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#nucleic acid extraction

3 public questions tagged with this topic.

DNA & RNA isolation

The silica column binds nucleic acids at:

Silica column technology for nucleic acid purification depends on chaotropic salts like guanidinium hydrochloride. At high salt concentration, water molecules are stripped from silica and DNA phosphate backbone, and chaotropic agents disrupt hydrogen bonding networks. This dehydrates silica surface and DNA, allowing formation of cation bridges and hydrogen bonds between negatively charged DNA and silica. At low salt or water, hydration restores and DNA elutes. Binding fails at low salt, high pH alone does not drive adsorption, thus high salt is essential for efficient nucleic acid capture and

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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DNA & RNA isolation

GITC is primarily used in RNA isolation for:

GITC (guanidinium isothiocyanate) is a powerful chaotropic agent used in RNA isolation methods like TRIzol. It simultaneously lyses cells, denatures proteins, and inactivates RNases instantly by disrupting hydrogen bonding and hydrophobic interactions, unfolding secondary structures. RNases are extremely resilient and require strong denaturants; GITC at 4 M denatures them irreversibly, protecting RNA from degradation. It does not primarily digest proteins enzymatically, inhibit DNases selectively, or solubilize lipids only. Combined with phenol, it allows partitioning of intact RNA into aqueou

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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DNA & RNA isolation

Which method purifies DNA using magnetic particles?

Magnetic bead purification uses paramagnetic particles coated with silica or carboxyl groups that reversibly bind nucleic acids. Under high salt and chaotropic conditions, DNA adsorbs to bead surface via electrostatic and hydrophobic interactions. An external magnetic field immobilizes beads, allowing washing to remove proteins, salts, and contaminants. Elution in low salt buffer releases pure DNA. This method avoids centrifugation and toxic organics, is automatable, and yields high purity. It differs from column chromatography, CTAB extraction, and isopropanol precipitation which do not use m

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

View Details