Multiple Choice
Which two scientists are most widely credited with establishing the double-helix structure of DNA in 1953?
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7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
In the DNA double helix, what molecules form the sugar-phosphate backbone of each strand?
A
Alternating deoxyribose sugars and phosphate groups linked by phosphodiester bonds
B
Alternating ribose sugars and phosphate groups linked by peptide bonds
C
A polypeptide chain of amino acids linked by glycosidic bonds
D
A chain of nitrogenous bases (A, T, G, C) linked by hydrogen bonds
Verified step by step guidance1
Recall the structure of the DNA double helix, which consists of two strands running in opposite directions.
Identify that each strand is made up of repeating units called nucleotides, and each nucleotide contains a sugar, a phosphate group, and a nitrogenous base.
Understand that the sugar in DNA is deoxyribose, not ribose (which is found in RNA).
Recognize that the sugar and phosphate groups alternate along the backbone of each strand, connected by strong covalent bonds called phosphodiester bonds.
Note that the nitrogenous bases (A, T, G, C) extend from the sugar-phosphate backbone and pair with bases on the opposite strand via hydrogen bonds, but they do not form the backbone themselves.
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