Mississippi Science GEN.1B.2

ScienceGrades 9–12Genetics

The Standard

GEN.1B: Students will analyze how the DNA sequence is copied and transmitted to new cells.

Develop and use models to illustrate the mechanics of DNA replication.

2026 Mississippi College- and Career-Readiness Standards for Science · Structure and Function of DNA

Teacher's field guide

What Students Need to Do: Students model the two DNA strands separating. They add complementary bases to each original strand. They show that each finished molecule has one original strand and one new strand.
What Mastery Looks Like: Given a short DNA sequence, a student pairs A with T and C with G on both new strands. Their model shows the original strands in separate finished molecules.
Common Misconceptions: Students may copy the same letters onto a new strand instead of using complementary bases. Some show the original molecule staying together while an entirely new molecule forms.
How to Assess It: Give students a six-base-pair DNA diagram. Ask them to draw the two finished molecules and mark each strand as original or new.

Lesson moves

Have students separate two paired paper DNA strands, then tape different-colored base pieces to each strand to build two molecules.
Show a finished DNA model and ask, 'Why does each molecule contain one original strand?' Have students write a two-sentence answer.
Play Replication Repair: show three diagrams with wrong base pairs or misplaced original strands, and have teams fix them.
Give students a drawing of a healing cut and ask them to mark when skin cells copy DNA before dividing.

Free download

A ready-to-print activity worksheet aligned to GEN.1B.2, with an answer key for the teacher on its own page. No account needed.

PDF, US Letter, prints cleanly in black and white.

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