5 public questions tagged with this topic.
Autoradiography uses radioactive probes to detect specific DNA sequences by hybridization.
Ref: NCERT Class 12 Biology Chapter 10: Biotechnology and its Applications Medical Applications - Molecular Diagnosis - PCR ELISA
DNA sequence similarity reflects key principle in quiz on molecular evolution, where evolutionary mechanisms shape genetic variation and adaptation. In this context, DNA sequence similarity aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why DNA sequence similarity fits helps integrate natural selection, environment.
Ref: Li, Molecular Evolution, Neutral Theory and Molecular Clocks.
Melting temperature represents the temperature at which fifty percent of an oligonucleotide duplex dissociates. For short oligonucleotides, typically less than 14 nucleotides, Wallace rule provides a rapid empirical estimate. Guanine-cytosine pairs form three hydrogen bonds and exhibit stronger stacking, contributing roughly 4 degrees Celsius per pair, while adenine-thymine pairs form two hydrogen bonds, contributing about 2 degrees per pair. Summation yields Tm = 4(G+C) + 2(A+T). This approximation guides primer design for PCR and probe hybridization, though more accurate nearest-neighbor the
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.
Nucleic acid hybridization is stabilized by specific non-covalent interactions. Hydrogen bonding between complementary bases confers specificity and contributes enthalpy. Base stacking interactions arising from hydrophobic effects and pi-pi overlap of aromatic rings greatly stabilize the double helix. Ionic interactions mediated by monovalent cations like Na+ shield negative charges of phosphate backbones, reducing electrostatic repulsion and increasing duplex stability. Van der Waals forces, while present in any molecular association, are not considered a major distinct stabilizing force for
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.
Ribosomal DNA is organized as tandem repeats containing 18S, 5.8S, and 28S coding regions separated by internal transcribed spacers and external spacers. A probe specific to 18S sequence, under stringent hybridization conditions, anneals by complementary base pairing only to regions containing 18S coding DNA or its mature RNA transcript, not to 28S or intronic regions. This specificity allows detection of small subunit rRNA on northern blots, assessment of RNA integrity, quantification of expression, or localization of rDNA loci on Southern blots, supporting studies of phylogeny and ribosome b
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.
