MS-LS3-1: How Mutations Can Change Proteins and Traits
Also called NGSS MS-LS3-1 · Topic: Growth, Development, and Reproduction of Organisms · Life Science
The Official Wording
Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.
Clarification statement: Emphasis is on conceptual understanding that changes in genetic material may result in making different proteins.
Assessment boundary: Assessment does not include specific changes at the molecular level, mechanisms for protein synthesis, or specific types of mutations.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-LS3-1 Means in Plain English
Middle schoolers use a model to explain that genes on chromosomes carry instructions for making proteins, and proteins shape an organism's traits. When a gene changes, the protein may change too, and the result can hurt the organism, help it, or make no real difference.
Students explain the idea, not the chemistry: they do not study how proteins are built step by step or name types of mutations. This follows how genes are inherited (MS-LS3-2) and leads to how DNA codes for proteins (HS-LS1-1).
MS-LS3-1 I Can Statements
- I can explain that genes carry instructions for making proteins.
- I can model how a change in a gene can change a protein.
- I can sort mutation effects into harmful, helpful and neutral.
MS-LS3-1 Worked Example
A paper airplane model where the folding card plays the gene and the plane plays the protein.
Can a change in one instruction change how well the finished product works?
Set It Up: A card of eight folding steps for a paper airplane, copy paper, a die, a stack of change cards and a tape measure in the hallway.
- Fold a plane exactly from the card and fly it three times.Original: mean 5.2 m
- Roll the die to pick a step, then draw a change card for that step.Step 3: fold 1 cm deeper
- Copy the card with the change, fold a new plane and fly it three times.Changed plane: mean 2.1 m
- Repeat with new rolls and pool results across the class.Most planes worse, some same, a few better
- Sort every change as harmful, neutral or helpful for distance.Harmful 14, neutral 9, helpful 3
Most changes made the plane fly worse or no differently, and only a few made it fly farther.
Why it works: A gene is a set of instructions, so changing one instruction can change the shape of the protein it builds and how well that protein works.
Common Mistakes with MS-LS3-1
Thinking every mutation is harmful
“Mutations always cause disease.”
Try this: Many mutations change nothing that matters, and a few help, such as one that lets some adults digest milk sugar.
Skipping the protein step
“The gene changed, so the eye color changed.”
Try this: Put the protein in the middle: the gene changes, the protein it makes changes, and that changes the trait.
Thinking organisms mutate on purpose
“The bacteria mutated so they could survive.”
Try this: Mutations happen by chance, without a goal. Whether one helps depends on the organism's surroundings, not on what it needs.
Where MS-LS3-1 Fits
Practice MS-LS3-1
Quick Check
- What do genes give instructions for?
- A mutation changes a gene but the protein works the same. What kind of effect is that?
- How could one mutation be harmful in one place and helpful in another?