Skip to content
Login Register

#melting temperature

6 public questions tagged with this topic.

PCR

For primer Tm = 4(G+C)+2(A+T), Tm of 3 GC and 4 AT is

The Wallace rule approximates melting temperature as Tm = 4(G+C) + 2(A+T), where GC contributes three hydrogen bonds and AT contributes two, providing higher thermal stability for GC pairs. For a primer composition containing three GC and four AT bases, energetic contribution from GC equals 4×3 =12°C and from AT equals 2×4=8°C. Summation yields 20°C, representing temperature at which half of duplex dissociates into single strands. Although modern nearest-neighbor thermodynamic algorithms provide greater accuracy for longer oligos, this formula remains fundamental for NEET-type quick calculatio

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
PCR

Tm of a primer is calculated by

Melting temperature of short oligonucleotides dictates annealing conditions and assay success. The Wallace rule provides rapid estimation for primer design: Tm = 4°C × (G+C) + 2°C × (A+T). Guanine-cytosine pairs form three hydrogen bonds contributing greater thermal stability than adenine-thymine pairs with two bonds, thus weighted higher in formula. This approximation applies to primers shorter than about 20 bases and guides optimization of annealing temperature in PCR and hybridization experiments. Accurate Tm prediction ensures specific primer binding, minimizing non-specific products while

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
Transcript analysis

The formula for calculating melting temperature (Tm) is:

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.

View Details
DNA

The Wallace rule for calculating melting temperature of DNA is:

Tm = 4(G+C) + 2(A+T) is obtained by applying the relevant formula or quantitative relationship to the given parameters. In DNA, numerical problem-solving requires understanding the mathematical relationships between biological variables. The calculation involves substituting the provided values into the appropriate equation and solving systematically. The other options (Tm = 2(A+T) + 4(G+C), Tm = 4(A+T) + 2(G+C), and Tm = 2(G+C) + 4(A+T)) result from common calculation errors such as using incorrect formulas, misidentifying variables, inverting ratios, or making arithmetic mistakes.

Ref: Molecular Biology of the Gene, Watson et al., 7th Ed.

View Details
DNA

Which of the following factors does NOT increase the melting temperature of DNA?

Increased AT content is the correct choice because it does not accurately describe or belong to the category addressed in this question. In the context of DNA, the other options (High GC content, High ionic strength, and Stacking interactions) are all valid and well-established concepts. Increased AT content is either unrelated to the topic, describes a different biological process, or represents a common misconception. Questions framed as 'which is NOT' require students to identify the exception among otherwise correct statements, demanding comprehensive knowledge of the topic rather than rec

Ref: Molecular Biology of the Gene, Watson et al., 7th Ed.

View Details
DNA

The melting temperature (Tm) of DNA depends on:

All of the above is the scientifically accurate answer to this question. Within the study of DNA, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of All of the above directly address what is being asked. Among the other options, GC content, Ionic strength, and pH do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.

Ref: Molecular Biology of the Gene, Watson et al., 7th Ed.

View Details