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#lab technique

2 public questions tagged with this topic.

DNA & RNA isolation

Which is *not* used in RNA isolation?

RNA isolation requires potent RNase inhibitors and denaturants such as GITC which chaotropically inactivates RNases, and phenol-chloroform which partitions RNA into aqueous phase while denaturing proteins. Chloroform aids phase separation and removes lipids. SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, is an analytical method for separating proteins by size based on SDS-denatured migration, not an extraction method for RNA. It is used post-extraction for protein analysis and would degrade RNA preparations. Thus SDS-PAGE has no role in RNA isolation workflow and is unrel

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 homogenization tool forces cells through a narrow space?

Dounce homogenizer is a manual tissue grinder consisting of a glass tube and tightly fitting pestle with narrow clearance. Cells suspended in buffer are forced through this narrow annular space, generating mechanical shear and pressure differentials that rupture plasma membranes while preserving organelles if clearance is controlled. This contrasts with bead beater which uses bead collision, sonicator which uses acoustic cavitation, and freeze-thaw which uses ice crystal damage. Dounce is gentle, ideal for preparing nuclei and subcellular fractions without vigorous denaturation of sensitive co

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