A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion?
1. the presence of the same photosynthetic pigments found in cyanobacteria
2. cell walls that lack peptidoglycan
3. cells that are isotonic to conditions on the surface of the fish
4. cells containing bacteriorhodopsin
5. the presence of very large numbers of ion pumps in its plasma membrane
A) 2 and 5
B) 3 and 4
C) 1, 4, and 5
D) 3, 4, and 5
E) 2, 3, 4, and 5

Halobacterium infection after salt curing of fish.

Explanation:

The correct choice is : E) 2, 3, 4, and 5

The features of cells removed from the surface of the fish that will confirm the infection is caused by Halobacterium are:

2. cell walls that lack peptidoglycan.

Because halobacterium are srchaebacteria and their cell walls are not made up of peptidoglycan.

3. cells that are isotonic to conditions on the surface of the fish .

If it was not isotonic to the surface condition then it would not have survived on the surface for longer.

4. cells containing bacteriorhodopsin

The red color  is due to presence of bacteriorhodopsin.

5. the presence of very large numbers of ion pumps in its plasma membrane.

Halobacterium is an aerobe it needs lots of energy and carries out respiration. A large number of proton pumps will regulate the proton gradient.