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Multiple Choice
What type of interaction keeps the two complementary strands of a piece of DNA together?
A
Covalent bonds
B
Ionic bonds
C
Hydrogen bonds
D
Van der Waals forces
Verified step by step guidance
1
Understand the structure of DNA: DNA is composed of two complementary strands that form a double helix. These strands are made up of nucleotides, which include a sugar, a phosphate group, 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 about the type of bond between the bases: The two complementary strands of DNA are held together by hydrogen bonds between the nitrogenous bases. Adenine and thymine form two hydrogen bonds, while cytosine and guanine form three hydrogen bonds.
Differentiate hydrogen bonds from other types of interactions: Hydrogen bonds are weak, non-covalent interactions that occur between a hydrogen atom and an electronegative atom (like oxygen or nitrogen). They are distinct from covalent bonds (strong bonds within molecules), ionic bonds (electrostatic attraction between charged particles), and Van der Waals forces (weak intermolecular forces).
Conclude why hydrogen bonds are ideal for DNA: Hydrogen bonds provide enough stability to hold the strands together while allowing them to separate during processes like replication and transcription, which is essential for the function of DNA.