Using PCR, a Student Wants to Amplify a Sequence of Known

question 158

Multiple Choice

Using PCR, a student wants to amplify a sequence of known DNA from a genomic DNA sample. The two primers are both designed to pair with sequences that have a 40% GC content. Using a particular set of denaturation temperatures, annealing temperatures, and extension temperatures, the experiment does not produce the expected single DNA fragment of a single known size, but instead a set of fragments of varied sizes. Which of the following could account for these results?

• A)The annealing temperature was too low so that the primers can bind with multiple genomic sequences that contain some mismatched bases.
• B)The denaturation temperature was too high so that the primers can bind with each other as well as with multiple genomic sites containing mismatches.
• C)The extension temperature was too low so that many fragments were terminated before the full fragment was replicated.

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Definitions:

Glutamate

An important neurotransmitter in the brain that plays a key role in learning and memory, also serving as a precursor for the synthesis of GABA in neurons.

Neurotransmitter

Chemical substances released by neurons to transmit signals across a synapse to another neuron, muscle, or gland.

Biological Processes

Any process that occurs within a living organism to maintain life, including growth, metabolism, reproduction, and response to stimuli.

Repolarization

The process of returning membrane potential to its resting level.