Multiple Choice
Which component is found in DNA but not RNA?
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7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
In nucleic acids, the backbone of DNA and RNA is primarily composed of which repeating structural components?
A
Alternating sugars linked directly to each other by glycosidic bonds, with phosphates as side groups
B
Alternating sugar and phosphate groups linked by phosphodiester bonds
C
Alternating nitrogenous bases and phosphate groups linked by hydrogen bonds
D
A repeating chain of amino acids linked by peptide bonds
Verified step by step guidance1
Recall the basic structure of nucleic acids (DNA and RNA), which consist of a sugar-phosphate backbone with nitrogenous bases attached.
Identify the repeating units in the backbone: the sugar (deoxyribose in DNA, ribose in RNA) and the phosphate group.
Understand the type of bond that connects these repeating units: the sugar and phosphate groups are linked by phosphodiester bonds, which form the backbone of the nucleic acid strand.
Recognize that glycosidic bonds connect the sugar to the nitrogenous base, not sugar to sugar, and that hydrogen bonds occur between complementary bases, not in the backbone.
Conclude that the backbone is made of alternating sugar and phosphate groups linked by phosphodiester bonds, which provides structural stability to the nucleic acid.
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