Gene Delivery and Transformation Methods
Getting DNA into Cells
Delivery challenges
A construct is only useful if it reaches the right cell type and remains functional. Delivery strategy depends on the organism, tissue, payload size, and whether transient or stable expression is desired.
Common delivery methods
Heat shock or chemical transformation
- Common in bacteria
- Simple and inexpensive
Electroporation
- Uses electric pulses to open membranes
- Works across many cell types
Which method uses an electric pulse to help DNA enter cells?
Electroporation transiently permeabilizes membranes with an electric field.
Correct answer: Electroporation
Which delivery method is especially associated with plant cells?
Particle bombardment can force DNA-coated particles through tough plant cell walls.
Correct answer: Particle bombardment
What is one advantage of viral vectors in animal cells?
Viruses naturally evolved to enter cells, so modified viral vectors can be highly efficient.
Correct answer: They can deliver genetic material efficiently
Transient vs stable
Transient delivery produces temporary expression, while stable integration or maintenance can persist through cell division.
How delivery choice is made
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Step 1: Identify the target organism or cell type.
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Step 2: Estimate the size and complexity of the DNA payload.
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Step 3: Decide whether expression should be temporary or permanent.
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Step 4: Balance efficiency, cost, and safety.
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Step 5: Select the delivery platform and optimize conditions.
Why is delivery often harder in plants than in bacteria?
The physical structure of plant cells makes DNA uptake more challenging.
Correct answer: Plant cells have rigid cell walls and additional barriers to DNA entry