In DNA replication, what is the direct substrate used by DNA polymerase to synthesize a new DNA strand?

• A. Ribonucleoside triphosphates (NTPs)
• B. Deoxyribonucleoside triphosphates (dNTPs)
• C. Amino acids
• D. Okazaki fragments

Answer: (B)

Verified step by step guidance

1. Understand the role of DNA polymerase in DNA replication: DNA polymerase is the enzyme responsible for synthesizing a new DNA strand complementary to the template strand.
2. Recall that DNA polymerase adds nucleotides to the growing DNA strand by forming phosphodiester bonds between nucleotides.
3. Identify the chemical form of the nucleotides that DNA polymerase uses as substrates: these are nucleotides with three phosphate groups attached, providing the energy for bond formation.
4. Distinguish between ribonucleotides (used in RNA synthesis) and deoxyribonucleotides (used in DNA synthesis). DNA polymerase specifically uses deoxyribonucleoside triphosphates (dNTPs) as substrates.
5. Conclude that the direct substrates for DNA polymerase during DNA replication are deoxyribonucleoside triphosphates (dNTPs), not ribonucleoside triphosphates (NTPs), amino acids, or Okazaki fragments.