Principles of genetic engineering
Cambridge A-Level Biology (9700) · Unit 19: Genetic technology · 10 flashcards
Principles of genetic engineering is topic 19.1 in the Cambridge A-Level Biology (9700) syllabus , positioned in Unit 19 — Genetic technology , alongside Genetic technology applied to medicine and Genetically modified organisms. In one line: Recombinant DNA is a DNA molecule that has been created by joining together DNA fragments from different sources, often different organisms. This manipulation is a key component of genetic engineering.
Marked as A2 Level: examined at A Level in Paper 4 (A Level Structured Questions) and Paper 5 (Planning, Analysis and Evaluation). It is not tested on the AS-only papers (Papers 1, 2 and 3).
The deck below contains 10 flashcards — 2 definitions and 8 key concepts — covering the precise wording mark schemes reward. Use the 2 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
Recombinant DNA
Recombinant DNA is a DNA molecule that has been created by joining together DNA fragments from different sources, often different organisms. This manipulation is a key component of genetic engineering.
What the Cambridge 9700 syllabus says
2025-2027 syllabus, in our words · A2 LevelWhat the syllabus expects you to be able to do in this topic, in plain English. For the exact wording, see the official syllabus (PDF).
- Define recombinant DNA.
- Explain that genetic engineering means deliberately changing an organism's genetic material to alter particular characteristics, and that this can involve inserting a gene into the organism so that it is expressed.
- Explain that a gene for transfer into an organism may be obtained by: extracting it from a donor organism's DNA; making it from a donor organism's mRNA; or synthesising it chemically from nucleotides.
- Explain what plasmids, restriction endonucleases, DNA ligase, reverse transcriptase and DNA polymerase each do when a gene is transferred into an organism.
- Explain why the desired gene may need to be accompanied by a promoter when it is transferred into an organism.
- Explain how marker genes that code for fluorescent products can be used to confirm that a gene is being expressed.
- Explain that gene editing is a type of genetic engineering in which DNA is inserted, deleted or replaced at particular sites in the genome.
- Describe and explain the stages of the polymerase chain reaction (PCR) used to amplify and clone DNA, including what Taq polymerase does.
- Describe and explain the use of gel electrophoresis to separate DNA fragments that differ in length.
- Outline the use of microarrays to analyse genomes and to detect mRNA in gene expression studies.
- Outline the benefits of databases holding information on genome and gene nucleotide sequences, and on the amino acid sequences and structures of proteins.
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9700 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Define recombinant DNA.
Recombinant DNA is a DNA molecule that has been created by joining together DNA fragments from different sources, often different organisms. This manipulation is a key component of genetic engineering.
Explain how genetic engineering modifies an organism's characteristics.
Genetic engineering deliberately manipulates genetic material, often by transferring a gene into an organism. This transfer results in the expression of the new gene, leading to altered or novel characteristics in the modified organism, e.g. using bacteria to produce human insulin.
List three methods of obtaining genes for transfer into an organism.
Genes can be obtained by: 1. Extracting DNA directly from a donor organism. 2. Synthesising DNA from the mRNA of a donor organism using reverse transcriptase. 3. Synthesising DNA chemically from individual nucleotides.
Describe the role of restriction endonucleases in gene transfer.
Restriction endonucleases cut DNA at specific recognition sequences, creating defined fragments. These enzymes are crucial for isolating the desired gene from a donor organism and for opening up a plasmid vector to receive the gene.
What is the function of DNA ligase in creating recombinant DNA?
DNA ligase seals the phosphodiester bonds between DNA fragments, specifically joining the gene of interest and the vector DNA (
Why is a promoter sometimes transferred along with the desired gene?
A promoter region is essential for initiating transcription of the gene. If the host organism's cellular machinery does not recognize the gene's native promoter, the gene will not be expressed without the addition of a compatible promoter.
Explain how marker genes confirm gene expression.
Marker genes, such as those coding for fluorescent proteins (
Describe the polymerase chain reaction (PCR) and the role of Taq polymerase.
PCR is a technique used to amplify a specific DNA sequence. Taq polymerase is a heat-stable DNA polymerase that extends DNA from primers, creating multiple copies of the target sequence through repeated cycles of heating and cooling.
Explain how gel electrophoresis separates DNA fragments.
Gel electrophoresis separates DNA fragments based on size. Smaller fragments migrate through the gel matrix faster than larger fragments. This allows for visualization and analysis of DNA fragment sizes after staining.
Outline how microarrays are used to analyse gene expression.
Microarrays contain thousands of DNA probes corresponding to different genes. mRNA is extracted from a cell, converted to cDNA, labeled, and hybridized to the microarray. The amount of cDNA bound to each spot reveals the expression level of the corresponding gene.
Review the material
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Read NotesMore topics in Unit 19 — Genetic technology
Principles of genetic engineering sits alongside these A-Level Biology decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Principles of genetic engineering deck
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