The worksheet needs two counts at each stage: chromosomes per cell and chromatid copies per cell. Without that distinction, a correct-looking diagram can support an incorrect explanation.
An original simplified 2n = 4 model
Teaching model, not specimen data: the starting cell has completed DNA replication. It contains two homologous pairs, labeled A/a and B/b. Each chromosome has two sister chromatids. The model simplifies away crossing-over detail; this omission does not mean biological meiosis lacks variation.
| Stage shown | Cells | Chromosomes per cell | Chromatids per cell | What separates |
|---|---|---|---|---|
| Replicated start | 1 | 4 | 8 | Nothing separated yet |
| After division I | 2 | 2 | 4 | Homologous chromosomes |
| After division II | 4 | 2 | 2 | Sister chromatids |
Meiosis I separates homologs while sister chromatids remain together. Meiosis II separates those sister chromatids, with no intervening DNA replication. The cells already have one homologous set after division I; division II does not halve that set again. OpenStax's meiosis section explains those distinctions.
Follow the identities through both divisions
One original arrangement sends A and B into one division-I cell and a and b into the other. Label A's sisters A1/A2, B's B1/B2, a's a1/a2, and b's b1/b2. The division-II drawings then show A1/B1 in one cell, A2/B2 in another, a1/b1 in a third, and a2/b2 in a fourth.
This is one chosen schematic arrangement, not the only possible assortment or a complete model of gamete development. Sister labels here identify copies in the simplified no-crossing-over drawing; they are not a claim that all biological sister chromatids remain identical after recombination.
Ask “What remains joined after division I?” The key is the sister chromatids of each replicated chromosome. Ask “What separates in division II?” The key is those sister chromatids. Feedback should point to the labels involved, not merely display “two cells” or “four cells.”
Make the counting explanation inspectable
Keep the declared replicated start visible beside the selected stage. An answer of “two chromosomes after division I” needs per cell: there are two cells, each with two replicated chromosomes. Across both cells there are still four chromosomes at that shown stage.
For the final panel, show four cells with two single-chromatid chromosomes each. Avoid showing one chromosome per final cell; that would mistakenly halve this model's haploid set again.
A local exercise can select division I or II and ask which structures separate. Changing stage should update the diagrams, counts, and feedback together. Reset restores the original replicated start and clears answers. Keep drawings original and provide the full labeled cell contents in text.
Copy a model-specific worksheet brief
Create an original meiosis worksheet in US English.
Learner context: [enter or TO CONFIRM]
Source-supported stage facts: [paste with URLs]
Declared starting state and chromosome set: [enter]
Original homolog/sister labels: [paste]
Model simplifications: [enter]
Separate homolog separation in I from sister separation in II. Show cell
count, chromosomes per cell and chromatids per cell at each selected stage.
No second DNA replication occurs between divisions. Preserve identities
through original diagrams and complete text descriptions. State omitted
crossing-over detail without implying no biological variation. Do not claim
specimen, fertility, health interpretation, or actual learner results.
Return model contents, items, keys and reasoning feedback. If requested,
provide HTML local practice with stage choice, keyboard answers and reset.
Keep stage labels/counts consistent; reset returns the declared start and
clears feedback. No response collection or automatic proficiency diagnosis.
Check the per-cell counts and copy labels with a teacher before using the exercise. NOS can save and display an HTML chromosome-model copy for that comparison. Keep the simplified starting state beside the activity so learners can explain what separates without silently changing what is being counted.