Question

what would happen if the protein coat of a virus that infects a bacterium is labeled with radioactive sulfur and DNA of the virus is labeled with radioactive phosphorus?

Answer 1

normally, you inject the virsses into a bacteria culture. after a certain cultivation time, you centrifugate your culture and will only find the radioactive phosphorous.

this happens because only the viral DNA will actually invade the bacterium. the protein coat stays outside since it is no longer needed and would draw too much attention to the infected cell (that is even more important for organisms with an immune system).

Answer 2

so what you are saying is that only the phsophorus will be found inside the bacterium?

Answer 3

yes. and since you centrifugated the bacteria from the supernatant (which contains the viral protein coat), you won't find sulfur.

Answer 4

okay thank you so much i was very confused

Answer 5

Plus, this is the condition for " phages", because as a phage infecting a bacteria, its "coat" stays outside the bacteria and injects DNA into the bacteria.

Answer 6

since phages are, in fact, viruses, your answer is valid. :)