HS-LS1-1: How DNA Builds Proteins
Also called NGSS HS-LS1-1 · Topic: Structure and Function · Life Science
The Official Wording
Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells.
Assessment boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-LS1-1 Means in Plain English
High school students explain, using evidence, how the order of bases in a gene sets the order of amino acids in a protein, and how a protein's shape lets it do a job. Cells that specialize make different proteins and form systems that keep an organism alive.
The goal is the big chain from gene to protein to cell to body, not memorizing named cell types, organ systems or particular proteins, and not the chemistry of how ribosomes work. It builds on MS-LS3-1 and leads to inheritance and mutation in HS-LS3-1 and HS-LS3-2.
HS-LS1-1 I Can Statements
- I can explain how a gene's base order sets a protein's amino acids.
- I can use a codon chart to translate a short DNA sequence.
- I can connect proteins to the jobs specialized cells do in a body.
HS-LS1-1 Worked Example
A paper model that lets students follow one short gene all the way to a chain of amino acids, then change a single base.
What happens to an amino acid chain when one DNA base changes?
Set It Up: Paper strips printed with a 12-base DNA sequence, a codon chart or codon wheel, and colored pencils.
- Copy the DNA strip TAC AAA CTT GGG into messenger RNA, pairing A with U, T with A, C with G and G with C.AUG UUU GAA CCC
- Read the RNA three bases at a time with the codon chart.Met, Phe, Glu, Pro
- Change the middle T of the third DNA triplet to A and translate again.GAA becomes GUA: Glu becomes Val
- Start over and change only the last base of the fourth triplet, G to A.CCC becomes CCU: still Pro
- Compare the three chains and mark which change would alter the protein's shape.One swap changes the chain, one does not
One base change swapped glutamic acid for valine, while a different single change left the chain exactly the same.
Why it works: Each three-base codon names one amino acid, and because several codons name the same one, some base changes alter the protein and some do not.
Common Mistakes with HS-LS1-1
Mixing up genes and proteins
“DNA is a protein that does the work in cells”
Try this: DNA stores the instructions. Proteins are the molecules built from those instructions, and they carry out most of the cell's jobs.
Thinking different cells have different DNA
“Muscle cells have muscle DNA and skin cells have skin DNA”
Try this: Nearly every body cell carries the same DNA. Cells specialize because each one switches on a different set of genes.
Reading the codon chart with DNA letters
Looking up TAC on the chart and finding nothing
Try this: Codon charts list RNA codons. First pair each DNA base to write the RNA, using U in place of T, then look it up.
Where HS-LS1-1 Fits
Practice HS-LS1-1
Quick Check
- A DNA triplet reads TAC. What RNA codon and amino acid does it give?
- Why can two cells with the same DNA do different jobs?
- Can a single base change leave a protein unchanged?