Eukaryotic Gene Expression Problem Set

Tutorial to help answer the question


Problem 5: DNA-DNA renaturation and DNA-RNA hybridization

Which statement is NOT true about nucleic acid hybridization?
A. it depends on complementary base pairing
B. a polysaccharide can hybridize with a DNA strand
C. a DNA strand can hybridize with another DNA strand
D. an RNA strand can hybridize with a DNA strand
E. double strand DNA denatures at high temperature


Denaturation of DNA
Both DNA and RNA are able to form hybrids in solution with other DNA or RNA molecules that have complementary base pairing. Double-stranded DNA can be "denatured" by heating to high temperature. If the resulting single-stranded DNAs are slowly cooled, the separated DNA strands can reanneal to reform the DNA duplex as suggested by the following illustration:

DNA and RNA pairing
Notice that A pairs with T and G pairs with C when a DNA strand hybridizes with another DNA strand.

An RNA molecule can also form a base-paired DNA-RNA duplex molecule with a DNA that has complementary base pairing. The most common source of DNA complementary to an mRNA is the DNA coding strand that was the template for synthesis of the RNA. In DNA-RNA hybrid formation, G base pairs with C, A of the RNA pairs with T of the DNA, and U or the RNA pairs with A of the DNA. The DNA-RNA hybridization reaction is illustrated below:

The Biology Project
University of Arizona
Monday, October 27, 1997
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