DNA replication results in two DNA molecules that:

• A. are both composed entirely of newly synthesized strands
• B. contain only RNA nucleotides
• C. are both identical to the original DNA molecule except for random mutations
• D. each contain one original strand and one newly synthesized strand

Answer: (D)

Verified step by step guidance

1. Understand the concept of DNA replication: DNA replication is a semi-conservative process, meaning that each new DNA molecule consists of one original (parental) strand and one newly synthesized (daughter) strand.
2. Recall the role of complementary base pairing: During replication, the enzyme DNA polymerase adds nucleotides to the growing daughter strand by matching them with their complementary bases on the parental strand (A pairs with T, and G pairs with C).
3. Visualize the process: The double-stranded DNA unwinds with the help of helicase, creating a replication fork. Each parental strand serves as a template for the synthesis of a new complementary strand.
4. Recognize the outcome: After replication, two identical DNA molecules are formed. Each molecule contains one strand from the original DNA (the parental strand) and one newly synthesized strand, ensuring genetic consistency.
5. Connect to the question: The correct answer is that each new DNA molecule contains one original strand and one newly synthesized strand, which aligns with the semi-conservative nature of DNA replication.