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Multiple Choice
In the structure of DNA, what role do hydrogen bonds play between the nitrogenous bases?
A
They form the backbone of the DNA molecule by linking deoxyribose sugars and phosphate groups.
B
They hold the two complementary strands of DNA together by connecting specific pairs of nitrogenous bases.
C
They catalyze the replication of DNA by breaking and reforming covalent bonds.
D
They attach the DNA molecule to histone proteins in the nucleus.
Verified step by step guidance
1
Understand the structure of DNA: DNA is a double helix composed of two strands of nucleotides. Each nucleotide consists of a phosphate group, a deoxyribose sugar, and a nitrogenous base.
Identify the nitrogenous bases: The nitrogenous bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair specifically: adenine pairs with thymine, and cytosine pairs with guanine.
Learn the role of hydrogen bonds: Hydrogen bonds are weak interactions that occur between the nitrogenous bases of the two strands. These bonds are responsible for holding the two strands of DNA together.
Understand base pairing specificity: Hydrogen bonds form between specific pairs of nitrogenous bases. Adenine and thymine are connected by two hydrogen bonds, while cytosine and guanine are connected by three hydrogen bonds. This ensures the complementary nature of the DNA strands.
Clarify the function of hydrogen bonds: Hydrogen bonds do not form the backbone of DNA (which is made of covalent bonds between deoxyribose sugars and phosphate groups), nor do they catalyze replication or attach DNA to histone proteins. Their primary role is to stabilize the double helix by connecting complementary bases.