Question

Who performed experiments on Vicia faba to prove that the DNA replicates semi-conservatively?

• A. Taylor and colleagues
• B. Matthew Meselson
• C. Stahl
• D. Hershey and Chase

Answer 1

The Correct Option is A

In the study of DNA replication, the semi-conservative model suggests that each strand of the original DNA molecule serves as a template for the formation of a new complementary strand. To understand who confirmed this model, one must look back at historical experiments. 

One pivotal experiment that contributed to the semi-conservative model of DNA replication was conducted by Taylor and colleagues in 1958. They used the plant Vicia faba, commonly known as the broad bean, as a model organism. Their study involved autoradiography techniques combined with radioactive labeling using tritium-labeled thymidine. By observing chromosome behavior during the replication process, they provided supporting evidence for the semi-conservative nature of DNA replication.

In contrast, Meselson and Stahl are more famously known for their experiments with E. coli that further confirmed the semi-conservative mechanism through nitrogen isotope labeling. Hershey and Chase, meanwhile, are renowned for their work on bacteriophages that helped establish DNA as the genetic material, rather than proteins.

Therefore, the correct answer to the question regarding experiments on Vicia faba proving DNA replication is semi-conservative is "Taylor and colleagues".

Answer 2

The experiment conducted by Taylor and his colleagues in 1958 on Vicia faba (broad bean) demonstrated that DNA replicates semi-conservatively. This experiment showed that during DNA replication, each strand of the original DNA molecule serves as a template for a new strand. As a result, the two daughter DNA molecules each contain one original strand and one newly synthesized strand.

This semi-conservative model was proven through labeling DNA strands with radioactive isotopes, and following their distribution during cell division. Taylor and colleagues' work was fundamental in confirming that DNA replication is semi-conservative, as opposed to the conservative or dispersive models.