This packet is everything a parent or guide needs to assess Unit 03 at home — learning targets, the answers that count as correct, the mastery rubric, calibration examples, and a clipboard score sheet. No multiple-choice test: the student shows mastery by running the floating-disk assay, separating pigments by chromatography, and tracing energy and carbon through the system aloud.
By the end of the Photosynthesis & Plant Energy unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Measure photosynthetic rate and separate leaf pigments.
The student traces energy and carbon through the system aloud (Page 4).
Disk-rise times, chromatograms, and conclusions kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Not yet, Approaching, or Mastered — the column language tells you which. A criterion counts as mastered only when the student can both run the lab and justify the plant biology behind it. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single bad afternoon never sinks the unit.
Accept any answer in the synonyms column — they are pre-approved as equivalent. The third column flags the confusions that look close but are not yet, so you can coach precisely.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Two stages | ||
| Light reactions | light-dependent stage | On the thylakoid membranes; make ATP and NADPH |
| Calvin cycle | light-independent stage; carbon fixation | In the stroma; fixes CO₂ into sugar — not “night-only” |
| ATP & NADPH | energy carriers | Made by the light reactions; spent in the Calvin cycle |
| Carbon fixation | CO₂ fixing | Building sugar from CO₂ — the source of plant mass |
| Chloroplast & pigments | ||
| Chloroplast | photosynthesis organelle | Where both stages happen; not in every cell |
| Thylakoid | membrane stack; grana | Site of the light reactions |
| Stroma | chloroplast fluid | Site of the Calvin cycle |
| Chlorophyll | green pigment | Absorbs red and blue, reflects green — why leaves look green |
| Pathways & mass | ||
| C3 / C4 / CAM | carbon-fixation pathways | Different strategies for the carbon-vs-water trade-off |
| Cellular respiration | sugar breakdown | Releases the energy stored in sugar; plants do it too |
| Dry mass | biomass | Comes mostly from atmospheric CO₂, not the soil |
| Stomata | leaf pores | Let CO₂ in for the Calvin cycle; also lose water |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Light reactions & the Calvin cycle | Treats photosynthesis as one vague step that “makes food.” | Names the two stages but cannot say what each produces or consumes. | Traces light energy to ATP and NADPH in the light reactions and their use to fix CO₂ into sugar in the Calvin cycle. |
| Chloroplast structure & pigments | Cannot locate where photosynthesis happens in the cell. | Names the chloroplast but not the thylakoids, stroma, or why leaves are green. | Maps the light reactions to the thylakoids and the Calvin cycle to the stroma, and explains how chlorophyll and accessory pigments absorb different wavelengths. |
| C3, C4 & CAM pathways | Assumes every plant fixes carbon the same way. | Names the pathways but cannot link them to climate or leaf structure. | Compares C3, C4, and CAM, and explains how each manages the trade-off between fixing carbon and losing water. |
| Respiration & the source of plant mass | Believes a plant's mass comes mainly from the soil. | Knows CO₂ is used but still credits the soil for most of the gain. | Explains that most dry mass comes from atmospheric CO₂, and traces sugar through cellular respiration to release its energy. |
| Lab technique (floating-disk assay & pigment chromatography) | Cannot get the disks to sink or run a readable chromatogram. | Runs the assay but mishandles the timing, light, or pigment separation. | Measures photosynthetic rate with the floating-disk assay and separates leaf pigments by chromatography, reading both results correctly. |
| Integration (cross-domain) | Treats the science as isolated facts. | Names a link to history, reading, or writing but cannot defend it. | Connects the unit across History · Reading · Writing and defends why it matters. |
The split between Approaching and Mastered is following the energy and carbon: not just naming a stage, but saying what it makes and where the plant's substance comes from. Ask “so where does the plant's mass actually come from?”
Read these before you grade. They show what Mastered and Not yet actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | Light reactions & the Calvin cycle | NY / Appr / Mast | |
| 2 | Chloroplast structure & pigments | NY / Appr / Mast | |
| 3 | C3, C4 & CAM pathways | NY / Appr / Mast | |
| 4 | Respiration & the source of plant mass | NY / Appr / Mast | |
| 5 | Lab technique (floating-disk & chromatography) | NY / Appr / Mast | |
| 6 | Integration (cross-domain) | NY / Appr / Mast |
☐ No ☐ Yes — for criterion: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
NY = Not yet · Appr = Approaching · Mast = Mastered · Unsure between two levels? Circle the lower one and note what a re-do would need.