Life Sciences · Lesson 03

CRISPR & Synthetic Biology Lab

CRISPR-Cas9 lets scientists cut DNA at a precise location and rewrite the genetic code. Design a guide RNA, target a gene, and watch your virtual bacteria glow — or resist antibiotics — depending on your edit.

How It Works

  • Cas9 — molecular scissors guided to a specific DNA target
  • Guide RNA — a 20-base sequence that matches the target gene
  • PAM site — a short motif (NGG) that Cas9 requires to bind
  • Repair — cell fixes the cut, often disabling (knockout) or inserting new code

Bacterial Genome Viewer

Design Your Guide RNA

Your guide RNA must match a sequence adjacent to a PAM site (NGG) to cut successfully.

Hint: Target sequence is GCACTGTTGGAAACGTCGAT. Type its complement (A↔T, C↔G).

1. Select Target Gene

Choose which gene to edit: luxA (bioluminescence) or ampR (antibiotic resistance). Each has different PAM sites and outcomes.

2. Design Guide RNA

Type a 20-nucleotide sequence that complements the target. The simulator highlights matches and warns of off-target sites.

3. Cas9 Cuts

If your guide matches a valid PAM-adjacent target, Cas9 creates a double-strand break. Watch the animation of the molecular scissors.

4. Observe the Result

The cell repairs the cut. A knockout disables the gene; an insertion adds new function. Check the petri dish to see if your bacteria glow.

Petri Dish — Result