THE MOLECULAR BASIS OF INHERITANCE
RECOMBINANT DNA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Primers are created.
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The primers attach to the target DNA region.
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Primers copy the new DNA strand.
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Primers sequence DNA
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Detailed explanation-1: -During this stage the reaction is cooled to 50-65⁰C. This enables the primers to attach to a specific location on the single-stranded template DNA by way of hydrogen bonding (the exact temperature depends on the melting temperature of the primers you are using).
Detailed explanation-2: -In PCR, a DNA sample is heated up to denature the two strands. These single strands are used as templates to replicate the DNA. Then the sample’s cooled slightly so small pieces of DNA, called primers, can bind or anneal to the template strands. These primers will set the borders for the DNA to be copied.
Detailed explanation-3: -Extension: after annealing, the temperature is increased to 72 degrees Celsius and the Taq DNA polymerase enzyme is used for replicating the DNA strands. During synthesis (or extension), two identical double stranded DNA molecules are synthesized.
Detailed explanation-4: -If the annealing temperature is too high, primers are unable to bind to the template.
Detailed explanation-5: -After the separation of DNA strands, 18 to 20 base pair long polynucleotide primers are added to the reaction mixture. These primers form H-bonds with the template DNA strand and provide the free 3’-OH group for DNA synthesis. This process is known as primer annealing.