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Multiple Choice
Why is DNA replication considered a semi-conservative process?
A
Each new DNA molecule is composed entirely of original strands.
B
Each new DNA molecule contains two new strands and two original strands.
C
Each new DNA molecule is composed entirely of new strands.
D
Each new DNA molecule consists of one original strand and one new strand.
Verified step by step guidance
1
Understand the concept of DNA replication: DNA replication is the process by which a DNA molecule makes a copy of itself. This is crucial for cell division, allowing each new cell to have a complete set of DNA.
Learn about the semi-conservative model: The semi-conservative model of DNA replication suggests that each of the two new DNA molecules will have one strand from the original DNA molecule and one newly synthesized strand.
Explore the experimental evidence: The semi-conservative model was confirmed by the Meselson-Stahl experiment, which used isotopic labeling to demonstrate that after replication, each DNA molecule consisted of one old and one new strand.
Compare with other models: Other models, such as the conservative and dispersive models, were proposed but did not match experimental evidence. The conservative model suggested that the original DNA molecule remained intact, and a completely new molecule was synthesized. The dispersive model suggested that each strand of both DNA molecules was a mix of old and new DNA.
Conclude why DNA replication is semi-conservative: Based on the evidence and the definition of the semi-conservative model, each new DNA molecule consists of one original strand and one new strand, making DNA replication a semi-conservative process.