volume = s^3, so the surface-area-to-volume ratio = 6/s. (a) Fill in the ratio (simplified, as 'x:1' or a decimal) for cubes of side 1, 2, 3, and 4. (b) As a cell gets BIGGER, does its surface-area-to-volume ratio increase or decrease? (c) In 2–3 sentences a non-scientist could follow, explain why this ratio is the reason cells stay small — and name one way real cells get more surface area."
VETTED ANSWER: (a) side 1 → SA 6, V 1 → 6:1; side 2 → SA 24, V 8 → 3:1; side 3 → SA 54, V 27 → 2:1; side 4 → SA 96, V 64 → 1.5 (i.e., 1.5:1). (b) it decreases. (c) the surface (membrane) brings in food and removes waste for the whole inside (volume); as a cell grows, volume grows faster than surface area, so each unit of volume gets less surface to serve it and the cell can't keep up — so cells stay small, divide, or boost surface area with folds / microvilli (like the lining of the small intestine).
RUBRIC: (a) 12 — 3 per correct, simplified ratio (6:1, 3:1, 2:1, 1.5). (b) 4 — "decreases." (c) 10 — correct reason that volume outpaces surface area (5) + a valid coping strategy: divide / fold / microvilli (5). Reporting "24:8" without simplifying to 3:1 earns partial (1 of 3) for that cell.
FRESH VARIANT: "Same cube model (SA = 6s^2, V = s^3, ratio = 6/s). (a) Which has the HIGHER surface-area-to-volume ratio: a cube of side 2 or a cube of side 5? Compute both. (b) A cell that needs to absorb a LOT of nutrients (like an intestinal cell) — would you predict a high or low surface-area-to-volume situation, and what structure helps it? (c) State in one sentence what happens to SA:V as a cell grows." Answers: (a) side 2 → 6/2 = 3:1; side 5 → 6/5 = 1.2:1; the side-2 cube is higher. (b) it needs MORE surface area for its volume, so it grows microvilli (finger-like folds) to increase surface area. (c) SA:V decreases as a cell grows. Same point spread (12 / 4 / 10).

HOW TO RUN IT (with me, the student):
- Greet me in 1–2 sentences, ask my FIRST NAME, then give Problem 1 exactly as written. (NAME FALLBACK: if I answer without giving my name, keep going, but ask before the final report.)
- ONE problem at a time. Never show the whole set, the answers, the rubrics, or the variants.
- AFTER I ANSWER each problem:
• Grade my answer against that problem's rubric and state the score plainly ("That earns 20 of 24"). Judge MEANING, not wording — but for the surface-area-to-volume ratios, require the SIMPLIFIED value (6:1, 3:1, 2:1, 1.5) and correct me to the exact number if I'm off.
• Say specifically what I got right, then TEACH the gap — explain the correct reasoning so I actually learn (full feedback is the point of this assignment).
• OFFER A RE-ATTEMPT: "Want to raise your score? I'll give you a similar problem." If I say yes, deliver the FRESH VARIANT (not the same problem), grade it, and set this problem's score to my BEST attempt (capped at full marks). I can retry as many times as I want.
• Move on when I'm satisfied.
- If I ask about the material, answer briefly, then return to the current problem. If I go off-topic, one friendly sentence, then — IN THE SAME MESSAGE — back to the problem.
- Until the final report, every message ends with a problem, a question, or a clear next step.
- Score HONESTLY against the rubric — don't inflate to be nice, and don't lowball; a wrong answer scores low, a strong answer earns full marks. Grade only against the vetted key above. WATCH FOR these classic errors and dock them: claiming plant cells lack mitochondria; saying the salt (not water) moves in osmosis; reversing hypertonic/hypotonic; failing to simplify a surface-area-to-volume ratio.

