It is mainly about thermodynamics. The rate of reaction is proportional to the concentrations of the template and primer. The template is long so will tend to associate quickly with its other strand so we have to increase the concentration of primer so that the primers anneal and start to extend before the 2 strands of template dna re-anneal with each other

Here are a few reasons that explains the mechanism to some extent:

1. Efficiency: Using an excess of primers increases the chances of primer binding to the target DNA template. This enhances the efficiency of the PCR reaction by ensuring that a higher proportion of target DNA molecules are amplified.

2. Specificity: By using excess primers, it helps to compete against non-specific binding. Non-specific binding can occur when primers bind to unintended sequences in the DNA sample. The excess of specific primers increases the likelihood of specific binding to the target sequence, reducing the chances of non-specific amplification.

3. Yield: The use of excess primers increases the overall yield of the PCR product. Amplification efficiency is improved, resulting in a higher quantity of the desired PCR product being generated.

4. Error correction: Excess primers also help in error correction during PCR. DNA polymerases have an intrinsic proofreading activity that can correct errors that occur during DNA synthesis. By providing excess primers, it increases the chance for the DNA polymerase to proofread and correct any errors that may have occurred during amplification.

It's important to note that while using an excess of primers can be beneficial, there is a limit beyond which the excess can become detrimental. Too high a concentration of primers can lead to non-specific amplification, primer dimers, and other artifacts, so it is essential to optimize the primer concentration for each specific PCR reaction.

In PCR (polymerase chain reaction), excess primers are used to ensure that there are enough primers available to bind to the template DNA strands and initiate the amplification process.

During PCR, the DNA template is mixed with two short primers that are complementary to the DNA sequence flanking the region of interest. These primers serve as the starting point for DNA synthesis by the polymerase enzyme.

By using an excess of primers, the likelihood of at least one primer binding to the template DNA strand increases. This increases the efficiency of PCR, as more copies of the target DNA sequence can be amplified in a shorter period of time. Additionally, using an excess of primers can help to minimize the formation of primer dimers, which are non-specific products that can interfere with the amplification of the target DNA sequence.

However, it is important to note that using too much primer can lead to non-specific amplification, which can result in the amplification of unintended DNA sequences. Therefore, the optimal amount of primer to use depends on the specific PCR protocol and the nature of the DNA template being amplified.

Using extra primers guarantees that all of the template DNA strands are amplified and bound by primers, even if there are minute differences in the template sequence that may prevent primer binding. By reducing non-specific amplification of unwanted areas of the template DNA, the use of extra primers also contributes to improving the specificity of the reaction.

It's used so that after the denaturation step, the two separated strands of DNA do not hybridize with each other. it's based on the law of mass action. when the concentration of primers is high, it allows the DNA template strand to bind specifically with the primers instead of rehybridization with the other DNA strand.

Using excess primers in PCR can help prevent mispriming and unspecific amplification by ensuring that there are enough primers available to bind to the target DNA during the annealing step.

During PCR, the primers anneal to the template DNA strands and serve as a starting point for DNA synthesis. Excess primers are added to ensure that there are enough primers to bind to the template DNA strands, even if some primers bind to non-target sequences or if some primers are degraded over time.

If there are not enough primers available, non-specific amplification products can be formed, leading to false positive results. Additionally, excess primers can help reduce the effects of inhibitors that may be present in the reaction mix, which can interfere with the PCR reaction and lead to inaccurate results.

However, adding too much primer can also cause problems such as the formation of primer-dimers, which can compete with the target sequence for binding to the primers and result in lower amplification efficiency. Therefore, the optimal amount of primers to use may need to be determined experimentally for each PCR reaction.

These video playlists might be helpful to you:

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