Define recombinant DNA
Describe recombinant DNA as DNA joined from different sources.
A Level; Cambridge International Biology 9700, 2028–2030. This is curriculum teaching, not medical advice or a claim that a treatment is suitable for an individual. Written responses are self-checked
Before you begin
- DNA stores genetic information; genes can be expressed to produce RNA and protein.
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Quick readiness check
What makes DNA recombinant in genetic engineering?
What you will learn
- Define recombinant DNA
- Explain the role of a DNA insert and a vector
Build the explanation
Recombinant DNA contains DNA sequences joined from different sources. In genetic engineering, a desired gene may be inserted into a vector such as a plasmid so the combined DNA can be transferred into a host organism. The insert and vector become part of one engineered DNA molecule.
Use the evidence carefully
A plasmid is a vector, not the gene itself. Recombinant DNA describes the combined DNA molecule; it does not by itself guarantee that a transferred gene will be expressed or that the organism will show a desired characteristic.
Pause and explain
A recombinant plasmid enters a cell but the host makes no protein. Why is this possible?
Worked example
A donor gene is joined to plasmid DNA. What is the combined DNA called?
Show the worked solution
- The molecule contains DNA from two sources.
- It is recombinant DNA.
Answer Recombinant DNA, because the joined molecule contains DNA sequences from different sources.
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A vector contains a gene copied from another organism. Name the engineered DNA molecule.
Give me a hint
Identify the relevant material or technology and explain each step.
Compare my reasoning
- The insert and vector have different sources.
- The joined molecule is recombinant DNA.
Recombinant DNA, because the joined molecule contains DNA sequences from different sources.
Look for these in your work
- Method identified
- Steps linked to function
Why is the plasmid called a vector in a gene-transfer process?
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Use the stated example to justify a conclusion.
Compare my reasoning
- It carries the gene sequence.
- It can move the insert into a host.
The plasmid acts as a vector because it carries the inserted DNA into a host cell.
Look for these in your work
- Evidence interpreted
- Limits stated
A recombinant plasmid enters a cell but the host makes no protein. Why is this possible?
Give me a hint
Apply the idea to a new application or trade-off.
Compare my reasoning
- Transfer alone does not ensure expression.
- Promoter and host compatibility may matter.
The DNA may not be expressed. A suitable promoter and compatible host transcription and translation machinery may be needed.
Look for these in your work
- Application explained
- Claim appropriately bounded
Common mistakes
- Calling the plasmid the inserted gene
- Assuming recombination automatically produces expression
What can you explain now?
What makes DNA recombinant in genetic engineering?
Compare with the explanation
DNA sequences from different sources are joined
The combined molecule contains the inserted sequence and vector DNA.
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Make it stick
What are the two DNA components in a basic recombinant vector?
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