Unit 02 · Cell Structure & Function
The big ideas here are the cell as the unit of life: the divide between prokaryotes and eukaryotes, the organelles that carry out a cell's work, how the membrane controls what enters and leaves, and why surface-area-to-volume ratio limits cell size. Mastery means reading a cell — under the scope or on paper — and explaining how its parts work together.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Organelle identification & function | Names few organelles; unsure of roles. | Identifies organelles; functions are partial. | Names organelles and states each one's job in the cell. |
| Membrane transport reasoning | Confuses diffusion, osmosis, and active transport. | Defines transport types but predicts direction unevenly. | Predicts solute movement and energy cost from a gradient. |
| Prokaryote / eukaryote distinction | Cannot reliably tell the two apart. | Lists one or two differences. | Contrasts the cell types by nucleus, organelles, and size. |
| Microscopy of cells | Cannot locate or focus a specimen. | Finds cells but struggles with magnification or focus. | Locates, focuses, and identifies cells across magnifications. |
| Structure–function connection | Treats parts as a list of names. | Connects one structure to its function with help. | Explains how a structure's shape enables its function. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“This cell is packed with rough ER and Golgi, so it’s making and shipping a lot of protein, and all the mitochondria tell me it burns a lot of energy — probably a secretory or muscle cell. Form follows function.”
“That’s the powerhouse one. The membrane keeps things inside. I can name the parts but not what the cell actually does.”
This unit is assessed at the microscope and in osmosis labs, with oral checks where you explain transport and structure–function in your own words. A criterion is mastered only when you can do the task and reason about it on a live specimen.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.