Meselson and Stahlʹs experiments involved growing E. coli on a medium containing 15N (heavy nitrogen) which increased the density of the bacterial DNA. Cells were then grown on a medium containing only 14N. DNA samples were obtained for analysis after one, two and three rounds of replication (generations) and centrifuged on a density gradient. The double-helical DNA forms bands in the gradient depending on its density. How many bands did Meselson and Stahl see after two generation of cells were grown on the 14N medium?

TLS Online TPP Program

#Question id: 16487

#Unit 12. Applied Biology

Few limitations regarding organ culture 

It can be maintained only for a few months

Not suitable for biochemical and molecular analyses

For each study, fresh organ cultures have to be initiated

It denatures very easily

Which of the above statements are correct? 

TLS Online TPP Program

#Question id: 16488

#Unit 12. Applied Biology

Advantages of organ culture are

TLS Online TPP Program

#Question id: 16489

#Unit 12. Applied Biology

The beginning of animal tissue culture can be traced when Arnold showed that 

TLS Online TPP Program

#Question id: 16490

#Unit 12. Applied Biology

Significance of producing transgenic plants are aimed at producing 

TLS Online TPP Program

#Question id: 16491

#Unit 12. Applied Biology

Which was the first transgenic variety to reach market

TLS Online TPP Program

#Question id: 16492

#Unit 12. Applied Biology

Upstream elements on the other hand regulates the activity of gene action are

A. Enhancer sequences

B. Silencer sequences

C. Termination sequences

D. Signal sequences

Mark the option with correct combination