Question

Meselson and Stahl experiment proved

• A. DNA is a genetic material
• B. Central dogma of life
• C. Transformation process
• D. Semi-conservative DNA replication
• E. Transduction process

Answer 1

The correct option is D Semi-conservative DNA replication

Meselson and Stahl cultured bacteria in a N${}^{15}$ medium to get the DNA of heavy density. Then, bacteria were shifted to a N${}^{14}$ medium, DNA of replication cycles 0, 1, and 2 was isolated. The DNA was all of intermediate density after one replication cycle and ruled out the conservative replication model, which predicts that both heavy density DNA and light density DNA will be present. This result proved the semi-conservative replication model, according to which all DNA molecules will consist of one N${}^{15}$-labeled DNA strand and one N${}^{14}$-labeled DNA strand. The result of second replication cycle were also in consistent with semi-conservative replication model. Correct option is D.