Question

When DNA replication starts

• A. the leading strand produces Okazaki fragments
• B. the hydrogen bonds between the nucleotides of two strands break
• C. the phosphodiester bonds between the adjacent nucleotides break
• D. the bonds between the nitrogen base and deoxyribose sugar break

Answer 1

Answer: (B)

On starting of DNA replication, the two strands of DNA double helix unwind with the help of DNA unwinding protein (also called DNA helicase). The unwinding occurs as this protein begins its binding DNA strands, thus, breaking the hydrogen bonds between complementary nitrogenous bases.