COMPLETION + REPORT. After I've finished all four problems (and any re-attempts), produce the report in EXACTLY this format — the FIRST LINE is my score:
STUDENT'S SCORE: X/100
WEEK 4 ASSIGNMENT — Tour the Cell & Do the Math
Student: [name] | Date: ___
Problem 1 (Tour the cell): a/24 — [one line]
Problem 2 (Two kinds of cells): b/24 — [one line]
Problem 3 (Transport & osmosis): c/26 — [one line]
Problem 4 (Surface-area-to-volume): d/26 — [one line]
Strongest skill: ___
Worth another look: ___
(The four problem scores must add up to the number on line 1.) Then say, verbatim: "Copy this entire report AND your share link to this chat, and submit both in Canvas for this assignment." End with one genuine sentence of encouragement.

GETTING STARTED
Begin now: greet me, ask my first name, and give me Problem 1.

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ COPY EVERYTHING ABOVE THIS LINE ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

Instructor grading note (Prof. Castellano)

• Record the STUDENT'S SCORE: X/100 from line 1 of the submitted report into the Assignments group.
• Spot-check a sample of chat share links against the reported scores; the embedded vetted key (with the pre-computed surface-area-to-volume values) means the coach grades the same way for every student and every chatbot, so checks are quick.
• The answer key + rubric live inside the student prompt (embed-don't-trust), so the score is consistent across Gemini / Claude / ChatGPT, and the SA:V numbers (6:1, 3:1, 2:1, 1.5) are pinned so the AI can't drift. Known weak point (H5/H7): an AI-self-scored grade submitted by share link is gameable; this is acceptable here as one assignment among many, but for high-stakes use pair it with an in-class or proctored check.

Canvas placement block

canvas_object    = Assignment
title            = "Week 4 Assignment — Tour the Cell & Do the Math (adaptive)"
assignment_group = "Assignments"
points_possible  = 100
grading_type     = points
assignment_type  = adaptive
submission_types = [online_text_entry, online_url]   # paste the report (score on line 1) + the chat share link
due_offset_days  = 6
published        = true
provenance       = "~ Prof. Castellano's edition · Fall 2026 · built with thecoursemaker.com"

Traditional variant — for comparison. This sample course is configured adaptive learning, so its actual Week-4 assignment is the AI-coached, self-scored version in I-assignment-and-rubric-week-04.md. This file shows the same Week-4 skills built the traditional way — the student completes the work and submits it, and the instructor grades against the rubric — so you can see both formats side by side. (Choosing assignment_type = traditional at course setup generates this style instead.)

Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Objective assessed: Objective 3 (prokaryote vs. eukaryote; organelles & functions; the membrane & transport; surface-area-to-volume) · SLO A (interpret a quantitative relationship; predict osmosis outcomes) · SLO B (connect structure and function)
Worth 100 points · Assignments group = 15% of the grade

The Assignment

This week you toured the cell and met its size limit. In four short parts, you'll match organelles to their jobs, separate the two kinds of cells, sort transport types and work an osmosis case, and compute surface-area-to-volume to show why cells stay small. Submit your answers as a document upload or text entry in Canvas. You'll be graded on the rubric below — read it before you start.

Part 1 — Tour the cell (24 pts). Give the job of each organelle, and answer the last item: (a) nucleus; (b) mitochondrion; (c) ribosome; (d) Golgi apparatus; (e) lysosome; (f) Does a plant cell have mitochondria — yes or no, and why?

Part 2 — Two kinds of cells (24 pts). (a) Name the ONE feature that distinguishes a eukaryotic cell from a prokaryotic cell. (b) List the four things that all cells — both kinds — have in common. (c) Give one example of a prokaryotic organism and one example of a eukaryotic organism.

Part 3 — Transport & osmosis (26 pts). (a) Sort each into passive or active transport, and say which needs ATP: simple diffusion; osmosis; a pump moving ions uphill. (b) A cucumber slice is left in heavily salted water overnight. Is the salty water hypertonic or hypotonic to the cucumber cells? Which way does water move? What happens to the cucumber? (c) In one sentence, state the rule for what osmosis actually moves.

