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6.8 Biotechnology

Syllabus
2025
Topic
6.8
Level
—

Learning objectives

6.8A—Explain the use of genetic engineering techniques in analyzing or manipulating DNAExplain the use of genetic engineering techniques in analyzing or manipulating DNA.• Genetic engineering techniques can be used to analyze and manipulate DNA and RNA.- i. Gel electrophoresis is a process that separat es DNA fragments by size and charge.- ii. During polymerase chain reaction (PCR), DNA fragments ar e amplified by denaturing DNA, annealing primers to the original strand, and extending the new DNA molecule.- iii. Bacterial transformation introduces foreign DNA int o bacterial cells.- iv. DNA sequencing technology determines the order of nucleotides in a DNA molecule. T ypically, these techniques result in a DNA fingerprint that allows for the comparison of DNA sequences from various samples.- Exclusion: Knowledge of the details of each of these genetic engineering techniques is beyond the scope of the AP Exam.

Choosing a Technique to Analyze or Manipulate DNA

Genetic engineering techniques analyze or manipulate DNA and RNA in different ways. The correct technique is chosen by the required outcome: copy DNA, separate fragments, introduce DNA into cells, or determine nucleotide order.

Technique What it does Main use or output
Gel electrophoresis Separates DNA fragments by size and charge Produces a fragment pattern that can help compare samples
Polymerase chain reaction (PCR) Amplifies selected DNA through denaturation, primer annealing, and extension Produces many copies of a DNA fragment for analysis
Bacterial transformation Introduces foreign DNA into bacterial cells Manipulates bacterial genetic information
DNA sequencing Determines the nucleotide order in a DNA molecule Provides sequence information for comparison

A bounded analysis workflow can combine techniques: PCR increases the amount of target DNA; electrophoresis separates resulting fragments; the fragment pattern or nucleotide sequence can then be compared among samples. Such comparison patterns are often described as DNA fingerprints.

Each PCR cycle first separates the DNA strands, then allows primers to anneal to complementary target sequences, and finally extends new DNA. Repeating the cycle amplifies the target fragment rather than merely moving or separating it.

Gel electrophoresis separates fragments but does not amplify them; PCR amplifies DNA but does not reveal the full nucleotide order; transformation changes which DNA a bacterial cell contains. Detailed procedures for these techniques are outside the required AP scope.