MS-LS1-2: How Cell Parts Work Together
Also called NGSS MS-LS1-2 · Topic: Structure, Function, and Information Processing · Life Science
The Official Wording
Develop and use a model to describe the function of a cell as a whole and ways the parts of cells contribute to the function.
Clarification statement: Emphasis is on the cell functioning as a whole system and the primary role of identified parts of the cell, specifically the nucleus, chloroplasts, mitochondria, cell membrane, and cell wall.
Assessment boundary: Assessment of organelle structure/function relationships is limited to the cell wall and cell membrane. Assessment of the function of the other organelles is limited to their relationship to the whole cell. Assessment does not include the biochemical function of cells or cell parts.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-LS1-2 Means in Plain English
Students build and use a model of a cell as a working system. They explain the main job of the cell membrane, cell wall, nucleus, mitochondria and chloroplasts, and how each part helps the whole cell stay alive and do its work.
Students look closely at how the membrane and the wall fit their jobs, and treat other parts only by their role in the whole cell, with no chemistry. This builds on MS-LS1-1 and leads to body systems in MS-LS1-3.
MS-LS1-2 I Can Statements
- I can explain what the cell membrane and cell wall do.
- I can describe how the nucleus and mitochondria help the cell.
- I can use a model to show a cell working as a system.
MS-LS1-2 Worked Example
A model-cell test a class can run with raw eggs, vinegar, corn syrup and a kitchen scale.
How does a membrane control what moves into and out of a cell?
Set It Up: Raw eggs soaked in vinegar for two days to dissolve the shells, cups of water and corn syrup, and a kitchen scale.
- Rinse a shell-less egg, our model cell, pat it dry and weigh it.Starting mass 80 g
- Soak it in water overnight, then dry and weigh it again.88 g, firm and swollen
- Move it into corn syrup overnight, then rinse, dry and weigh it.61 g, soft and wrinkled
- Model a plant cell by filling a water balloon inside a small cardboard box.The box holds the balloon's shape
The egg gained mass in water and lost mass in corn syrup, so water crossed its membrane in both directions.
Why it works: A membrane lets water and some small particles pass while holding others back, and in plants a stiff cell wall outside the membrane keeps the cell from bursting.
Common Mistakes with MS-LS1-2
Giving animal cells a wall
“Animal cells have a cell wall too.”
Try this: Every cell has a membrane, but only plant, fungus and many bacterial cells add a stiff wall outside it. Animal cells have no wall.
Thinking the membrane is a solid barrier
“Nothing can get through the membrane.”
Try this: The membrane is selective. It lets water, oxygen and some food molecules through while keeping many other substances out.
Listing parts without the whole cell
A labeled diagram with no link between the parts
Try this: Explain how parts work together: the nucleus directs the cell, mitochondria release energy from food, and the membrane controls supplies.
Where MS-LS1-2 Fits
Practice MS-LS1-2
Quick Check
- Why don't plant cells burst when they take in lots of water?
- Which cell part releases energy from food for the cell to use?
- Why do root cells have no chloroplasts?