GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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consists of sugars, phosphate groups, and bases
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has two strands held together with hydrogen bonds
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was the substance that transformed the bacteria in Griffith’s experiment
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contains adenine, guanine, thymine, and cytosine
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Detailed explanation-1: -Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA (not proteins) can transform the properties of cells, clarifying the chemical nature of genes.
Detailed explanation-2: -In a very simple experiment, Oswald Avery’s group showed that DNA was the “transforming principle.” When isolated from one strain of bacteria, DNA was able to transform another strain and confer characteristics onto that second strain. DNA was carrying hereditary information.
Detailed explanation-3: -However, the most definitive proof that the transforming principle was DNA was its sensitivity to specific enzymes, called DNAses, that specifically degrade different kinds of DNA. Avery and his colleagues were able to show that transforming activity was not destroyed by enzymes that degrade proteins or RNA.
Detailed explanation-4: -The idea of a nonheritable exchange of genetic information was first documented in 1928 with work on the pathogen Streptococcus pneumoniae (Griffith, 1928). Griffith showed that virulence factors from a killed pathogenic strain could “transform” a nonvirulent strain to become virulent as well.