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AP Biology · Unit 6: Gene Expression & Regulation

6.8 Biotechnology

Tools for working with DNA

Biotechnology uses lab tools to study and manipulate genes. PCR (polymerase chain reaction) makes millions of copies of a DNA segment. Gel electrophoresis separates DNA fragments by size using an electric field (smaller pieces travel farther).

Editing and combining DNA

Restriction enzymes cut DNA at specific sequences. Cutting DNA from two sources and joining them makes recombinant DNA (often carried in plasmids). CRISPR is a precise gene-editing tool. These techniques create transgenic organisms (GMOs), medicines, and more.

Key terms

PCR
Polymerase chain reaction — amplifies a DNA segment into millions of copies.
Gel electrophoresis
Separates DNA fragments by size using an electric field.
CRISPR
A precise gene-editing tool that targets specific DNA sequences.
Restriction enzyme
An enzyme that cuts DNA at specific recognition sequences.
Recombinant DNA
DNA combined from two different sources, often carried in a plasmid.

Try an AP-style question

Data

Gel electrophoresis: Suspect 1 has bands at 500 and 1,200 bp; Suspect 2 at 300 and 900 bp; crime-scene DNA at 300 and 900 bp.

Which conclusion is best supported?

  1. The crime-scene DNA matches neither suspect
  2. The crime-scene DNA matches Suspect 2
  3. The crime-scene DNA matches both suspects
  4. The crime-scene DNA matches Suspect 1
Show the answer

B. Identical banding patterns indicate a DNA match.

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