Question

In reference to the rough and smooth bacteria cells that were modified and then injected into mice: What combination of bacteria would not kill a mouse?

a) Live S cells mixed with dead S cells
b) Dead R cells mixed with dead S cells
c) Live S cells mixed with dead R cells
d) Live R cells mixed with dead S cells

Answer 1

The combination of bacteria that would not kill a mouse is live R cells mixed with dead S cells, as both cell types are dead and incapable of causing infection or undergoing transformation.

Step-by-step explanation:

The combination of bacteria that would not kill a mouse is live R cells mixed with dead S cells.

1. When live S cells are mixed with dead S cells (option a), the live S cells are able to transform the dead S cells and become pathogenic, causing the mouse to die.
2. Dead R cells mixed with dead S cells (option b) will not harm the mouse since both strains are non-pathogenic.
3. When live S cells are mixed with dead R cells (option c), the live S cells can transform the dead R cells and become pathogenic, causing the mouse to die.
4. The correct combination is live R cells mixed with dead S cells (option d) because the live R cells are non-pathogenic and the dead S cells cannot be transformed into the pathogenic form.