Here's an example of what's due today

PCR and primers

Wed, Oct 28, 2026 · Week 10 · Genetics of Disease (Medical Interventions)

Today's goal: Diagram the steps of PCR and explain how primers and restriction enzymes target specific DNA.

Learn first

What a finished product looks like

This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.

Labeled PCR diagram

Completes: Completes the PCR notebook page: a labeled three-step PCR diagram with temperatures, primer binding sites, a restriction-enzyme note, and a bridging sentence to gel electrophoresis.

Three PCR steps, with temperatures:

1. Denaturation (about 95 C): heat separates the double-stranded DNA into two single strands.

2. Annealing (about 55 to 65 C): the temperature drops so the two primers can bind to their matching flanking sequences.

3. Extension (about 72 C): Taq polymerase adds nucleotides, building a new strand from each primer.

Why primers control what is copied: Each primer is a short single-stranded sequence complementary to one end of the target. Only the region between the two primers gets copied, so the primer sequences decide exactly which stretch of DNA is amplified.

Restriction enzyme note: A restriction enzyme cuts double-stranded DNA at a specific palindromic recognition site, producing fragments of defined, predictable sizes.

Bridge to gel: PCR is needed first because it makes millions of copies of the target; without that amplification there would be far too little DNA to see as a band on a gel.

Bar chart of PCR step temperatures: denaturation at 95 C, annealing at 55 to 65 C, extension at 72 C.

Also due today: Submit your labeled PCR diagram to the course shell.

Check yourself

WebXam problem for today's skill

One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.

WebXam-style domain: Bio-Molecular TechnologySelf-check skill: Matching each PCR step to its purpose and temperature

During PCR, the reaction is cooled to about 55 to 65 C. What happens at this annealing temperature?

Tap an answer to see the full explanation. Nothing is recorded or graded.

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