Students who demonstrate understanding can: 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.
Official wording from the Next Generation Science Standards (NGSS Lead States, 2013). NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the NGSS were involved in the production of this page, and they do not endorse it. View on nextgenscience.org
Genes are sections of DNA on chromosomes, and each gene carries instructions for making a protein. Proteins do most of the work in an organism: they build structures such as hair and muscle, carry oxygen in the blood, and speed up reactions. Because traits depend on proteins, a change in a gene can change a trait.
A change in the structure of a gene is called a mutation. Students develop and use a model to explain why a mutation may lead to a different protein, or to no working protein at all, and why the effect on the organism can be harmful, beneficial or neutral. A harmful example is a mutation that stops the protein for blood clotting from working properly. A beneficial example is a mutation that lets a bacterium survive an antibiotic. Many mutations are neutral and cause no noticeable change.
The model stays conceptual: gene to protein to trait. Students do not need the molecular details of protein synthesis or names for specific mutation types.
Many mutations have no effect, and some are helpful, such as those that give resistance to a disease. Movies have made mutation sound like a dangerous word.
Mutations occur randomly. A bacterium does not mutate because an antibiotic is present; an existing mutation simply helps it survive when the antibiotic arrives.
A gene is an instruction; the trait is the result of the protein the instruction produces. The model chain is gene, then protein, then trait.
A mutation changes a gene for a pigment protein in a moth so that it makes more dark pigment. Use a model to explain the change and decide whether it is harmful, beneficial or neutral.
Answer: The mutation changed the gene, which changed the pigment protein and made the wings darker; whether that helps or harms depends on the color of the background the moth rests on.
A simple coded-message activity models the idea well: change one letter in a written instruction and see whether the result still makes sense, makes something different, or fails. Then map the activity onto gene, protein and trait.
Keep examples at the whole-organism level and avoid naming mutation types, which the assessment boundary excludes. Ask students to classify the effect of each example and justify their choice.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: D) A protein
Each gene codes for a protein, and proteins shape traits.
Answer: mutation (also accepted: a mutation, mutations)
A mutation is a change in the genetic material.
Answer: B) Mutations can be harmful, beneficial or neutral
Mutations vary in effect; many are neutral and some are helpful.
Answer: C) Gene, protein, trait
The gene's instructions produce a protein, and the protein affects the trait.
Answer: D) Beneficial to the bacteria
It helps the bacteria survive in that environment.
Answer: chromosomes (also accepted: chromosome)
Genes are sections of DNA found on chromosomes.
Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.
A full lesson with slides, activities and an exit ticket on mutations, proteins and traits, pitched to grades 6-8 and editable in PowerPoint or Google Slides.
Make a lesson βA printable, differentiated worksheet on MS-LS3-1 with an answer key, ready in about a minute.
Make a worksheet βTurn mutations, proteins and traits into a quiz students answer online that marks itself, with a class summary for you.
Build a test βNo. The assessment boundary excludes molecular-level changes, the mechanisms of protein synthesis and specific types of mutations.
Changes to genes can lead to different proteins, which can change an organism's traits in harmful, beneficial or neutral ways.