AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

STRUCTURE OF NUCLEIC ACIDS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
During DNA replication, what occurs?
A
The hydrogen bonds between pairs of nitrogenous bases are broken
B
The covalent bonds between pairs of nitrogenous bases are broken
C
The hydrogen bonds between sugar and phosphate molecules are broken
D
The covalent bonds between sugar and phosphate molecules are broken
Explanation: 

Detailed explanation-1: -During DNA replication breaking of H-bond is required to uncoil the DNA. When the DNA replication starts, the parent DNA double helix uncoils and splits into single DNA strands by breakdown of hydrogen bonds.

Detailed explanation-2: -Posted April 29, 2022. Hydrogen bonds in DNA replication are broken down by the helicase class of enzymes. This causes the double-stranded DNA molecule to unzip into two single strands, allowing each strand to be replicated.

Detailed explanation-3: -The initiation of DNA replication occurs in two steps. First, a so-called initiator protein unwinds a short stretch of the DNA double helix. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.

Detailed explanation-4: -In general, DNA is replicated by uncoiling of the helix, strand separation by breaking of the hydrogen bonds between the complementary strands, and synthesis of two new strands by complementary base pairing.

Detailed explanation-5: -The nitrogenous bases of each strand face each other and complementary bases hydrogen bond to each other, stabilizing the double helix. Heat or chemicals can break the hydrogen bonds between complementary bases, denaturing DNA.

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