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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plasmids
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single-stranded DNA
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mRNA
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double-stranded DNA
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Detailed explanation-1: -cDNA is a more convenient way to work with the coding sequence than mRNA because RNA is very easily degraded by omnipresent RNases. This the main reason cDNA is sequenced rather than mRNA. Likewise, investigators conducting DNA microarrays often convert the mRNA into cDNA in order to produce their probes.
Detailed explanation-2: -The differentiating factor between DNA and cDNA is that the DNA comprises both introns and exons, whereas cDNA contains only exons – the coding regions.
Detailed explanation-3: -A cDNA probe can be generated from a specific mRNA. The mRNA, encoding a specific protein, is a template. By the action of reverse transcriptase and DNA polymerase, a cDNA is formed that can be used as a probe to hybridize with a specific gene sequence (Fig. 10.45).
Detailed explanation-4: -cDNA is produced in two basic steps: (a) first, mRNA is isolated from other cellular RNA using an elution column. (b) Second, the enzyme reverse transcriptase synthesizes strands of DNA using the mRNA molecules as templates.