DNA strands can be pulled apart by adding heat and "melting" the double-stranded DNA. The temperature required to melt a region of DNA changes based on the base-pair composition
Based on the structure of the A-T and C-G bonds in the accompanying figure, which bonds would require more energy (heat) to break them? How might this help you predict which regions of the DNA helix may be the most stable and harder to break apart?
C-G bonds contain three hydrogen bonds, whereas A-T bonds have only two hydrogen bonds. The more hydrogen bonds in a particular region of DNA, the more energy required to break those bonds apart. Thus, regions of DNA with large numbers of C and G residues will be more heat resistant (and probably transcribed less often) than A-T rich regions.
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If your mother is heterozygous for Huntington disease, which is caused by a dominant allele, the odds
of your inheriting the disorder from her are
a. 1/4. b. 1/2. c. 3/4. d. 1. e. 0.
Who developed the science of taxonomy?
a. Charles Darwin b. Aristotle c. Alfred Russel Wallace d. Sir Isaac Newton e. Carolus Linnaeus
Which of the following is not true of coliforms?
A. Coliform counts are not specific for a particular species of bacteria. B. They include E. coli, Enterobacter, and Giardia. C. They are gram-negative, lactose-fermenting, and gas-producing. D. Finding coliforms in water indicates fecal contamination.