Liposome-mediated delivery — stability and protection of nucleic acids In plant liposome-mediated gene transfer, how do liposomes affect the nucleic acid cargo?
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AThey protect nucleic acids from nuclease digestion
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BThey provide a relatively stable environment for the nucleic acid payload
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CBoth (a) and (b)
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DThey render nucleic acids unstable inside the vesicles
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EThey enzymatically replicate the DNA payload
Answer
Correct Answer: Both (a) and (b)
Explanation
Introduction / Context:Liposomes are lipid bilayer vesicles that encapsulate biomolecules, including nucleic acids, shielding them from extracellular degradation and facilitating delivery into cells. In plant systems, this is most effective with protoplasts.
Given Data / Assumptions:
- Nucleases in extracellular milieu can degrade naked DNA/RNA.
- Encapsulation within liposomes limits nuclease access.
- Bilayer vesicles provide a stabilizing microenvironment during delivery.
Concept / Approach:
The protective and stabilizing roles of liposomes are central to their utility. They do not inherently replicate DNA; instead, they carry and release it after fusion or endocytosis. Thus, both protection from nucleases and improved stability are correct statements.
Step-by-Step Solution:
Identify risks to naked nucleic acids (nuclease degradation).Note how lipid encapsulation reduces exposure.Recognize that vesicles maintain cargo integrity during handling and fusion.Select ‘‘Both (a) and (b).’’Verification / Alternative check:
In vitro digestion assays show reduced nuclease access to encapsulated nucleic acids, confirming protection and improved stability.
Why Other Options Are Wrong:
Liposomes do not make nucleic acids unstable nor do they replicate DNA; replication requires polymerases, not lipid vesicles.
Common Pitfalls:
Assuming delivery vehicles alter the genetic material enzymatically; liposomes are carriers, not catalysts.
Final Answer:
Both (a) and (b)