Which of these events happens after the translation of mrna begins at the start codon?

a.) termination mediated by termination factors

b.) initiation mediated by initiation factors

c.) regulation mediated by regulatory factors

d.) elongation mediated by elongation factors

c) labeled DNA ... DNA

Explanation:

Hersey and Chase prepared two separate virus samples and infected the host cell, E. coli, that was present into different culture media. One of them contained a radioactive isotope of phosphorus (³²P) and the other contained a radioactive isotope of sulfur (³⁵S). After a division cycle in bacteria, all the viruses recently formed had one of the two isotopes depending on the culture media in which infected bacteria had grown. Viruses coming from bacteria incubated with ³²P had radioactive DNA whereas viruses coming from bacteria incubated with ³⁵S had radioactive proteins. This was due to the differences between the structures of the DNA and proteins: DNA contains phosphorus, but not sulfur and the proteins contain sulfur in cysteine and methionine, but not phosphorus.

After incubation, the cells were centrifugated to separate any extracellular viral material. Hersey and Chase found out that ³⁵S remained outside of the bacterial cells, in the empty capsids, and that ³²P had entered the cells and was present in the new viruses formed. They concluded that the genetic material was DNA and not the proteins.