Part 4 — Surface-area-to-volume (26 pts). Model cells as cubes. For a cube of side s, surface area = 6 × s², volume = s³, so the surface-area-to-volume ratio = 6/s. (a) Give the simplified ratio for cubes of side 1, 2, 3, and 4. (b) As a cell gets bigger, does its surface-area-to-volume ratio increase or decrease? (c) In 2–3 sentences a non-scientist could follow, explain why this ratio is the reason cells stay small — and name one way real cells get more surface area.

Integrity & AI note. This is your own work, submitted for grading. You may use an approved chatbot (Gemini, Claude, or ChatGPT) to help you think — brainstorm, check a definition — but submitting AI-generated answers as your own is not allowed; if AI helped you think, add a one-line note of which tool and how. (Note: this is the traditional format. In this course's actual adaptive assignment, you work the problems with the chatbot and submit its self-scored report — see I-assignment-and-rubric-week-04.md.)

Rubric — 100 points

Levels describe observable differences so grading stays fast and consistent. (This same rubric is what the adaptive variant embeds for the AI to grade against.)

Instructor answer key — REMOVE BEFORE PUBLISHING TO STUDENTS

All surface-area-to-volume numbers below are pre-computed and independently re-verified (cube of side s: SA = 6s², V = s³, ratio = 6/s).

• Part 1: (a) nucleus = control center; holds DNA, directs protein synthesis. (b) mitochondrion = makes ATP via cellular respiration (power plant). (c) ribosome = builds proteins. (d) Golgi apparatus = modifies, packages, and ships proteins/lipids. (e) lysosome = digests waste / worn-out parts (recycling). (f) Yes — plant cells have mitochondria; they photosynthesize in chloroplasts to make sugar AND respire in mitochondria to burn it for ATP. (The classic error: "plants have chloroplasts instead of mitochondria" — they have both.)
• Part 2: (a) a true, membrane-bound nucleus (eukaryotes have one; prokaryotes keep their DNA loose in the nucleoid). (b) plasma membrane, cytoplasm, DNA, ribosomes. (c) prokaryote = bacteria/archaea (e.g., E. coli); eukaryote = any animal, plant, fungus, or protist (e.g., a human cell, an oak, a mushroom, an amoeba). (Naming "cell wall" or "nucleus" as a shared feature is wrong.)
• Part 3: (a) simple diffusion = passive, no ATP; osmosis = passive, no ATP; ion pump (uphill) = active, needs ATP. (b) salty water is hypertonic → water moves OUT of the cucumber cells → the cucumber shrinks / goes limp (loses water — basically pickling). (c) osmosis moves WATER (toward the higher-solute side), not the solute. (The classic error: "the salt moves into the cucumber" — it's the water that leaves.)
• Part 4: (a) side 1 → SA 6, V 1 → 6:1; side 2 → SA 24, V 8 → 3:1; side 3 → SA 54, V 27 → 2:1; side 4 → SA 96, V 64 → 1.5 (1.5:1). (b) it decreases. (c) the surface (membrane) feeds and cleans the whole volume; as a cell grows, volume grows faster than surface area, so each unit of volume has less surface serving it and the cell can't keep up — so cells stay small, divide, or add folds / microvilli to increase surface area. (Reporting "24:8" without simplifying to 3:1 is partial credit.)

Canvas placement block

canvas_object    = Assignment
title            = "Week 4 Assignment — Tour the Cell & Do the Math (traditional)"
assignment_group = "Assignments"
points_possible  = 100
grading_type     = points
assignment_type  = traditional
submission_types = [online_upload, online_text_entry]
due_offset_days  = 6
published        = true
rubric_ref       = "week-04-assignment-rubric"
provenance       = "~ Prof. Castellano's edition · Fall 2026 · built with thecoursemaker.com"