Common Core LiteracyGrades 11–12Science & Technical

RST.11-12.3: Following a Procedure, Explaining the Results

Also written as CCSS.ELA-LITERACY.RST.11-12.3 · Cluster: Key Ideas and Details.

The Official Wording

Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.

Common Core State Standards, Grades 11-12, Reading: Science & Technical Subjects · Read it at the source · Checked October 14, 2026

What RST.11-12.3 Means in Plain English

Juniors and seniors carry out a long lab or technical procedure exactly as written, then explain their results with the text’s own explanations. A biology lab manual for cutting a plasmid and running it on a gel explains why uncut DNA runs ahead of its size.

Ninth and tenth grade (RST.9-10.3) followed procedures precisely, watching for the special cases and exceptions the text defined. Grades 11-12 add analysis: why the results came out as they did. This is the last band of the line, the lab reading college and career readiness asks for.

RST.11-12.3 I Can Statements

I can follow a multistep lab procedure exactly as written.
I can use the text’s explanations to account for each result.
I can connect an unexpected result to a step that changed.

RST.11-12.3 Worked Example

The lab manual and group 4’s results are invented for this page. Every band has an explanation in the notes, and only the strong answer uses them.

Read the Story

Procedure. Mix the plasmid with the restriction enzyme and incubate at 37 °C for 60 minutes; a shorter digestion can leave some plasmid uncut. Load the DNA ladder in lane 1, uncut plasmid in lane 2 and the digested plasmid in lane 3 of a 1 percent agarose gel, with the wells at the negative electrode, and run at 100 volts for 40 minutes.Notes. DNA carries a negative charge, so it moves toward the positive electrode, and shorter pieces travel farther. The plasmid is a circle 5,000 base pairs long. Uncut, it is supercoiled, twisted tightly on itself, and runs ahead of a straight piece of the same length. One cut opens the circle into a single straight piece; two cuts make two pieces whose lengths add up to 5,000.Results, group 4 (digested for 35 minutes because of a fire drill). Lane 2: one band level with the ladder’s 3,000 base-pair band. Lane 3: a strong band level with the 5,000 base-pair band, and a faint band level with the band in lane 2.

A short passage written for this page.

Question: What do the bands in lanes 2 and 3 show about the plasmid and the enzyme? Use the manual’s explanations to account for each band.

Not Yet“Lane 2 shows the plasmid is 3,000 base pairs long. Lane 3 has two bands, so the enzyme cut the plasmid twice, into a 5,000 piece and a 3,000 piece.”It reads each band straight off the ladder and ignores the manual’s notes. Supercoiled DNA runs ahead of its true length, and two pieces cut from one 5,000 base-pair circle could never add up to 8,000.

Meets the Standard“Lane 2 is the uncut plasmid. It lines up with 3,000 only because it is supercoiled and ‘runs ahead of a straight piece of the same length,’ not because it is 3,000 base pairs long. In lane 3, the strong band at 5,000 is the circle opened into one straight piece, so the enzyme cut once: two cuts would make two pieces adding up to 5,000, and nothing in the lane is smaller. The faint band matches lane 2, so it is plasmid the enzyme never reached. That fits the procedure’s warning, since group 4 digested for 35 minutes instead of 60. Repeating the digestion for the full 60 minutes should make the faint band disappear.”It explains every band with a specific note from the manual, rules out the two-cut reading with arithmetic, and ties the faint band to the one step the group did not follow.

Question Stems to Use

Which step of the procedure did the group change, and what does the text say that change can do?Which note in the manual explains this band?What would the gel look like if the enzyme had cut twice?Does this band’s position on the ladder tell you its true length? Why or why not?What would you repeat to confirm your explanation?

Common Mistakes with RST.11-12.3

Reading every band straight off the ladder

“The uncut plasmid is 3,000 base pairs.”

Try this: Have students find the manual’s note on each kind of DNA before sizing any band, and annotate which note applies to it.

Treating a changed step as bad luck

“Our gel had an extra band, so something went wrong.”

Try this: Ask students to compare their log with the procedure step by step and link each unexpected result to a specific change they made.

Following the steps without reading the notes

A group that loads every lane perfectly and then cannot explain a single band

Try this: Assign the notes section as reading before lab day, with one question per note about what it predicts the gel will show.

Where RST.11-12.3 Fits

Comes BeforeRST.9-10.3Follow a complex procedure precisely, attending to special cases or exceptions the text defines.

AlongsideRST.11-12.4Work out what terms like supercoiled and base pair mean in this specific lab context.WHST.11-12.2Write up a procedure and its results so each step and explanation builds on the last.

Comes NextRST.11-12.8Judge a study’s data, analysis and conclusions, verifying the data when possible.

Practice RST.11-12.3

Quick Check

Why does the uncut plasmid line up with the 3,000 base-pair band when it is 5,000 base pairs long?
Uncut, it is supercoiled, and the notes say supercoiled DNA runs ahead of a straight piece of the same length.
How many times did the enzyme cut the plasmid, and how do you know?
Once. The strong band at 5,000 is a single straight piece; two cuts would give two smaller pieces adding up to 5,000.
What explains the faint band in lane 3?
Some plasmid stayed uncut because group 4 digested for 35 minutes instead of 60, which the procedure warns can leave plasmid uncut.

RST.11-12.3: Other Names

RST.11-12.3CCSS.ELA-LITERACY.RST.11-12.3